4D2 ABZ 1996 4.2Q Oxygen sensor

[bloem]

Hello all,

I've been getting multiple misfiring on bank 1 all 4 cylinders. Disconnected the B1 lambda sensor and problem went away. Ordered a replacement oxygen sensor, but problem remained. Verified all wiring to the ECU, and finally swapped B1 and B2 lambda sensors. Problem shifted to bank 2. Here are the part numbers for the sensor:

ETKA: 021 906 265 AK

Bosch: 0 258 003 842 (overall length 750mm)

The one remaining working one on the car is a:

Bosch 0 258 003 454/455 (VAG: 077 906 265 D)

Both the ETKA part number and the old Bosch number have been replaced by the new Bosch number (...842). However the old sensor with cabling is nowhere near as long as the replacement.

The fact that the problem shifted points directly at the sensor itself. At the moment I'm assuming new sensor is faulty from the word go. Awaiting arrival of replacement for the replacement as it were.

Has anybody experienced this before? Am I overlooking something?

Many thanks,

BB

Cross posted from 4D2 ABZ 1996 4.2Q Oxygen sensor - AudiWorld Forums

[graynada8]

If you have moved the sensor and the fault has moved to the other bank that in my opinion it can only be the sensor. Lambda sensor testers are available that would tell you for sure. You can buy one fairly cheaply (about £20 from Draper) or, if you are a dab hand with a soldering iron, I have a design for a self build one on my website that will cost about £5 in components.

[bloem]

Thanks Graham,

I'm also convinced it has to be the sensor. I should be getting a replacement today, so once that's in I'll know more.

BB

[bloem]

The replacement for the replacement sensor works fine...

Once again the wise lesson repeated: never trust a new part.

BB