Engine Oil Pressure Gage

The instrument panel cluster (IPC) displays the engine oil pressure as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 psi (0 kPa) or below if:

• The PCM detects a malfunction in the engine oil pressure sensor circuit.
• The IPC detects a loss of class 2 communications with the PCM.

For the 4.2L LL8, the PCM uses an engine oil switch that is open when the oil pressure is normal and closed when the oil pressure is low. At normal pressure, the engine oil pressure gage will display 275 kPa (40 psi). At low pressure, the gage will go to 0 kPa and the low pressure warning will be displayed in the driver information center (DIC). At high pressure, the gage will display 551 kPa (80 psi). Any values between these three values are calculated values determined by the PCM.