Newbie needing technical help please!!!

[MiracleBoy]

Hello,

My K12 Micra is showing the following codes intermitently & going into limp home mode. P1171 & P1229 & P2138. The codes usually appear 2 at a time, i.e. P1171 & P1229 or P1229 & P2138. When the car going into limp mode, it starts revving up by itself, as if I was blipping the throttle once every second or so, but the throttle is fully released..

I've had the throttle body replaced with NEW one, but this hasn't solved the problem. I've metered out all the conections in the wiring harness to the TPS (Throttle position Sensor) & all seems to be fine. I have also noticed that the car runs without fault in warm weather, but in the evenings when it's cooler, the fault happens very frequently. Could this issue be related to the MAP sensor or the O2 sensors?? Can you please help!!

Thanks!!

MB

 

[jowley]

have you checked all the fuse it sounds like a power supply fault or a bad earth u need to test power to the maf/map sensor an throttle unit

 

[MiracleBoy]

have you checked all the fuse it sounds like a power supply fault or a bad earth u need to test power to the maf/map sensor an throttle unit

Hi Jowley,

Thanks for your Reply!! Much appreciated!!

I've checked the harness to the Throttle position sensor & to the MAP sensor. And I've checked the ALL fuses. I'm getting 5v from the power supply pins on the ECU to both the MAP Sensor & the TP sensor, so that seems to check out o.k.

The MAP sensor DTC 1171 has stopped happening. Now I'm getting just P1229, or P1229 + P2122 and/or P2138, all of which are TPS error codes. (But like I said, I've had the whole throttle body replaced already!!)

I've noticed now that most of the time the car runs o.k. during the day. But at night with the lights running it's much more likely to happen. When I clear the DTC's at night it's only a matter if seconds after I drive off again that the MI light comes back on & I'm back to square one again.

Tomorrow night I'm going to clean up as many earths as I can find in the engine bay & see if that helps.

It seems signifficant that the DTC's happen more often when there is a greater load on the Power supply system with the lights being on.

As far as I can tell, the ECU (ECM) supplys power to both the TPS & the MAP sensor. I just hope that my ECU isn't faulty as that would be a rather costly thing to replace!!!

I'll let you know how I get on!!

Thanks again!!

MB

 

[jowley]

the alternator regulator may be faulty its desiged to give more power to the engine under load. test the alternator . first just have the engine running nothing else on an measure the voltage at fast idle 2000rpm. then switch everything on lights heated window fans everything possible and test the voltage again both times they should be around 14volts

 

[MiracleBoy]

Hi Jowley,

I spent the evening cleaning up every earth I could get access to & cleaned tham all up. Most seemed just fine anyway but a few were a bid iffy looking. I also unplugged all the connectors in the Inteligent Power Distribution Module (IPDM) & opened it up for a look see, but it's pretty well sealed unit so couldn't really check anything. I put the whole lot back together again & went for a run with the lights on etc and at first all seemed fine. But after about 30 mins worth of driving around the faults came back again.

DTC's P1229, P2122, P2138 and P0107 came up one as well. All power issues of the "low input" kind.

I'll have a go at when you've suggested tomorrow night & let you know how I get on.

Thanks again for you advise.

Cheers
MB