EPS Power steering column, what ACTUALLY goes wrong?

what ACTUALLY goes wrong on K12 columns? Very common fault it seems that these just pack in, even at low mileage, YOu can't fit a used one apparently even if you could find a working one, There are a couple of places who repair them, but at £250-£350. I'm fairly good at fixing things, tempted to strip it down, anyone done this? What actually causes these things to throw up codes etc, is it the torque sensors, assuming it is basically always the same fault with them, what to they actually 'fix' when you send them away does anyone know? Bought the car cheap today but I can see why they are cheap when they have broken EPS. These cars aren't worth much money these days especially early ones, so throwing £400 at one when it probably only worth £600 does not seem economical.

Can a 2nd hand column be fitted if you swap the control box from your old one onto it? Is it or is it likely the fault is actually within the control box rather than the electromechanical innards of the column. Is it ever something as simple as motor brushes?
 
Block diagram indicates a maintenance free microprocessor controlled power electronics invertor drive brush-less motor.

Local area network (LAN) data i/o portals indicate interface (digital two way handshake) with vehicle on-board can bus data coms;~ therefore second-hand swapped modules unlikely to be recognised without reprogramming.
Reference; http://manuals.co/workshop/nissan/micra/nissan-micra-workshop-manual-2005-(41)/1070/8 Pages; STC 8 thru STC 33.

Some useful threads on here if you search electric power steering & or EPS in the various forums you may benefit from other"s experience with this most difficult problem.
References; https://www.micra.org.uk/threads/electric-power-steering-failed.66017/#post-737637

http://www.honestjohn.co.uk/forum/post/?t=59770
 
Last edited:
Hi Datman, Hi Plmval,

I have just been asking myself the same question. The PS light came on yesterday on my 2004 K12 for the first time. I drove it to work with no PS, but restarted it when I got there and the fault cleared itself and has been OK today, but I fear it will be back eventually. My Wife and I have owned it from new and its done 55K.
There is much written on the web about this subject, but I haven't found anything yet to say EXACTLY what goes wrong. If I knew this I recon I could repair these all day long :)
I'm an electronic engineer with some experience with designing switches and electronics for cars (Lotus, Morgan, Elemental) and some CAN bus controls for Plant machinery (Niftylift).
From what I can tell, a brand new column from Nissan will fit straight on any car. Once it has been fitted it becomes coded to that car so you cannot just buy one from a scrap yard and swap it. It is possible to reprogram the EEPROM in a secondhand unit to make it 'virgin' again, provided you can find and download the program from somewhere.
But what actually goes wrong with the unit? If its a problem with the electronics I would suspect it is a problem with a failed solder joint somewhere, possibly on the MOSFET transistors that drive the motor. Otherwise I would suspect it is a problem with the actual motor.
I'm hoping it would be a case of re-soldering some components in the electronics then resetting the fault code(s).
I'm not going to take my unit apart yet as it has not failed permanently. If it starts to fail more frequently I will take a look.

If anyone has any new information on this subject it would be much appreciated. Obviously is IS possible to repair this common fault as there are a couple of companies out there doing it already (for a price).


Update 03/11/16 - just bought an N607 fault code reader as recommended be member 'superben' https://www.micra.org.uk/threads/nissan-micra-eps-issue.66286/

Been driving around for a few month now with no pas - pumped biceps but MOT is looming so need to fix it now :)
 
Last edited:
Hi Datman, Hi Plmval,

I have just been asking myself the same question. The PS light came on yesterday on my 2004 K12 for the first time. I drove it to work with no PS, but restarted it when I got there and the fault cleared itself and has been OK today, but I fear it will be back eventually. My Wife and I have owned it from new and its done 55K.
There is much written on the web about this subject, but I haven't found anything yet to say EXACTLY what goes wrong. If I knew this I recon I could repair these all day long :)
I'm an electronic engineer with some experience with designing switches and electronics for cars (Lotus, Morgan, Elemental) and some CAN bus controls for Plant machinery (Niftylift).
From what I can tell, a brand new column from Nissan will fit straight on any car. Once it has been fitted it becomes coded to that car so you cannot just buy one from a scrap yard and swap it. It is possible to reprogram the EEPROM in a secondhand unit to make it 'virgin' again, provided you can find and download the program from somewhere.
But what actually goes wrong with the unit? If its a problem with the electronics I would suspect it is a problem with a failed solder joint somewhere, possibly on the MOSFET transistors that drive the motor. Otherwise I would suspect it is a problem with the actual motor.
I'm hoping it would be a case of re-soldering some components in the electronics then resetting the fault code(s).
I'm not going to take my unit apart yet as it has not failed permanently. If it starts to fail more frequently I will take a look.

If anyone has any new information on this subject it would be much appreciated. Obviously is IS possible to repair this common fault as there are a couple of companies out there doing it already (for a price).


Update 03/11/16 - just bought an N607 fault code reader as recommended be member 'superben' https://www.micra.org.uk/threads/nissan-micra-eps-issue.66286/

Been driving around for a few month now with no pas - pumped biceps but MOT is looming so need to fix it now :)

Your concept mobile gym keep fit Micra with US EPS and “biceps” like Popeye could catch on and as a last resort you could try convincing the MOT tester of its merits?

Some K-12 owners on here have or have had EPS fault codes reset several times and extended its useful life. May be worthwhile verifying terminal PSU and earth potentials under full lock? Your EPS motor power circuits’ hypothesis may well have substance and is worth investigation following total failure.

Keep us posted how you get on with resets via N607, looming MOT and any eventual EPS power circuits inspection, test and work around repair that you may come up with?

Good luck ;)
 
Your concept mobile gym keep fit Micra with US EPS and “biceps” like Popeye could catch on and as a last resort you could try convincing the MOT tester of its merits?

Some K-12 owners on here have or have had EPS fault codes reset several times and extended its useful life. May be worthwhile verifying terminal PSU and earth potentials under full lock? Your EPS motor power circuits’ hypothesis may well have substance and is worth investigation following total failure.

Keep us posted how you get on with resets via N607, looming MOT and any eventual EPS power circuits inspection, test and work around repair that you may come up with?

Good luck ;)
LOL i could start a new tend.
I will keep you posted how I get on. I will try by just resetting the fault code for now.
I read somewhere there are 2 relays in the unit that can fail intermittently, so might take a look at how easy it is to replace them.
I wonder if it is possible to just 'drop' the steering column from the dash with the linkage and wheel still attached to get access to the control unit?
That way I could maybe check the voltages at the connector too. Might be possible to 'operate' on the control unit without removing it from the car, which would be rather handy. I guess as long as I disconnect the battery and keep the wheel dead ahead it should be fine.
More later....
 
Hey all,

Now I am on my laptop I can reply properly.

I used to work at the manufactures of ther EPS System (TRW Automotive), where I worked in the Warranty Department analysising all UK and a percentage of international Warranty Returns to improve Manufacturing of the product. I also did some dealer visits and vehicle investigations in my time aswell.

So basically, I know everything there needs to know about the Nissan K12 EPS System.

You are correct, you cannot fit a second hand unit to a vehicle because the system handshakes with a dongle to the BCM and restricts ignition on if the dongle does not match. I know people who have fitted second hand units to their vehicle and it's worked, but not sure how they did this (I do have my opionions how you could possible do this but wouldn't want to broadcast on an open forum - becuase I am not total convinced and never tried it). I don't think TRW ever released the knowhow on clearing the dongle, when I visited Nissan Technical Centre to do some testing on a vehicle - not even Nissan had the ability to clear the dongle on the EPS System.

Next Subject, Fault Codes. The System has many internal fault codes which only display to a handful of DTC on the vehical. If the system identfies a failure it will generate a internal fault code and reduce the asssistance to 0% by disengaging the moter relay for safey. On ignition cycle the fault will be cleared unless it's a hard failure and the fault code will regenerate. If the fault code is generated 3 times in a row then the system latches and generates a System latch and can only be cleared by a diagnostics machine over CAN. These fault codes are Level A, Level B and Level C failures within the system. Level A Failures are normally CAN Issus (Communication Protacol), Level B are hardware failures and Level C are Latch Faults.

During the production there were known hardware and software issues within the system which was resolved during manufacturing. Earlier Systems are more common to fail then later systems. Software failure are normally intermittent and fails but when cleared would normally not fail again.

The system is designed in 3 blocks, ECU, Motor and Torque Sensor. The Motor was manufactured by Globe Motors and are very reliable apart from the Relay that is fitted. The Torque Sensor is an optical system produced in a clean room environment and the ECU was manufactured internally by a sister plant. I wouldn't recommend anyone trying to repair or opening the system without knowning what they are doing. I have questions a few of the re-manufacturing companies that state they repair the systems asking what exactly do they repair (just out of interest) but never got a reply. I would really question their intentions because I know TRW would never release the source Code or Database Files for any external site to repair the EPS. I was working in Prague for 1 year to estblish a Re-Manufacturing process for the EPS Systems and to be honest, it never hit off due to safety and the manufacturing plant didn't want to release the source code - it's agood job I had all what I needed! TRW always said that no system would ever be released if a Failure ever occured regardless of cause; I remember we had a production failure where the test machine was created internal fault codes into the system and all the systems were scrapped (over 200).

The system works on the CAN System of the vehicle and transmit and receives data to and from the ECM, BCM etc.. The system can be interigated with TRW mapped databases and internal parameters can be monitored and configurated over the CANbus. This was never released (as I'm aware) to the general public or Nissan.

Unforntunatly TRW lost the contract for the K12 system in 2009 (I think - if I remember correctly) which was unforntunaity becuase by 2006+ the system was really good and I would recommend the system to anyone. I beleive Delphi now produce the system for the K13 and also a retro fit for the K12 for the TRW replacement. I left TRW in 2010 and went on to bigger and better things.. but I do still know alot about the system and could really help someone if needed with reading the internal fault codes and resetting the dongle if required.

Another thing that I didn't talk about - The system has diffenrent Tune data for different Car configurations, without reading my old notes this was, Perol, Diesal, Sport and C+C Model Range. The system has boost curves, self steering centring and all the good stuff which can be configured with the right tools.

As someone said above, the system does have 2 relays, These are actually called a Link relay and Motor Relay. The Motor Relay is to activate the motor, and to disable the 3-phase motor on failure if required. The Link relay is on the ECU.

I'm trying to answer all the questions above with alittle of information, faults can be caued due to the relays but it's just as likely to be an internal hardware failure. a spec of dust in the torque sensor or a software issue. As I said previously, the system has many faults ( i think around 130ish) and these are assigned to about 5 DTCs so therefore the below DTC might have 100's of root causes. i.e DTC 5606 might be due to the Motor Relay, or the FET Drive for the Mototr the hall sensor which monitor the Motor or the motor feedback circuit. So basically could be either Motor or ECU Fault - in Warranty we barely looked at the DTC unless the system had no internal fault codes because it never helped!

DTC Number Description
5601 Battery Voltage Fault
D000 CAN Bus Fault
5609 CAN Vehicle Speed Fault
5611 CAN RearGearEngaged Invalid
5603 EPS Transient Fault
5604 EPS Operation Fault – Torque Sensor
5606 EPS Operation Fault – Motor
5607 EPS Operation Fault – NVM
5608 EPS Operation Fault – ECU
5604 EPS Internal Fault – Torque Sensor
5606 EPS Internal Fault – Motor
5607 EPS Internal Fault – NVM
5608 EPS Internal Fault – ECU

If someone needs specific details then private message me and I'll try and help.

The TRW System does get some negative feedback - but to be honest I like it. I like it that much I have fitted it to my kit car, this maybe because I can get it working and do some fancy stuff with it - but it's worked really well..

I think I have answered as much as I can - my wife is giving me that look to get off my laptop.

If I can post other helpful stuff I will.

P.S I live in Birmingham - UK so if anyone is around I'm sure I can help. I actually went to a scrap yard yesterday and got 2 EPS off a Micra for spares for my kit Car, knowing if it fails it easier to chnage it. Only takes 10 minutes to remove the EPS (from a scrap car) the bottom of the dash does get in the way and I break it on the scrap car!!!

Hope it made sense and everyone gets alittle information.

Jason
 
what ACTUALLY goes wrong on K12 columns? Very common fault it seems that these just pack in, even at low mileage, YOu can't fit a used one apparently even if you could find a working one, There are a couple of places who repair them, but at £250-£350. I'm fairly good at fixing things, tempted to strip it down, anyone done this? What actually causes these things to throw up codes etc, is it the torque sensors, assuming it is basically always the same fault with them, what to they actually 'fix' when you send them away does anyone know? Bought the car cheap today but I can see why they are cheap when they have broken EPS. These cars aren't worth much money these days especially early ones, so throwing £400 at one when it probably only worth £600 does not seem economical.

Can a 2nd hand column be fitted if you swap the control box from your old one onto it? Is it or is it likely the fault is actually within the control box rather than the electromechanical innards of the column. Is it ever something as simple as motor brushes?
Hello! If the warning light EPS stay on. Need the obd to detect the the fault. When the diagnostic tool can't connect to the EPS system that mean the eps modul is damage. In my country we just buy a second hand eps it cost around £156 - £294.
 
OP
OP
D
From huttojb: Hey all,

I used to work at the manufactures of ther EPS System (TRW Automotive), where I worked in the Warranty Department analysising all UK and a percentage of international Warranty Returns to improve Manufacturing of the product. I also did some dealer visits and vehicle investigations in my time aswell.

So basically, I know everything there needs to know about the Nissan K12 EPS System.

You are correct, you cannot fit a second hand unit to a vehicle because the system handshakes with a dongle to the BCM and restricts ignition on if the dongle does not match. I know people who have fitted second hand units to their vehicle and it's worked, but not sure how they did this (I do have my opionions how you could possible do this but wouldn't want to broadcast on an open forum - becuase I am not total convinced and never tried it). I don't think TRW ever released the knowhow on clearing the dongle, when I visited Nissan Technical Centre to do some testing on a vehicle - not even Nissan had the ability to clear the dongle on the EPS System.

Next Subject, Fault Codes. The System has many internal fault codes which only display to a handful of DTC on the vehical. If the system identfies a failure it will generate a internal fault code and reduce the asssistance to 0% by disengaging the moter relay for safey. On ignition cycle the fault will be cleared unless it's a hard failure and the fault code will regenerate. If the fault code is generated 3 times in a row then the system latches and generates a System latch and can only be cleared by a diagnostics machine over CAN. These fault codes are Level A, Level B and Level C failures within the system. Level A Failures are normally CAN Issus (Communication Protacol), Level B are hardware failures and Level C are Latch Faults.

During the production there were known hardware and software issues within the system which was resolved during manufacturing. Earlier Systems are more common to fail then later systems. Software failure are normally intermittent and fails but when cleared would normally not fail again.

The system is designed in 3 blocks, ECU, Motor and Torque Sensor. The Motor was manufactured by Globe Motors and are very reliable apart from the Relay that is fitted. The Torque Sensor is an optical system produced in a clean room environment and the ECU was manufactured internally by a sister plant. I wouldn't recommend anyone trying to repair or opening the system without knowning what they are doing. I have questions a few of the re-manufacturing companies that state they repair the systems asking what exactly do they repair (just out of interest) but never got a reply. I would really question their intentions because I know TRW would never release the source Code or Database Files for any external site to repair the EPS. I was working in Prague for 1 year to estblish a Re-Manufacturing process for the EPS Systems and to be honest, it never hit off due to safety and the manufacturing plant didn't want to release the source code - it's agood job I had all what I needed! TRW always said that no system would ever be released if a Failure ever occured regardless of cause; I remember we had a production failure where the test machine was created internal fault codes into the system and all the systems were scrapped (over 200).

The system works on the CAN System of the vehicle and transmit and receives data to and from the ECM, BCM etc.. The system can be interigated with TRW mapped databases and internal parameters can be monitored and configurated over the CANbus. This was never released (as I'm aware) to the general public or Nissan.

Unforntunatly TRW lost the contract for the K12 system in 2009 (I think - if I remember correctly) which was unforntunaity becuase by 2006+ the system was really good and I would recommend the system to anyone. I beleive Delphi now produce the system for the K13 and also a retro fit for the K12 for the TRW replacement. I left TRW in 2010 and went on to bigger and better things.. but I do still know alot about the system and could really help someone if needed with reading the internal fault codes and resetting the dongle if required.

Another thing that I didn't talk about - The system has diffenrent Tune data for different Car configurations, without reading my old notes this was, Perol, Diesal, Sport and C+C Model Range. The system has boost curves, self steering centring and all the good stuff which can be configured with the right tools.

As someone said above, the system does have 2 relays, These are actually called a Link relay and Motor Relay. The Motor Relay is to activate the motor, and to disable the 3-phase motor on failure if required. The Link relay is on the ECU.

I'm trying to answer all the questions above with alittle of information, faults can be caued due to the relays but it's just as likely to be an internal hardware failure. a spec of dust in the torque sensor or a software issue. As I said previously, the system has many faults ( i think around 130ish) and these are assigned to about 5 DTCs so therefore the below DTC might have 100's of root causes. i.e DTC 5606 might be due to the Motor Relay, or the FET Drive for the Mototr the hall sensor which monitor the Motor or the motor feedback circuit. So basically could be either Motor or ECU Fault - in Warranty we barely looked at the DTC unless the system had no internal fault codes because it never helped!

DTC Number Description
5601 Battery Voltage Fault
D000 CAN Bus Fault
5609 CAN Vehicle Speed Fault
5611 CAN RearGearEngaged Invalid
5603 EPS Transient Fault
5604 EPS Operation Fault – Torque Sensor
5606 EPS Operation Fault – Motor
5607 EPS Operation Fault – NVM
5608 EPS Operation Fault – ECU
5604 EPS Internal Fault – Torque Sensor
5606 EPS Internal Fault – Motor
5607 EPS Internal Fault – NVM
5608 EPS Internal Fault – ECU

If someone needs specific details then private message me and I'll try and help.

The TRW System does get some negative feedback - but to be honest I like it. I like it that much I have fitted it to my kit car, this maybe because I can get it working and do some fancy stuff with it - but it's worked really well..

I think I have answered as much as I can - my wife is giving me that look to get off my laptop.

If I can post other helpful stuff I will.

P.S I live in Birmingham - UK so if anyone is around I'm sure I can help. I actually went to a scrap yard yesterday and got 2 EPS off a Micra for spares for my kit Car, knowing if it fails it easier to chnage it. Only takes 10 minutes to remove the EPS (from a scrap car) the bottom of the dash does get in the way and I break it on the scrap car!!!

Hope it made sense and everyone gets alittle information.

Jason
 

frank

Club Member
if its anything like the vauxhall eps, the unit has to be divorced from the car (via obd) before its removed from the donor car
 
The EPS cannot be 'divorced' unless you have the OEM software and it can be done after the event of removing it aswell.

Jason.
 
Hey all,

Now I am on my laptop I can reply properly.

I used to work at the manufactures of ther EPS System (TRW Automotive), where I worked in the Warranty Department analysising all UK and a percentage of international Warranty Returns to improve Manufacturing of the product. I also did some dealer visits and vehicle investigations in my time aswell.

So basically, I know everything there needs to know about the Nissan K12 EPS System.

You are correct, you cannot fit a second hand unit to a vehicle because the system handshakes with a dongle to the BCM and restricts ignition on if the dongle does not match. I know people who have fitted second hand units to their vehicle and it's worked, but not sure how they did this (I do have my opionions how you could possible do this but wouldn't want to broadcast on an open forum - becuase I am not total convinced and never tried it). I don't think TRW ever released the knowhow on clearing the dongle, when I visited Nissan Technical Centre to do some testing on a vehicle - not even Nissan had the ability to clear the dongle on the EPS System.

Next Subject, Fault Codes. The System has many internal fault codes which only display to a handful of DTC on the vehical. If the system identfies a failure it will generate a internal fault code and reduce the asssistance to 0% by disengaging the moter relay for safey. On ignition cycle the fault will be cleared unless it's a hard failure and the fault code will regenerate. If the fault code is generated 3 times in a row then the system latches and generates a System latch and can only be cleared by a diagnostics machine over CAN. These fault codes are Level A, Level B and Level C failures within the system. Level A Failures are normally CAN Issus (Communication Protacol), Level B are hardware failures and Level C are Latch Faults.

During the production there were known hardware and software issues within the system which was resolved during manufacturing. Earlier Systems are more common to fail then later systems. Software failure are normally intermittent and fails but when cleared would normally not fail again.

The system is designed in 3 blocks, ECU, Motor and Torque Sensor. The Motor was manufactured by Globe Motors and are very reliable apart from the Relay that is fitted. The Torque Sensor is an optical system produced in a clean room environment and the ECU was manufactured internally by a sister plant. I wouldn't recommend anyone trying to repair or opening the system without knowning what they are doing. I have questions a few of the re-manufacturing companies that state they repair the systems asking what exactly do they repair (just out of interest) but never got a reply. I would really question their intentions because I know TRW would never release the source Code or Database Files for any external site to repair the EPS. I was working in Prague for 1 year to estblish a Re-Manufacturing process for the EPS Systems and to be honest, it never hit off due to safety and the manufacturing plant didn't want to release the source code - it's agood job I had all what I needed! TRW always said that no system would ever be released if a Failure ever occured regardless of cause; I remember we had a production failure where the test machine was created internal fault codes into the system and all the systems were scrapped (over 200).

The system works on the CAN System of the vehicle and transmit and receives data to and from the ECM, BCM etc.. The system can be interigated with TRW mapped databases and internal parameters can be monitored and configurated over the CANbus. This was never released (as I'm aware) to the general public or Nissan.

Unforntunatly TRW lost the contract for the K12 system in 2009 (I think - if I remember correctly) which was unforntunaity becuase by 2006+ the system was really good and I would recommend the system to anyone. I beleive Delphi now produce the system for the K13 and also a retro fit for the K12 for the TRW replacement. I left TRW in 2010 and went on to bigger and better things.. but I do still know alot about the system and could really help someone if needed with reading the internal fault codes and resetting the dongle if required.

Another thing that I didn't talk about - The system has diffenrent Tune data for different Car configurations, without reading my old notes this was, Perol, Diesal, Sport and C+C Model Range. The system has boost curves, self steering centring and all the good stuff which can be configured with the right tools.

As someone said above, the system does have 2 relays, These are actually called a Link relay and Motor Relay. The Motor Relay is to activate the motor, and to disable the 3-phase motor on failure if required. The Link relay is on the ECU.

I'm trying to answer all the questions above with alittle of information, faults can be caued due to the relays but it's just as likely to be an internal hardware failure. a spec of dust in the torque sensor or a software issue. As I said previously, the system has many faults ( i think around 130ish) and these are assigned to about 5 DTCs so therefore the below DTC might have 100's of root causes. i.e DTC 5606 might be due to the Motor Relay, or the FET Drive for the Mototr the hall sensor which monitor the Motor or the motor feedback circuit. So basically could be either Motor or ECU Fault - in Warranty we barely looked at the DTC unless the system had no internal fault codes because it never helped!

DTC Number Description
5601 Battery Voltage Fault
D000 CAN Bus Fault
5609 CAN Vehicle Speed Fault
5611 CAN RearGearEngaged Invalid
5603 EPS Transient Fault
5604 EPS Operation Fault – Torque Sensor
5606 EPS Operation Fault – Motor
5607 EPS Operation Fault – NVM
5608 EPS Operation Fault – ECU
5604 EPS Internal Fault – Torque Sensor
5606 EPS Internal Fault – Motor
5607 EPS Internal Fault – NVM
5608 EPS Internal Fault – ECU

If someone needs specific details then private message me and I'll try and help.

The TRW System does get some negative feedback - but to be honest I like it. I like it that much I have fitted it to my kit car, this maybe because I can get it working and do some fancy stuff with it - but it's worked really well..

I think I have answered as much as I can - my wife is giving me that look to get off my laptop.

If I can post other helpful stuff I will.

P.S I live in Birmingham - UK so if anyone is around I'm sure I can help. I actually went to a scrap yard yesterday and got 2 EPS off a Micra for spares for my kit Car, knowing if it fails it easier to chnage it. Only takes 10 minutes to remove the EPS (from a scrap car) the bottom of the dash does get in the way and I break it on the scrap car!!!

Hope it made sense and everyone gets alittle information.

Jason
Hi Jason, i fitted a secondhand unit to my 2005 k12 micra, since fitting it the steering is back working perfect but my airbag light is flashing and sometimes the immobiliser light comes on but the car still runs, i had a friend who is a nissan mechanic plug it in to a laptop and he told me i had a wire disconnected but i rechecked all the wiring today, it was perfect but still have the problem, thanks in advance for any help or advice
 
Hey all,

Now I am on my laptop I can reply properly.

I used to work at the manufactures of ther EPS System (TRW Automotive), where I worked in the Warranty Department analysising all UK and a percentage of international Warranty Returns to improve Manufacturing of the product. I also did some dealer visits and vehicle investigations in my time aswell.

So basically, I know everything there needs to know about the Nissan K12 EPS System.

You are correct, you cannot fit a second hand unit to a vehicle because the system handshakes with a dongle to the BCM and restricts ignition on if the dongle does not match. I know people who have fitted second hand units to their vehicle and it's worked, but not sure how they did this (I do have my opionions how you could possible do this but wouldn't want to broadcast on an open forum - becuase I am not total convinced and never tried it). I don't think TRW ever released the knowhow on clearing the dongle, when I visited Nissan Technical Centre to do some testing on a vehicle - not even Nissan had the ability to clear the dongle on the EPS System.

Next Subject, Fault Codes. The System has many internal fault codes which only display to a handful of DTC on the vehical. If the system identfies a failure it will generate a internal fault code and reduce the asssistance to 0% by disengaging the moter relay for safey. On ignition cycle the fault will be cleared unless it's a hard failure and the fault code will regenerate. If the fault code is generated 3 times in a row then the system latches and generates a System latch and can only be cleared by a diagnostics machine over CAN. These fault codes are Level A, Level B and Level C failures within the system. Level A Failures are normally CAN Issus (Communication Protacol), Level B are hardware failures and Level C are Latch Faults.

During the production there were known hardware and software issues within the system which was resolved during manufacturing. Earlier Systems are more common to fail then later systems. Software failure are normally intermittent and fails but when cleared would normally not fail again.

The system is designed in 3 blocks, ECU, Motor and Torque Sensor. The Motor was manufactured by Globe Motors and are very reliable apart from the Relay that is fitted. The Torque Sensor is an optical system produced in a clean room environment and the ECU was manufactured internally by a sister plant. I wouldn't recommend anyone trying to repair or opening the system without knowning what they are doing. I have questions a few of the re-manufacturing companies that state they repair the systems asking what exactly do they repair (just out of interest) but never got a reply. I would really question their intentions because I know TRW would never release the source Code or Database Files for any external site to repair the EPS. I was working in Prague for 1 year to estblish a Re-Manufacturing process for the EPS Systems and to be honest, it never hit off due to safety and the manufacturing plant didn't want to release the source code - it's agood job I had all what I needed! TRW always said that no system would ever be released if a Failure ever occured regardless of cause; I remember we had a production failure where the test machine was created internal fault codes into the system and all the systems were scrapped (over 200).

The system works on the CAN System of the vehicle and transmit and receives data to and from the ECM, BCM etc.. The system can be interigated with TRW mapped databases and internal parameters can be monitored and configurated over the CANbus. This was never released (as I'm aware) to the general public or Nissan.

Unforntunatly TRW lost the contract for the K12 system in 2009 (I think - if I remember correctly) which was unforntunaity becuase by 2006+ the system was really good and I would recommend the system to anyone. I beleive Delphi now produce the system for the K13 and also a retro fit for the K12 for the TRW replacement. I left TRW in 2010 and went on to bigger and better things.. but I do still know alot about the system and could really help someone if needed with reading the internal fault codes and resetting the dongle if required.

Another thing that I didn't talk about - The system has diffenrent Tune data for different Car configurations, without reading my old notes this was, Perol, Diesal, Sport and C+C Model Range. The system has boost curves, self steering centring and all the good stuff which can be configured with the right tools.

As someone said above, the system does have 2 relays, These are actually called a Link relay and Motor Relay. The Motor Relay is to activate the motor, and to disable the 3-phase motor on failure if required. The Link relay is on the ECU.

I'm trying to answer all the questions above with alittle of information, faults can be caued due to the relays but it's just as likely to be an internal hardware failure. a spec of dust in the torque sensor or a software issue. As I said previously, the system has many faults ( i think around 130ish) and these are assigned to about 5 DTCs so therefore the below DTC might have 100's of root causes. i.e DTC 5606 might be due to the Motor Relay, or the FET Drive for the Mototr the hall sensor which monitor the Motor or the motor feedback circuit. So basically could be either Motor or ECU Fault - in Warranty we barely looked at the DTC unless the system had no internal fault codes because it never helped!

DTC Number Description
5601 Battery Voltage Fault
D000 CAN Bus Fault
5609 CAN Vehicle Speed Fault
5611 CAN RearGearEngaged Invalid
5603 EPS Transient Fault
5604 EPS Operation Fault – Torque Sensor
5606 EPS Operation Fault – Motor
5607 EPS Operation Fault – NVM
5608 EPS Operation Fault – ECU
5604 EPS Internal Fault – Torque Sensor
5606 EPS Internal Fault – Motor
5607 EPS Internal Fault – NVM
5608 EPS Internal Fault – ECU

If someone needs specific details then private message me and I'll try and help.

The TRW System does get some negative feedback - but to be honest I like it. I like it that much I have fitted it to my kit car, this maybe because I can get it working and do some fancy stuff with it - but it's worked really well..

I think I have answered as much as I can - my wife is giving me that look to get off my laptop.

If I can post other helpful stuff I will.

P.S I live in Birmingham - UK so if anyone is around I'm sure I can help. I actually went to a scrap yard yesterday and got 2 EPS off a Micra for spares for my kit Car, knowing if it fails it easier to chnage it. Only takes 10 minutes to remove the EPS (from a scrap car) the bottom of the dash does get in the way and I break it on the scrap car!!!

Hope it made sense and everyone gets alittle information.

Jason

Great technical information. It's worse than i expected with the Dongle rubbish. Found out today when replacing a scrap yard unit the ignition no longer starts the car, thought it might be an address thing, but if cannot be set easily then it looks like, game over...
Question, can you get the BCM dongle from the dona car, to make it work?
 
got sorted:- found the code lock chip and swapped it from the old unit to the new unit.
yes ignition starts now ..... the old ic had the fault locked out from the original unit, so PS light still on.
Then had to go to proper diagnostic centre, who did the reset and wheel alignment calibration.

I'm based in Birmingham

Attached is picture of the location of the code IC 'ST24C16'
 

Attachments

Last edited:
got sorted:- found the code lock chip and swapped it from the old unit to the new unit.
yes ignition starts now ..... the old ic had the fault locked out from the original unit, so PS light still on.
Then had to go to proper diagnostic centre, who did the reset and wheel alignment calibration.

I'm based in Birmingham

Attached is picture of the location of the code IC 'ST24C16'

Looks and sounds like your “ Jobs a Goodun” over three months to resolve K12 EPS most challenging technical problem that usually results in the vehicle being an economic write off.

Long may it continue & an idiots guide road map to your solution would be much appreciated by the many yet to face this K12 issue?
 
Looks and sounds like your “ Jobs a Goodun” over three months to resolve K12 EPS most challenging technical problem that usually results in the vehicle being an economic write off.

Long may it continue & an idiots guide road map to your solution would be much appreciated by the many yet to face this K12 issue?

it didn't take that long. but was involved.
1 st get a suitable unit from scap yard paid £25 obviously no way of knowing if it works
lashed up on passenger seat to check if it works, a good sign is when try ignition it WILL NOT fire the engine because of the Code thing. But what the test does is the unit gives a good Relay click sound as on ours the relay had locked out due to the fault 3 trys and your out software, mentioned in huttojb post above.
so now have a potential good unit. and original broken unit.
see attached pdf open the square box part with PCB exposed in the PDF locate the 8 pin IC ST24C16.
Then simply transfer the 8 pin IC from the old unit to the new unit, Need a half decent hot air rework unit to do this.
Don't worry if the odd pad lets go checked the data sheet on this ic and only 5 of the 8 pins are needed.
Then when done do the passenger seat check and now the car ignition should fire up Ok as the code IC is now on the new unit.
But even though the new unit did work, now with the new code IC installed it has the code for the software lock out so it no longer works...
It needs a proper diagnostic unit to reset the codes and do a steering calibration. That cost us £40.
 

Attachments

Hey pleh,

I live in birmingham and if you popped round I would of cleared the security feature for you in 2 mins...

The IC you removed is the NVM Memory chip (IC5) on the circuit, look at schmatic layout attached. I would not advise your actions, even know it worked in your instance but it has alot of risk. The NVM Memory also stores ECU trim data for the unit, during the ECU manufacturing process the ECU is calibrated because of variations within the ECU. Then during the System manfacturing the system is calibrated with the motor torque, motor trim, motor demand and all these values are stored within the NVM for EPS operation. every unit is differnet, every ECU is different so therefore every NVM memory is different. So like i said, because it's a safety critical devise doing this would not be recommended especially if something wrong happens on the road with irratic steering because of your actions.

Next issue is, to take the ECU cover off you are required to remove the column, again during manufacturing the column assembly is attached with no side loads as this will effect input torque and any side load when the column is torqued by the 4 screws will cause potetntial steering issues.

I would seriously recommend getting another EPS from the scrap yard, pop round and i'll sort it for you. wouldn't want anything to happen.

Jason
 

Attachments

I have a 2005 K12 with the same issue.

Whats my most cost effective option?

Used unit? (£75-£150ish) Can these be fitted DIY?

Refurbished?

Or get my own unit reconditioned?
 
Sheets,

Like I said above, I wouldn’t recommended the solution suggested above. A used unit cost £40+ from a scrap yard but it will not be paired with your car and therefore you’ll have NATS issues. It is quite simple to remove and replace the EPS but you need to get it paired.

Not sure what the refurbish ones are like and don’t really trust them.

Would you be interested in sending me your one (at your cost), I’ll check it and either send the original one back with it cleared or send one from the scrap yard which can pair to your car if the original one Has a hard fault.

Message me and we can discuss.

Jason.
 
Sheets,

Like I said above, I wouldn’t recommended the solution suggested above. A used unit cost £40+ from a scrap yard but it will not be paired with your car and therefore you’ll have NATS issues. It is quite simple to remove and replace the EPS but you need to get it paired.

Not sure what the refurbish ones are like and don’t really trust them.

Would you be interested in sending me your one (at your cost), I’ll check it and either send the original one back with it cleared or send one from the scrap yard which can pair to your car if the original one Has a hard fault.

Message me and we can discuss.

Jason.
Big thankyou to Jason for sorting my EPS problem out - used unit supplied with the Dongle issue dealt with so it goes straight in the car with no need for a dealer visit. Works and drives great with no fault codes.
Definitely the man to see about this. Really cost effective compared to the ridiculous prices quoted by my Nissan dealer!
 
Big thankyou to Jason for sorting my EPS problem out - used unit supplied with the Dongle issue dealt with so it goes straight in the car with no need for a dealer visit. Works and drives great with no fault codes.
Definitely the man to see about this. Really cost effective compared to the ridiculous prices quoted by my Nissan dealer!

Looks like a successful good work around guys and the first ESP replacement DIY solution on the MSC?

Now were curious & looking for simplified write up guide so that competent DIY persons could similarly economically reliably replicate the job of K12 ESP replacement /calibrating/recoding? ;)
 
Removing/refitting the EPS/steering column is easy.
Took me about 90 minutes to remove as I've never touched one before but less than an hour to refit.
I could do it next time in 30 minutes now I know where the screws /bolts are, and which bits of trim need to come off.

Don't think the average DIYer can do the coding bit though without the specialist software. It's important that the steering column is set via the software to the correct position, in addition to the dongle issue.
Speak to Jason though if you want this sorting as he's the software expert!
 
Hey all,

Now I am on my laptop I can reply properly.

I used to work at the manufactures of ther EPS System (TRW Automotive), where I worked in the Warranty Department analysising all UK and a percentage of international Warranty Returns to improve Manufacturing of the product. I also did some dealer visits and vehicle investigations in my time aswell.

So basically, I know everything there needs to know about the Nissan K12 EPS System.

You are correct, you cannot fit a second hand unit to a vehicle because the system handshakes with a dongle to the BCM and restricts ignition on if the dongle does not match. I know people who have fitted second hand units to their vehicle and it's worked, but not sure how they did this (I do have my opionions how you could possible do this but wouldn't want to broadcast on an open forum - becuase I am not total convinced and never tried it). I don't think TRW ever released the knowhow on clearing the dongle, when I visited Nissan Technical Centre to do some testing on a vehicle - not even Nissan had the ability to clear the dongle on the EPS System.

Next Subject, Fault Codes. The System has many internal fault codes which only display to a handful of DTC on the vehical. If the system identfies a failure it will generate a internal fault code and reduce the asssistance to 0% by disengaging the moter relay for safey. On ignition cycle the fault will be cleared unless it's a hard failure and the fault code will regenerate. If the fault code is generated 3 times in a row then the system latches and generates a System latch and can only be cleared by a diagnostics machine over CAN. These fault codes are Level A, Level B and Level C failures within the system. Level A Failures are normally CAN Issus (Communication Protacol), Level B are hardware failures and Level C are Latch Faults.

During the production there were known hardware and software issues within the system which was resolved during manufacturing. Earlier Systems are more common to fail then later systems. Software failure are normally intermittent and fails but when cleared would normally not fail again.

The system is designed in 3 blocks, ECU, Motor and Torque Sensor. The Motor was manufactured by Globe Motors and are very reliable apart from the Relay that is fitted. The Torque Sensor is an optical system produced in a clean room environment and the ECU was manufactured internally by a sister plant. I wouldn't recommend anyone trying to repair or opening the system without knowning what they are doing. I have questions a few of the re-manufacturing companies that state they repair the systems asking what exactly do they repair (just out of interest) but never got a reply. I would really question their intentions because I know TRW would never release the source Code or Database Files for any external site to repair the EPS. I was working in Prague for 1 year to estblish a Re-Manufacturing process for the EPS Systems and to be honest, it never hit off due to safety and the manufacturing plant didn't want to release the source code - it's agood job I had all what I needed! TRW always said that no system would ever be released if a Failure ever occured regardless of cause; I remember we had a production failure where the test machine was created internal fault codes into the system and all the systems were scrapped (over 200).

The system works on the CAN System of the vehicle and transmit and receives data to and from the ECM, BCM etc.. The system can be interigated with TRW mapped databases and internal parameters can be monitored and configurated over the CANbus. This was never released (as I'm aware) to the general public or Nissan.

Unforntunatly TRW lost the contract for the K12 system in 2009 (I think - if I remember correctly) which was unforntunaity becuase by 2006+ the system was really good and I would recommend the system to anyone. I beleive Delphi now produce the system for the K13 and also a retro fit for the K12 for the TRW replacement. I left TRW in 2010 and went on to bigger and better things.. but I do still know alot about the system and could really help someone if needed with reading the internal fault codes and resetting the dongle if required.

Another thing that I didn't talk about - The system has diffenrent Tune data for different Car configurations, without reading my old notes this was, Perol, Diesal, Sport and C+C Model Range. The system has boost curves, self steering centring and all the good stuff which can be configured with the right tools.

As someone said above, the system does have 2 relays, These are actually called a Link relay and Motor Relay. The Motor Relay is to activate the motor, and to disable the 3-phase motor on failure if required. The Link relay is on the ECU.

I'm trying to answer all the questions above with alittle of information, faults can be caued due to the relays but it's just as likely to be an internal hardware failure. a spec of dust in the torque sensor or a software issue. As I said previously, the system has many faults ( i think around 130ish) and these are assigned to about 5 DTCs so therefore the below DTC might have 100's of root causes. i.e DTC 5606 might be due to the Motor Relay, or the FET Drive for the Mototr the hall sensor which monitor the Motor or the motor feedback circuit. So basically could be either Motor or ECU Fault - in Warranty we barely looked at the DTC unless the system had no internal fault codes because it never helped!

DTC Number Description
5601 Battery Voltage Fault
D000 CAN Bus Fault
5609 CAN Vehicle Speed Fault
5611 CAN RearGearEngaged Invalid
5603 EPS Transient Fault
5604 EPS Operation Fault – Torque Sensor
5606 EPS Operation Fault – Motor
5607 EPS Operation Fault – NVM
5608 EPS Operation Fault – ECU
5604 EPS Internal Fault – Torque Sensor
5606 EPS Internal Fault – Motor
5607 EPS Internal Fault – NVM
5608 EPS Internal Fault – ECU

If someone needs specific details then private message me and I'll try and help.

The TRW System does get some negative feedback - but to be honest I like it. I like it that much I have fitted it to my kit car, this maybe because I can get it working and do some fancy stuff with it - but it's worked really well..

I think I have answered as much as I can - my wife is giving me that look to get off my laptop.

If I can post other helpful stuff I will.

P.S I live in Birmingham - UK so if anyone is around I'm sure I can help. I actually went to a scrap yard yesterday and got 2 EPS off a Micra for spares for my kit Car, knowing if it fails it easier to chnage it. Only takes 10 minutes to remove the EPS (from a scrap car) the bottom of the dash does get in the way and I break it on the scrap car!!!

Hope it made sense and everyone gets alittle information.

Jason
Hi Jason,
I have just bought a k12 and the electric PS is not working. Will be in Birmingham this weekend if you can help please
Thanks
Dee
 
Can have a look and have a few replacements if needed. Pm me.
Hi, no idea how to pm you, but my nissan micra cc 56 plate has developed this fault for the 2nd time. I had it repaired by a company that reconditions the systems, but that was about 5 years ago, and I have lost the paperwork, else I would go back to them. They were somewhere between Manchester and here, Barnsley. I have searched google cos thats where I found them before. Anyway, I am not adverse to driving to Birmingham area if you can furnish a unit and replace mine, I have developed strong arms :) I am driving to London on Monday and can stop on the way, or, I can just drive to you.
 
Hi, no idea how to pm you, but my nissan micra cc 56 plate has developed this fault for the 2nd time. I had it repaired by a company that reconditions the systems, but that was about 5 years ago, and I have lost the paperwork, else I would go back to them. They were somewhere between Manchester and here, Barnsley. I have searched google cos thats where I found them before. Anyway, I am not adverse to driving to Birmingham area if you can furnish a unit and replace mine, I have developed strong arms :) I am driving to London on Monday and can stop on the way, or, I can just drive to you.
I have pm’ed you
 
Hey pleh,

I live in birmingham and if you popped round I would of cleared the security feature for you in 2 mins...

The IC you removed is the NVM Memory chip (IC5) on the circuit, look at schmatic layout attached. I would not advise your actions, even know it worked in your instance but it has alot of risk. The NVM Memory also stores ECU trim data for the unit, during the ECU manufacturing process the ECU is calibrated because of variations within the ECU. Then during the System manfacturing the system is calibrated with the motor torque, motor trim, motor demand and all these values are stored within the NVM for EPS operation. every unit is differnet, every ECU is different so therefore every NVM memory is different. So like i said, because it's a safety critical devise doing this would not be recommended especially if something wrong happens on the road with irratic steering because of your actions.

Next issue is, to take the ECU cover off you are required to remove the column, again during manufacturing the column assembly is attached with no side loads as this will effect input torque and any side load when the column is torqued by the 4 screws will cause potetntial steering issues.

I would seriously recommend getting another EPS from the scrap yard, pop round and i'll sort it for you. wouldn't want anything to happen.

Jason
Hi Jason, if I bring such a 2nd hand unit to Birmingham, would you have a look at it?
 
Please can you help I recently bought a second hand eps to replace the original one that developed a fault. PS light was one but that is now cleared with the new one one on but the NATS light comes in after a few minutes and stays on. What should I do thanks
 
Yeah. I have replied on the private convo you started. Don’t get me wrong their seems to be ways to do this, none I recommend because of the other calibration data but it’s an easy job.
 
Hi thanks for replying me. When I carried the diagnostics it gave an error code of U1001. Do you think you will be able to reprogramme it thanks if so I can drive down tomorrow
 
Like I explained to you before the power steering works now but after a couple of minutes the car symbol with a car in between illuminates on the dashboard and stays that way until the car is switched off and then it goes away
 
That message is something to do with CAN Communication. It might be throwing that message because it cannot read something or getting a bad message.

Who fitted the eps system?
 
Another happy forum member; 2 issues on the car.... the system was fitted with the staight ahead not in the middle causing a failure. And unit was still paired to the old vehicle.
 
Another happy forum member; 2 issues on the car.... the system was fitted with the staight ahead not in the middle causing a failure. And unit was still paired to the old vehicle.
Good to see another K12 saved from the EPS planned obsolescence economic write off syndrome. Many more, way to go? :)
 
Hi All,

I have same PS issue. Today I used OBD reader scanner which I bought from ebay but it does not show any fault codes. why is that ?

And I am in edinburgh, I wonder what options I have to fix this issue ?

Many thanks Guys
 
My Obd reader did not connect tried a few times with a phone but not a laptop as yet still not sure if its a faulty unit or just my error when connecting BT.
 
ok so here is update. My cheap ebay obd reader did not detect any codes.
I took car to garage, and my friend used his £3000 OBD scanner which brought up two codes.

C1604 = Torque sensor incorporated in column assembly is malfunctioning
C1608 = Control Unit is malfunctioning

He has cleared the codes and all working fine now. PS light has gone off and power steering back to normal.

Now big question is, for how long ? :)
 
Good luck. May last for a few months. The torque sensor is an optical sensor and was manufactured in a clean room environment. And if my memory is correct, if there is any dust greater the 40 microns it can cause a failure. But if the dust moves it will then work once the faults are cleared. There is only a small window of operation so as long as the contamination particles don’t pass over the operation window it won’t trip again.

Obviously with the DTC code doesn’t give you exactly the internal fault codes, so there was about 20 internal fault codes relate to the torque sensor, from dust in the system to the disc falling off. 95% of the time it was contamination.
I do have 3 units in but hopefully you will be fine. I would replace the systems personally, especially on a torque sensor issue that can happen on speed. I did some testing with fault insertion on the MIcra and it’s not nice when the system trips at any kind of speed.

Usually people wait till it’s a hard fault, so you know where I am if you need me.

Jason.
 
Good luck. May last for a few months. The torque sensor is an optical sensor and was manufactured in a clean room environment. And if my memory is correct, if there is any dust greater the 40 microns it can cause a failure. But if the dust moves it will then work once the faults are cleared. There is only a small window of operation so as long as the contamination particles don’t pass over the operation window it won’t trip again.

Obviously with the DTC code doesn’t give you exactly the internal fault codes, so there was about 20 internal fault codes relate to the torque sensor, from dust in the system to the disc falling off. 95% of the time it was contamination.
I do have 3 units in but hopefully you will be fine. I would replace the systems personally, especially on a torque sensor issue that can happen on speed. I did some testing with fault insertion on the MIcra and it’s not nice when the system trips at any kind of speed.

Usually people wait till it’s a hard fault, so you know where I am if you need me.

Jason.
Thanks.

pitty you are so far away in Birmingham. I am in edinburgh :(
 
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