Hey everyone,

I have an 05 evo 8 MR and my car is catless. Ive been using tephramodv7's o2 sim to bypass the CEL and it has been working for a long time. However, after getting the car re-tuned, the car has gotten a CEL, P0136 , which is the rear O2 sensor circuit malfunction. I went back into Ecuflash and saw the rear o2 sim was still turned on and no matter what I do, the CEL always comes back. So I was wondering if the rear O2 sensor went bad during the retune, which is causing the CEL, or if the tuner switched other settings that could be affecting the O2 sim?
Any help is appreciated, thanks!

 

You should have a section in your Tephra Mod Options called Enable Rear O2 Simulator. Make sure it is set to 1.

 

Yep, ive had that turned to 1 yet it still gives me a CEL

 

1. Are you sure the rear O2 sim is working?
2. Is your rear NB still plugged in or are you using the input for WBO2?
3. What value do you have in MUT12?

Log front and rear NB voltages and compare to diagnose if the rear sim patch is working The front voltage should vary up and down while rear remains near constant.
If you can't figure it out you can always turn off P0132 (front) and P0136 (rear) codes in FCA bit 3. The downside is that you won't know if your front NB has failed.

 

Alright I think I got it - I checked the connection on the rear NB and for some reason, the plug was loose? I pushed it back in, reset the CEL, and so far no issues. Not sure how it got loose, but it seems to be working now! Thanks!

 

Glad you fixed it! Thanks for posting your resolution.