P0507 Code on 1997 Chevrolet Cavalier 2.2L - Fan-Related Issue and IAC/PCV Replacement Help

Model: 1997 chevrolet cavalier Fault Code: P0507 Posted: 2007-01-06 11:08

I'm experiencing a P0507 diagnostic trouble code on my 1997 Chevrolet Cavalier with a 2.2L engine. After replacing the Idle Air Control (IAC) valve and Positive Crankcase Ventilation (PCV) system, and thoroughly checking for vacuum leaks, the P0507 code persists. A local shop performed a continuous monitoring test and found that the code only appears when the cooling fan activates—specifically under fan operation, not during normal driving conditions or other loads. They recommend replacing the engine control module (ECM) due to potential software glitches. This is the first time I've heard of such behavior, so I'm seeking advice from experienced users. The car is my son's and it needs to pass a vehicle inspection for him to attend school. Any insights into possible causes or troubleshooting steps would be greatly appreciated.