Hola AF gang! I have a '01 A4 Quattro 2.8l and it's sick...

It started last week when I was driving home from work. Felt like the tranny was engaging and disengaging (back and forth a few times) then the engine died and I rolled to a stop... CEL came on and so I plugged my VAG-COM in (yep, I carry it in the glove box) and it threw me the following codes.

16534 - Oxygen (Lambda) Sensor B2 S1: Malfunction in Circuit
P0150 - 35-10 - - - Intermittent

Here is a read on the B2S1 before I replaced it:

TID 01 - Rich to lean sensor threshold voltage Test:0.435 V
TID 02 - Lean to rich sensor threshold voltage Test:0.435 V
TID 03 - Low sensor voltage for switch time calculation N/A
TID 04 - High sensor voltage for switch time calculation N/A
TID 05 - Rich to lean sensor switch time N/A
TID 06 - Lean to rich sensor switch time N/A
TID 07 - Minimum sensor voltage for test cycle Test:0.030 V - Min:0.005 V - Max:0.385 V
TID 08 - Maximum sensor voltage for test cycle Test:1.080 V - Min:0.480 V - Max:1.005 V
TID 09 - Time between sensor transitions Test:0.160 s - Min:0.040 s - Max:1.000 s
TID 10 - Sensor period N/A

So as you can see, the Max sensor voltage was out of parameter, so I figured this is the problem and off to the auto parts store I went. After 140.00 for a new o2 sensor and fancy little o2 sensor wrench I headed for the shop. A quick 10 minutes later and I had the sensor replaced. Put the car back together, and cleared the codes before heading out for a test drive.

Not 20 blocks into the test drive, it started doing the same thing again... No CEL, just engage / disengage and then the engine dies. So I limped it back home, and tried to pull codes... Nada, zip, zilch. The ECU thinks everything is great. No codes.

I did a scan of all the o2 sensors and this is what I came up with now...


B1S1

TID 01 - Rich to lean sensor threshold voltage Test:0.435 V
TID 02 - Lean to rich sensor threshold voltage Test:0.435 V
TID 03 - Low sensor voltage for switch time calculation N/A
TID 04 - High sensor voltage for switch time calculation N/A
TID 05 - Rich to lean sensor switch time N/A
TID 06 - Lean to rich sensor switch time N/A
TID 07 - Minimum sensor voltage for test cycle Test:0.195 V - Min:0.005 V - Max:0.385 V
TID 08 - Maximum sensor voltage for test cycle Test:0.675 V - Min:0.480 V - Max:1.005 V
TID 09 - Time between sensor transitions Test:0.000 s - Min:0.040 s - Max:1.000 s
TID 10 - Sensor period N/A

B1S2

TID 01 - Rich to lean sensor threshold voltage Test:0.575 V
TID 02 - Lean to rich sensor threshold voltage Test:0.575 V
TID 03 - Low sensor voltage for switch time calculation N/A
TID 04 - High sensor voltage for switch time calculation N/A
TID 05 - Rich to lean sensor switch time N/A
TID 06 - Lean to rich sensor switch time N/A
TID 07 - Minimum sensor voltage for test cycle Test:0.310 V - Min:0.000 V - Max:0.575 V
TID 08 - Maximum sensor voltage for test cycle Test:0.480 V - Min:0.575 V - Max:1.005 V
TID 09 - Time between sensor transitions N/A
TID 10 - Sensor period N/A

B2S1

TID 01 - Rich to lean sensor threshold voltage Test:0.435 V
TID 02 - Lean to rich sensor threshold voltage Test:0.435 V
TID 03 - Low sensor voltage for switch time calculation N/A
TID 04 - High sensor voltage for switch time calculation N/A
TID 05 - Rich to lean sensor switch time N/A
TID 06 - Lean to rich sensor switch time N/A
TID 07 - Minimum sensor voltage for test cycle Test:0.195 V - Min:0.005 V - Max:0.385 V
TID 08 - Maximum sensor voltage for test cycle Test:0.675 V - Min:0.480 V - Max:1.005 V
TID 09 - Time between sensor transitions Test:0.000 s - Min:0.040 s - Max:1.000 s
TID 10 - Sensor period N/A

B2S2

TID 01 - Rich to lean sensor threshold voltage Test:0.575 V
TID 02 - Lean to rich sensor threshold voltage Test:0.575 V
TID 03 - Low sensor voltage for switch time calculation N/A
TID 04 - High sensor voltage for switch time calculation N/A
TID 05 - Rich to lean sensor switch time N/A
TID 06 - Lean to rich sensor switch time N/A
TID 07 - Minimum sensor voltage for test cycle Test:0.410 V - Min:0.000 V - Max:0.575 V
TID 08 - Maximum sensor voltage for test cycle Test:0.805 V - Min:0.575 V - Max:1.005 V
TID 09 - Time between sensor transitions N/A
TID 10 - Sensor period N/A


Now it says time between sensor transition is zero?!?! WTF?!?

Any ideas?

also have .csv files of o2 sensor logging if anyone wants to take a peek.