CEL with 2 Fault Codes.

**rayiish** · 09-15-2008 07:30 AM

I recently got a CEL to what I thought was due to my DV giving out. So I just went to Autozone yesterday to get my car scanned for fault codes and surprisingly I received 2.

P0171
Definition: Fuel trim bank one condition.

Explanation: The powertrain control module uses the oxygen sensor to calculate the air/fuek ratio of the engine. The computer has recongnized a rich or lean condition on one engine bank only.

Probable Causes:
1- If bank one and two codes set together suspect fuel pressure or MAF (mass air flow) Sensor
2- Oxygen sensor defective
3- Ignition misfire-repair
4- Fuel injector problem.

P0507
Definition: IAC Circuit Condition or Idle Speed Higher/Lower than expected

Explanation: The ECM has detected that the IAC counts are higher or lower than expected. The engine speed is not in its expected range.

Probable Causes:
1- Vacuum leak on engine
2- Dirty throttle body
3- IAC motor defective
4- Poor eletrical connection to the IAC valve

So the guy behind the counter (highly doubt that has any knowledge in regards of German vehicles) said its my O2 sensor, I need to clean my Air filter, and change ALL my spark plugs. I think the P0507 could be the DV but what is the other fault code about? Could my O2 sensor actually be messed up since I get only "235 miles" on a full tank of gas (have a picture to prove it). Any comments would help, TIA

-Ray

**Sanjman** · 09-15-2008 09:55 AM

sounds like a faulty O2 sensor to me... doesn't the O2 sensor tell the EPC how rich/lean the car is running and adjust it air/fuel ratio? If so, then I could see those fault codes pop up. Strictly my opinion. Also, if you think you know more than the technician behind the counter why the hell are you asking us? lol

**rayiish** · 09-15-2008 09:58 AM

Thats what I'm thinking too because getting "235 miles" on a full tank of gas is pretty god damn ridiculous.

**vtracer20** · 09-15-2008 10:30 AM

^ ouch....how the o2 fixes your prob

**rayiish** · 09-15-2008 01:02 PM

yea cause 13.8 per gallon city is like definitely not what i would except from an A4

**rayiish** · 09-15-2008 04:56 PM

TTT! I need some ideas of what it is. I just bought my DV but if thast not the problem then I might as well bring it to my dealer first to get everything fixed and then install my DV/boost gauge.

**rayiish** · 09-16-2008 08:47 AM

bump!

**elwigglero** · 09-16-2008 09:07 AM

replace your O2 sensor yet?

**rayiish** · 09-16-2008 09:11 AM

Just scheduled an appointment at my local Audi dealership. Next monday morning.

**TCleezy** · 05-07-2009 07:20 PM

what happened with this? I have the exact same 2 codes. The only thing I can think is 5 months ago I put in a carbonio intake, but haven't had any problems until now. I dont have my old airbox and am scared to take it into the dealership cause they will probably just make me pay for it (after a 2 hour drive to get there)