Test C: Incorrect Oil Pressure Gauge Indication

PINPOINT TEST C: INCORRECT OIL PRESSURE GAUGE INDICATION

C1-C4:

C4-C6:

C6-C8:

Normal Operation
The instrument cluster is hardwired to the normally open engine oil pressure switch through circuit CMC24 (GY). The instrument cluster provides a reference voltage to the engine oil pressure switch when the ignition key is in the RUN position. When there is low or no oil pressure, the engine oil pressure switch remains open. The instrument cluster detects no change in the reference voltage and the oil pressure gauge remains in low oil pressure of the gauge. When the engine is running with sufficient oil pressure the engine oil pressure switch closes, providing a ground, which pulls the reference voltage from the instrument cluster low, the instrument cluster commands the oil pressure gauge to the normal oil pressure area of the gauge.

Possible Causes
- Circuit CMC24 (GY) open, short to ground or voltage
- Engine oil pressure switch
- Base engine concern
- Instrument cluster