[MR11]

I recently had my first track day at summit point WV in a 2018 M2 LCI. Normally I run bootmod3 stage 2 93 octane tune but decided to run the stage 2 91 to be on the safe side. I put in about 1.5-2 gallons of E85 and the rest 93. The car ran great but after pulling into the lot and shutting it off for a cool down I noticed a CEL on start up. Reading the codes all come up related to O2 sensors and possibly integrated supply module? [Screenshot attached] ignore the exhaust flap code. I've ordered both pre/post cat sensors and have the ISM pulled out. Currently have the Wagner catless downpipe which is known for having a bad secondary O2 sensor placement which keeps the wire under constant stress. Not sure if anyone has had the same/similar codes but any input/advice would be greatly appreciated!

12B102
Heating lambda probe 1 bank 1 activation: short circuit to ground

12B302
Lambda probe 2 heater Bank1, activation: Short circuit to ground

1B5202
Terminal 15N_ 1: no voltage

[MR11]

Bump.

I replaced both pre-cat and post-cat O2 sensors but still getting the same error. Going to replace the integrated supply module next part number 12-63-7-591-534 / 12-63-8-645-514.

[ThreeStripes]

Were you logging to look at lambda or any other values while out there?

Seems like you’re in the right track regardless. Good luck with it.

[MR11]

Originally Posted by ThreeStripes

Were you logging to look at lambda or any other values while out there?

Seems like you’re in the right track regardless. Good luck with it.

Thanks!

Unfortunately not, I only had the OBD2 to usb-c cable on me and didn't log. The car seems to run fine I did a few pulls after and didn't notice anything odd. On cold start ups I do get a slighty rough idle initially but then back to normal after a few seconds (likely because of 1-2 gallons of E85). AFR is pretty consistent 14.6-14.7 at idle. I'm picking up the part today and will report back. Really hope this fixes it otherwise will probably start looking into possibly break in wires or blown fuse or even the power distributor in the trunk near the battery.

Few things I noticed while taking things out. Secondary O2 sensor had major tension on it to the point where it unseated the plug sensor from the clip that sits on the valve cover near the coil packs. I ended up extending the new secondary O2 sensor. Also noticed a tiny bit of brake fluid that spilled on the integrated supply module but I really don't think it was enough to damage anything but we shall see.

[MR11]

Just an update, installed the new integrated supply module which looked a little different than the previous one and was missing the cap for the power source but everything fits fine. Started it up and check engine light was still there along with same codes. Deleted the codes and they haven't came back yet as opposed to before it would come back upon first start up and the codes were also still there.

So I guess the ISM was the issue (for now). Will update if anything changes.

[ThreeStripes]

Originally Posted by MR11

Just an update, installed the new integrated supply module which looked a little different than the previous one and was missing the cap for the power source but everything fits fine. Started it up and check engine light was still there along with same codes. Deleted the codes and they haven't came back yet as opposed to before it would come back upon first start up and the codes were also still there.

So I guess the ISM was the issue (for now). Will update if anything changes.

Excellent. Let us know if it holds. Careful running the E85 long term. Don’t leave it in the tank long and watch the injectors.

I’d also want to lay eyes on some logs when you’re running ~E20 like that to confirm your HPFP and lamda is OK. Flying blind never advisable.