Hello - I am both new to the forum and new to Audi A4 ownership. All I've ever driven before this magnificent piece of machinery is domestic trucks. I can't even describe how impressed I am with my car!

It is a 1998 A4 1.8T Quattro 5-speed


Here's my problem:
Over the past two days, I've been noticing a marginally strong smell of gasoline inside the vehicle after the car comes up to operating temperature. At first I thought it was the vehicles around me, but this evening I went out on the town to celebrate Election Day and noticed the fuel smell very distinctly while there were no cars around. Two days before this my check engine light came on - I put a simple OBD2 reader on it and the codes it kicked out were "Evaporative Emissions Control System Leak" (Gas cap code), and "Oxygen Sensor Malfunction High Voltage Bank 1 Sensor 1".

My questions are:
Would the O2 sensor being dead make the car run too rich, and therefore cause a smell of fuel in the passenger compartment (it is reminiscent of having gasoline on your hands after pumping gasoline)?

Is the Evaporative Emissions Control System malfunction code not a "Gas Cap" code? Could this system be releasing enough gasoline fumes due to some malfunction to cause me to smell a strong odor of gasoline?

Any information would be fantastic.

Thank you, and I appreciate any and all support. Despite this small problem, I could not be happier with my Audi A4 purchase.

 

Look for the leak.

 

Pull up the back seat cushion and look for leaks around the pump or broken plastic lines. Usually on an A4, if you can smell gas in the car, it's coming from the area of the pump.

NOTE: DO NOT REMOVE PUMP UNLESS TANK IS BELOW 1/4!

As for the O2 sensor code, what is the P or P0 number?

 

what? you dont like being wrist deep in 10 gallons of raw gasoline? im goin to go have a cigarette....

 

Codes are:
P0132: Oxygen Sensor No Output Bank 1 Sensor 1
P0441: Evaporative Emissions Control System Incorrect Purge Flow

I shut the codes off again this morning and so far (I put 60 miles on the car just testing her out), the CEL hasn't come back on & I haven't smelled fuel yet.

 

Aha... there's some mis-interpretation of these DTCs here. Knowing what the DTC actually is brings a lot more info to the table.

P0132: O2 sensor circuit high voltage, Bank 1, Sensor 1. High voltage in an O2 sensor tells the ECM that there is a low concentration of oxygen in the exhaust stream. It's an indication the engine is running rich, not necessarily that the O2 sensor is bad. MAF readings and fuel trim readings can help you pinpoint the issue.

P0441: Evap. emission control system incorrect purge flow. This is not a "gas cap" code. It's not telling you there is a leak, it's telling you there is an incorrect flow when attempting to purge the gas fumes into the engine. It's often chalked up to a bad N80 valve (evap purge valve).

If the N80 is stuck wide open, you -might- get the smell of gasoline on occasion. More likely, you will have high voltage in your O2 sensor readings and the car will sense a false rich condition as there is a higher content of HCs than O2 in the exhaust and the ratio is off.

So... my suggestion is that repairing the evap purge issue (knowing Audi/VW, it likely the N80 valve) may result in simultaneously fixing the O2 sensor code.




P.S.: Erasing the codes is fine for now, but the ECM has to see certain conditions to purge the evap into the intake (usually coasting off a highway). When it fails 3 times again under the same conditions, it will trip the MIL again.

 

OK thanks. Yeah I guess our code-reader book is wrong at my work; which doesn't surprise me, the darn code reader looks like we bought it from a dollar store. After another 160-some-odd miles of driving it hasn't come back on again, I haven't smelled any fuel, and my mileage is back up to 31 MPG. When the light was on I was getting around 24.