K11 1.4 CGA3DE - P0171

Hey guys, about 6 months ago I became the proud owner of a k11 Micra in 5 door 1.4 auto form. It had only done about 4500 genuine miles and although was a pretty penny to buy, I couldn't resist the charm and had to get it!
Needless to say it's cracking car and great fun.
Yesterday while on a trip to the petrol station the eml light lot up and my torque app diagnosed it as a p0171 system lean bank1. I have done some reading around and it appears to be a maf/oxygen sensor that needs replacing? Anyone have any experience with this particular code?
Thanks in advance!
 
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Hey guys, I cleaned out the MAF sensor over xmas and this seemed to sort it.
However, it came back over the weekend! Is there a part number for the lambda sensor? Also, how easy is it to change? I'm a bit of a noob when it comes to this sort of stuff but willing to get my hands dirty!
Thanks
 
I use the torque android app along with a bluetooth dongle. It shows both lamdas and gives voltage output graphs for each one side by side. Along with the other sensors available it's a great app for diagnostics.
 
Oh the cost was £2.95 for the app and £4.99 for the dongle. You can't beat that for self diagnostics. You can even keep the dongle connected and have your phone as extra dials. If that's your thing.
 
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Hey guys, me again!
I have the torque app and dongle, had it plugged in since I bought it and that's what gave me the error code. Can you point me in the direction of which sensors to look at on the torque app?
Just took it to my local as I haven't fixed it yet and he looked at the lambda sensor. Says he hasn't seen one like it before!
It looks like this,
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Any ideas?
 
That's the standard 4 wire lambda. On the real time info screen long press and chose graph. Scroll down to o2 bank 1 sensor 1. Sensor 2 is the one after the cat. I usually put both graphs up and rev the car to around 2k. First sensor should look like a sine wave ish. Second should be a straight ish line.
 
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Ok cool, thanks for the input guys :)
Which one is the second lambda?
Don't think that there is a problem with the exhaust. Just had the mid section replaced as it was a bit rattly. The eml light was present both before and after that.
Apologies if I'm coming across as a bit of a noob, still learning!
 
Its in the downpipe part of the exhaust round about where the passengers feet would be. It could be shrouded by the heatshield if you still have that fitted.
 
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Excellent, I will Jack it up and have a look, would it be easy to change? Assume just need to remove heat shield, unscrew old one and pop new one in?
Would you be able to link the specific sensor needed? A quick Google search shows loads of different sensors. I assume this is the post cat sensor?
Thanks again! :) (and apologies again for all the questions!) ;)
 
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Quality! Second one deffo looks like a duffer! Are they the same sensor? So I can swap to see if that fixes it? I will try it out tomorrow if so! Thanks again for all your input gents :)
 
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Oh dear! Like I said, don't mind getting my hands dirty but am a bit of a noob! Is it just a case of unscrewing them after removing heat shield?
 
Yes you just unscrew them. 22mm iirc. They're awkward due to the fact they seize up due to where they are. Also those heatshield bolts can be seize in also. You don't need that heatshield underneath the car so it doesn't matter if you break it whilst removing it.
 
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Hey guys, me again!
So I jacked up the car looking to swap both the sensors and after much swearing came up with this. Few noob tips for anyone looking at this : I managed to do it without removing the heat shield underneath. Just worked around it. Also, when unscrewing or screwing back the sensor, before hand give it as many turns as you can in the opposite direction, will save a lot of time as it spins itself in/out.
Same as before 2k rpm
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Also, a quick comparison between the 2. Post cat (underneath the car) on top.
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So the question remains. Do I change the post cat lambda? If so what's the part number?
I noticed the engine was struggling to rev and almost spluttering recently, even more so after I did this. Have a look here, sorry about the exhaust buffeting the camera!
 
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That's what I am thinking. Just swapped it back and the engine isn't revving freely at all :(
I think the best bet would be to replace them both. On the plus side it sailed through mot and emissions were bang on!
Would you or anyone else know the part numbers for both lambda 's?
Thanks again for all the help!
 
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Ok just for extra clarity I took a video of the torque app while at Idle, 2k revs and random full throttle blips.
Hope someone can make sense of what's going on! (also no idea why I sound like a 12 year old! I promise I'm not!!!)
 
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Not sure if anyone is still keeping up with this thread but I just splashed out on 2 new lambda sensors to see if it would cure the problem and unfortunately it's the same. And by the same I mean quite bad. Over the past few weeks the car is really struggling to generate power and almost dies on full throttle. The sensor readings with the new lambda sensors are below.
0-30seconds - idle
30-55seconds 2krpm
1:10 full throttle then idle
 
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Ok so I unplugged the MAF and everything was sweet as a nut. Long story short, got a brand new MAF for £70 (I know) and whacked it in. All is well.
Thanks for all your help guys. Going to drive down south on a long motorway run so will see if it plays up again. If you don't hear from me it's fixed!
 
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:mad::mad::mad:

So the EML light came on today again. Don't get why. Car running fine. Getting bored of this already. Both lambda's and maf been changed. What next?
 
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Not really looked at the cat to be honest. What would I check? Looks good as new? How do I test the other sensors you mention? Fouling sensor? Over fuel sensor? Sorry for the questions, trying to learn as I go along!
 
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I'm going to try cleaning the MAF sensor and it's wires and everything around it with carb cleaner. If that doesn't help I'm stuck. :(
 
Maf cleaner. Not carb cleaner. Also make sure you've got the wire mesh and black plastic air straightener, chip cutter looking thing on top of the throttle body. On the second facelifts without these ecu faults will be registered.
 
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Will have a stab at this in the morning. Ordered some bits from Halfords so will let you know how I get on! Thanks again for all the pointers :D
 
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So I cleaned the MAF sensor with MAF cleaner (electrical contact cleaner?) from Halfords which smells remarkably like isopropyl alcohol and the car fired up fine and revs freely. I also cleaned the throttle body and it's surrounding areas with carb cleaner and checked the air filter and the area around there. It's all clean as a whistle!
I haven't managed to run it for long enough to see if the eml will light up again but I hope this has sorted it!
The sensor read out looks much better now!
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Thanks again, and you will no doubt be hearing from me if things go belly up again!
 
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Ah man, of I'd have known that I wouldn't have bought it! Got loads of it to clean thermal paste for my computer bits!!
Would you happen to know the screw size for the 2 torx screws holding the MAF in?
I need to replace them as they're pretty chewed up!
 
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So the drama continues......after cleaning the MAF it was all perfect, after a long run up to Yorkshire and then back down south, just as I'm pulling into home the EML light blinks on and once again I have a P0171 :(
Will clean the MAF again tomorrow but not sure how many more times I can take the screws in/out before the are properly bodged!
 
Just thinking, if cleaning the MAF helps as it seems to, is there something that's causing the MAF to foul? crappy air filter or I was thinking is the crank case breather bringing up some oil vapour (nope, that connects to the manifold on CG13, is it the same on CGAs? Yours is a relatively new engine correct? so shouldn't have much blowby anyway).

Reportedly oiled air filters can play havoc with hotwire MAF sensors you haven't got one do you?
 
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