Ha yes, the old monitor reset, this can be difficult, please go over this guide to see if this helps.
https://2carpros.com/articles/how-to-reset-an-engine-computer-monitor-program/
The vehicle uses two PCM connectors:
- C1 (D3838A): Black
- C2 (D3838B): Brown
The O2 sensor signal and heater circuits we're interested in are located in connector C2.
PCM C2 oxygen sensor pin listing
Pin Circuit Wire color Function
18 K904 DB/DG Downstream O2 return
19 K902 BR/DG Upstream O2 return
24 K99 BR/YL O2 1/1 heater control
41 K43 DB/LG O2 2/1 signal
42 K243 BR O2 2/2 signal
43 K141 DB/YL O2 1/2 signal
44 K41 DB/LB O2 1/1 signal
48 K299 BR O2 1/2 heater control supply
72 K199 BR/VT O2 2/1 heater control
96 K399 BR/GY O2 2/2 heater control
If all four heaters respond correctly to scan tool commands, we should also investigate why the PCM isn't completing the readiness tests. That may be a monitor-enable condition rather than a failed circuit. I have seen a bad PCM cause this issue, but go over the guide to make sure it is not a procedural error.
Oct 29, 2026 at 8:31 AM