Hey guys,

I bought an A6 Avant 4.2 from 1999 about a week ago. It's in a very good condition for it's milage 135000miles. Ran great when I bought it but after a while it started shuddering when I was driving at 75mph. I immediately stopped along the highway and it started shuddering once again...

First I thought it was something with the tranny, but since it continues when I put it in N or P it shouldn't be the tranny.

This happends once every 4-5times I drive it.

A few days after the first incident the car was hard to start, I have to turn the starter for 3-4 seconds before it starts. When it starts it behavies pretty normal. This happends about every other time I start it.

I got myself a VAG-COM and got two engine fault codes:
17528 - Oxygen (Lambda) Sensor Heating: B2 S1: Open Circuit
P1120 - 35-00 - -
16538 - Oxygen (Lambda) Sensor B2 S1: No Activity
P0154 - 35-00 - -


Would you say this is my problem described?! No other error codes whatsoever.


Thanks,
Tomas

 

Yeah its saying you need a new O2 sensor on the driver's side (bank 2) before the cat converter which reports the air fuel ratio to the ECM which would cause all the problems your experiencing.

Replacing the front O2 sensors on a 4.2L is a biatch though. [:'(]

 

Does it say the O2 sensor needs to be replaced or could the connector be loose or something?

I have a Bentley manual on it's way so I hope the replacement work is doable... I'm planning to change the tranny oil and some other stuff as well.

 

Most O2 sensors only last about 100 thousand miles, even if it were before 100k i would still say its the O2 sensor. Its a fat chance its the wiring, audi factory wiring is top notch.

 

My o2 sensor comes on every time I have major problems or work on something on my car. I dont notice any change in driving but I believe new o2 sensors will waken the car up.

 

Should I replace both at the same time, I have no idea if the other one has been replaced but it would be a shame to replace a perfectly good one since they are not that cheap.

When do Audi replace the fuel filter and spark plugs? Spark plugs every 35-40k miles?!

What weight oil do Audi use in the motor?

 

Yeah, one more thing.

Is there any difference between the ART and ARS engines? I believe the ART is the US model and the ARS is the EU model. Is perhaps that the only difference - where it was sold?!

 

You should replace both the o2 sensors.. If you still have 1 good sensor I would keep it around just incase for the future.

 

I replaced the bad O2 sensor and now it runs perfectly. It took me about 15 minutes so it was a really easy fix!!!

Altough it's still sometimes hard to start... I will replace the spark plugs so hopefully that will take care of the problem.