po171 fault code

[audijames]

Hi all i am sure u have all been asked this befor my engine man light comes on every so often the code is po171 say bank1 too lean my car runs and drives fine never skips a beat still goes well could any one help please

 

[marktdisport]

Faulty lambda maybe m8....

 

[audijames]

Was thinking that but if it was that would it be running so well still

 

[marktdisport]

I have known them to give a fault code and light without giving running issues

 

[tom2]

It was an air leak that caused that code on mine, diverter valve was split.

 

[audijames]

As in waste gate i have a forge one that recirculates and atmostheric but had that on nearly a year and its been fine since lol i see alot of pep say about these small plastic valves in the engine bay is there one that plays up more than others as there is about 5in there lol

 

[tom2]

tbh mate i think an air leak anywhere could cause that code as the ratio of fuel to air would not be right, the car can alter the fuel trim on its own but only slightly. It may be that if it is an air leak its is small enough for the car to compensate for but could still trigger the warrning light, is fuel consumption normal? I took mine into audi as it was running like s***, thought at first it was a coil pack. Anyways, to find the leak the guy at audi sprayed 'easy start' on the air pipes/valves etc and when it hit the leak the engine revs picked slightly.

 

[audijames]

Ok will give the easy start a good to look for the leak lol this could be fun lol

 

[hades-]

why dont you have a search 1st

Special Notes [h=2]16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean[/h][h=4]Possible Causes[/h] Mass Air Flow Sensor (G70) defective Intake System Leak(s) [h=4]Possible Solutions[/h] Check Mass Air Flow Sensor (G70) Check Fuel Pressure Regulation Check Fuel Pump Check Injectors Check Intake System for Leaks Check Exhaust System for Leaks Check Secondary Air System for Leaks Check Vacuum Pipes for Leaks [h=4]Special Notes[/h] Fuel Trim Info Retrieved from "16555/P0171/000369 - Ross-Tech Wiki" Category: Fault Codes

[h=5]Categories[/h] Main Page Diagnostic Procedures Common Procedures Fault Codes Retrofitting Immobilizer [h=5]Meta[/h] Log in

 

[audijames]

was going todo it today but yet again its raining thanks for your helps

 

[lemansalot]

I have the same problem on a B6 2.4 , with the same code. I have had fixed a leaky pipe or two and it still does it.

If I clear the codes the engine runs awful on idle for a few miles, then is fine again. Then the codes come in and 100 miles later I get the engine light with P0171 and P0174
Does the engine default to a setting if the mass air flow sensor is duff ?

My helpful audi guy thinks its a breather down in the engine that may be leaking air but looks like a big job...

 

[Ovid]

A scan and diagnostic with vagcom (vcds) will show if its maf.