Error Code 0171

[knobby]

Hello there.

3 days ago the engine light came on and when I pulled the code its came up Error 0171, which is Engine Running Too Lean (Bank 0).
Engine was running fine, idling fine, and pulling as normal.
Yesterday engine light disappeared but the error code still persists.
I've reset the ECU twice, yesterday and day before, and I've also cleaned the MAF.....

Any suggestions greatly appreciated

Matthew

[Dandle]

The probable causes for that fault are Intake/exhaust leak, Secondary Air Injection (AIR) system, Mass Air Flow (MAF)/Volumetric Air Flow (VAF) sensor, fuel pressure/pump, injector(s), Heated Oxygen Sensor (HO2S).

[Liberty555]

Knobby

May or may not be related, but I ran some fuel system cleaner through a VW about a year back, really improved things but the engine light kept coming on, then going out after a day or two. It seems they flushed a lot of rubbish out of the system which upset the O2 sensor. After a while it cleaned itself out. I removed the first sensor, cleaned and soaked in Carb cleaner and the problem has not returned.

The error cose I got in that instance was that it was running too rich - just a thought.

[knobby]

Originally Posted by knobby

Hello there.

3 days ago the engine light came on and when I pulled the code its came up Error 0171, which is Engine Running Too Lean (Bank 0).
Engine was running fine, idling fine, and pulling as normal.
Yesterday engine light disappeared but the error code still persists.
I've reset the ECU twice, yesterday and day before, and I've also cleaned the MAF.....

Any suggestions greatly appreciated

Matthew

Forgot to say the car is a 2001 2.0T (chipped)

[pyaap]

Since the car is "chipped", I'd be looking into the MAF sensor and fuel pressure system in the first instance. Just giving the MAF a clean does not mean there isn't a problem with it. In addition, running higher boost puts and extra demand on fuel pressure so you need to be sure the fuel pump and pressure regulator are up to the job. I believe the P0171 would be stored in the ECU, under a manufacturer specific code, as a permanent fault code and hence you may need to get it reset using VADIS/VIDA. Is there a dealer anywhere near you where you can get the codes read / reset? Whereabouts in the country are you?

[knobby]

Originally Posted by pyaap

Since the car is "chipped", I'd be looking into the MAF sensor and fuel pressure system in the first instance. Just giving the MAF a clean does not mean there isn't a problem with it. In addition, running higher boost puts and extra demand on fuel pressure so you need to be sure the fuel pump and pressure regulator are up to the job. I believe the P0171 would be stored in the ECU, under a manufacturer specific code, as a permanent fault code and hence you may need to get it reset using VADIS/VIDA. Is there a dealer anywhere near you where you can get the codes read / reset? Whereabouts in the country are you?

Cheers Pyaap.

I had the car chipped 'bout 3months ago and only now the error popped up...!!
I've got the car bookd into a specialist on Friday (Bridgend S.Wales) so I tell them to plug it into VADIS?

Thanks again

Mat

[pyaap]

Who did the remap and did they do any checks to see what the air-fuel ratio was?

In the first instance, get the ECU read for any fault codes there may be. If its suspected to be a fuel pressure regulator issue, there is a bleed nipple on the fuel rail with a Schrader valve on it - just hook that up to a pressure gauge and you should see 3bar with the ignition on and around 2.5bar with the engine running. The problem with this to see how the fuel pump is coping, you need to put the engine under load to see how the fuel pressure varies, so that will be very tricky - probably best done on a rolling road IMO.

If you're heading across the Severn bridge and would like me to have a go at "reading" the ECU for fault codes, let me know and maybe we can meet up at The Mall at Cribbs Causeway.

[knobby]

Cheers, thanks for your help Pyaap.

I'll see what happens Friday and get back to you. I would happily drive to Cribbs (wife will love it too...) and thanks for the offer.

I'll mention to the garage your suggestions and see what happens.

What I couldn't understand woz why it has the problem only manifested itself 3 months after the chipping? (Upsolute BTW)....

Thanks
Mat

[pyaap]

Originally Posted by knobby

What I couldn't understand woz why it has the problem only manifested itself 3 months after the chipping? (Upsolute BTW)....

The reason I asked is higher boost does place additional demands on the fuel system (especially pump) and T4 fuel systems are quite weird, so any issues with it will very quickly flag up problems. I would definitely look to the MAF and fuel system in the first instance.