Error Code P0171...does anyone know what it relates to?

Any poiinters on this one will be much appreciated, thanks.

Ok, so last week I fitted a new Bosch throttle body to my Micra 1.4, 2001 reg, and it's now running very nicely. It has a nice low tickover in place of the previous high and erratic one.

But a day or so after fitting the new throttle body, the engine light appeared on the dash. And it sat there, glowing at me. Little Bugger!

So I invested in a handheld OBD2 code reader from ECU Tools.

After plugging in the OBD 2 code reader, I found that I had one error code, a P0171, which, in the included book, relates to 'System too lean (Bank 1)'.

Could anyone tell me what 'bank 1' is, and what I might be able to do to cure the fault? It can't be too serious as the car runs very well.

Thanks for any pointers.

P0171 code is 'system to lean bank 1'

some things to check
-intake/exhaust leak
-AIR system
-MAF/VAF sensor
-fuel pressure/pump
-injectors
-HO2S

good luck
most times it is an air leak in the inlet manifold that causes this problem


OBD 2 is a universal coding system for all kinds of engines and vehicles..there is like 999 OBD codes... but not all are codes are used.. when they say bank 1 and bank 2 they are relating to V configuration engines...
straight configuration engines only have the one bank

thanks for that. I'll have a close look at these tomorrow, see if I can get to the root of the cause.

cool let me know how you go

Hi, Jay85.
Having cleared the error code, I have driven the car since and it has performed very well, and the light hasn't come on again.

Without disturbing anything, on Saturday, I had a good look around the engine bay, examining the throttle body connections and the exhaust.

Couldn't find anything obvious, so i'll keep using the car for now, but if the code returns, I'll start with refitting the throttle body with sealant and work from that.

I thought it might be dirty injectors, so I'm using a shot of reddex injector cleaner with each full tank for the next few tankfuls, just in case.

Thanks for your advice i'll keep it close to hand in case i need it again.

Hi All,

I know this post was some time ago, but in searching the forum for a solution to my problem this seems very similar.

To start: bought a 2001 Micra 1.4 activ, 44K miles from a salvage yard as an insurance write off - very little damage, just paintwork on the drivers side front and rear bumper and the panhard rod noticeably bent.

When driving the vehicle home, got an engine warning light on. Bought a diagnostic tester (if anyone in the Lowestoft area UK, needs to use a code reader, pls contact me) and this gave fault code P0171 - fuel system too lean. The car drives OK, feels a little sluggish (but hey it's only a 1.4). Tickover is hesistant when warm, but does not stall.

When I read the Micra forums messages this points to the Throttle body (TB). I found the fix posted on this site (well done guys) and proceeded to fix this yesterday. I discovered the the TB on this car is Bosch, so the solder fix is not possible.

My research has taken me thus far:
the bosch unit comprises of the main alloy housing plus three electical components: the air mass sensor, the idle sensor and the throttle positon sensor. These bosch units appear to be at least as faulty as the previous Mikuni TB - if you believe the websites selling replacements.

These parts are all available individually if you look around. So, rather than spend 200 sterling on replacing the whole thing is it worth replacing individual items? If so, which is best to go for first? Air mass sensor?

Do you think I'm on the right track or am I missing something like a simple air leak in the induction system? It would be nice to know what member micractiv did to solve his P0171 fault code.

I will also post this on the Micra Sports UK site, so apologies to those who read both.

Regards

Microbe (and yes for those that use Renault and Saab forums it's me!)

microbe

there are some threads on the ilexa forum related to your problem iirc
http://www.ilexa.co.uk/forum/index.php/topic,13204.0.html

frank

Thanks for the link Frank. I think the advice that was given is suited for Mikuni TB, but not the later Bosch one.

I'm going to use the car and see if this fault re-appears. If so, I will check to see if there is anywhere that air is getting in to the induction system. If not, then I will either replace the Air Mass sensor (£40, although it is secured with anti tamper screws and my set of same sockets do not fit - must be a strange size) or if I feel flush I will play safe and replace the whole TB, which seems a shame as the it must only be one if the sensors that is broken.

From the UK site the advice is that the earlier TB is not suitable.

I'm not trying to mod this car - it is just a little run around to replace my aging Corsa 1.2 8v which has been a brilliant little bus for the past 3 years. Now just need to get the Micra an MOT.....

For the error code "System too lean..." Proposing this solution :

My investigation with 1.4 2000 -model was started after Engine Light started.

1st it said something like catalytic converter is weak ...

So thought that the 2nd Oxygen sensor might went off and replaced it with the cheapest one paying around 25 EUR + postage.

After that getting just that 701 error code.

Consulting with the friend who recommend to swap the oxygen sensors as there is two : one front of catalytic converter and other after that.

That solved he problem and engine is running without warnign light.