Test D: Incorrect Oil Pressure Gauge Indication

PINPOINT TEST D: INCORRECT OIL PRESSURE GAUGE INDICATION

D1-D4:

D4-D5:

Normal Operation
The engine oil pressure switch is a normally open switch. The instrument cluster provides a reference voltage to the oil pressure switch on circuit 31 (WH/RD). When the oil pressure is within normal ranges, the engine oil pressure switch closes to ground pulling the reference voltage low to the instrument cluster. The instrument cluster, upon receipt of the ground signal, commands the oil pressure gauge to the normal or mid-range position. When the oil pressure is low the engine oil pressure switch opens, removing the ground, and the instrument cluster commands the oil pressure gauge to the L (low) position.

Possible Causes
- Circuit 31 (WH/RD) open or short to ground
- Circuit 1308 (BN/OG) open or short to ground (diesel only)
- Engine oil pressure switch
- Base engine concern
- Instrument cluster