Engine Oil Pressure Sensor/Switch Diagnosis

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) applies battery voltage through a pull up resistor to the engine oil pressure switch circuit. The PCM monitors the applied voltage on the engine oil pressure switch circuit. If the ignition is turned ON with the engine OFF, or engine oil pressure is below 35 kPa (5 psi), the engine oil pressure switch grounds the PCM voltage input. The PCM sends the engine oil pressure information via Class II serial data to the Instrument Panel (IP) cluster. The IP cluster controls the engine oil pressure indicator.

DIAGNOSTIC AIDS
The low oil pressure message may not appear if other messages are being commanded, such as the rear compartment lid open, driver or passenger doors ajar. Before diagnosing a low oil pressure condition ensure that all doors and compartment lids are completely closed. For diagnosis of the Instrument Cluster, perform A Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Warning Indicators. Testing and Inspection

Inspect for the following conditions:

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection - Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness - Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.