Diagnostic Aids

WARNING: This page is about a different car, the 2002 Saturn LW200, 2002 Saturn L200, and 2002 Saturn L100. However, it is still accessible from the selected car via links, so may be relevant.

DTC can set due to:

Intermittent open anywhere in CKP ref. circuits. This will cause tachometer to drop out and most likely stall or disrupt engine operation.
Intermittent short to voltage anywhere in CKP ref. circuit. This will cause tachometer to drop out and may momentarily disrupt engine operation.
Electromagnetic Interference (EMI) caused by high current carrying wiring routed near CKP sensor wiring. EMI can alter amplitude and/or frequency or CKP signal and create invalid CKP pulses.

To locate an intermittent problem, use scan tool to monitor CMP RESYNC COUNTER. If the counter starts counting up, crankshaft pulses are being interrupted, as the PCM has to resync the camshaft position.

DTC may set as a result of an intermittent open or short to ground in CKP ref. circuit.

An open/short to ground in Red/Black wire between PCM and EI module will not affect engine operation or set DTC.