Code 538: System Failed To Recognize WOT Test

WARNING: This page is about a different car, the 1995 Ford Aerostar. However, it is still accessible from the selected car via links, so may be relevant.

Repeat KOER SELF-TEST as follows:

Activate SELF-TEST.
Start engine.
Observe ID Code start of test.
Observe Dynamic Response Code 1 (Code 0 with Star tester).
Perform brief WOT.
Testing is complete; Diagnostic Test Code (DTC) output begins.

Ensure vehicle speed reached 2000 RPM during WOT. If Code 538 is present, replace PCM. If Code 538 is not present, vehicle has passed dynamic response test. Service other codes if necessary.