Dear forum,

with my German 2019 C7 Grand Sport (no mods) I mostly drive on the racetrack (as a slightly advanced driver), the rest is on arrivals and departures to the track and for recurring services/maintenance; seldom a drift training session.

At the end of 2022, the check engine light (MKL/CEL) came on during a track day, diagnosis: O2 sensor bank 1, sensor 1 only delivered a voltage value that didn't change (I'm no longer sure whether the MKL/CEL was permanently lit or flashing).

After repairs and no problems in 2023 with approx. 1000 kilometers of race track, the MKL/CEL (steady light) came back the day before yesterday during a track day, diagnosis: O2 sensor bank 1, sensor 1 only delivered a voltage value that did not change.

(By the way: I was still able to drive with the MKL/CEL permanently lit without noticing any problems (I hadn't even noticed it at first); I stopped driving when further errors were reported ("service the rear axle") and the engine no longer worked properly and the MKL/CEL started flashing.)

In terms of laptop diagnostics, apparently identical to the end of 2022;
see also the attached image with the following error codes:
P0030,
P0031,
P0132,
P0135.

Do lambda sensors break down so quickly (I haven't found much about them so far)?
Are there any other possibilities as to what this could be?

A few years ago it was suspected that some batches of O2 sensors might have had a problem (O2 sensor issue reported by Foosh).

Thanks in advance!

 

A flashing MIL along with “Service Rear Axle” is a cat damaging misfire…3 of your 4 DTC’s are O2 Sensor heater circuit malfunctions…are you seeing 450 millivolts (Bias Voltsge) on your scan tool ??…the heater circuit uses 12 volt power and a PWM (Pulse Width Modulated) ground supplied by the ECM…not knowing your electrical skills I’ll stop here…could be wiring or a bad sensor….the P0132 is a B1S1 “high” voltage not associated with the heating circuit.

 

I've but one question... did you use an OEM sensor replacement a year ago? If not, use one this time. I've had problems with other non-OEM "high performance" parts which I ended-up replaced with OEM and problem solved; yes, more than once. All the best.

 

That's all I have from the workshop's scan tool.

Not really much electrical skills on my side ...I have an iCarsoft FD V1.0, but no experience with it and no knowledge what to look for.

The workshop ordered 2 replacement sensors for me, one for immediate replacement before the next track day, and the other because I fear it will happen again too soon; maybe the issue is somewhere else...

 

Thanks! I think so, the part number was 12655677.

Could order it from the US via amazon.de at a really good price (not sure of customs), but it would arrive too late; regular price here in Germany is almost double that with around 125 EUR before taxes.