New Audi S4 (54) Owner needs advice!

[lvs409]

I need some help with faults. The car goes like a dream but has fault codes. I went to a garage who said a missfire was detected then reset the unit. It has since returned with a new code pointing to a "bank1 sensor 2 reading rich". Does this mean the sensor is faulty or that the sensor has picked up a fault elsewhere?

Audi charge £90 for checking each time. I'd prefer to spend the money replacing fault! Would appreciate advice. Anyone else experienced this?

 

[white.akita]

i cant help much but it may be of interest to you that there are fault code readers/erasers for sale on ebay for £25, i have one and it seems to work excellent and has saved me alot of money.

 

[ScottyP45]

sounds like the O2 (lambda) sensor on the cat, you should see if you can find a low cost replacement and just swap it, there are 2, one before the cat and one after, dunno which are which but could likely find out mate.

Its a screw in job with 2 wires and really not hard to change if it is faulty, it is the actual sensor so if its bad you need to swap it, or get an emissions test done at a MOT station, that will tell you if the engine is actually running rich or if the sensor is lying cause its faulty, it cant be open circuit or have a broken wire as the message is different like "implausible or no signal" etc etc.

(It measures the oxygen content of the exhaust gases, then after the cat treats them, the second sensor reads the result to see how good the cat is working.)

 

[Tendaimwari]

They are a pain to change. The sensor cable(s) for the main cat sensor(s) is attached to the top of the gearbox. Therefore, it has to be lowered in order to uncouple the wires. The pre-cats are a bit easier to change and can be reached from the engine bay. the correct tool is needed otherwise the cable will become twisted and this makes removing/installation harder.

The quickest and easiest way to change the main cat sensor(s) is to cut the wires, reconnect using electrical connectors and then use heat shrink. Do one wire at a time.