Possible Causes

Circuit (GY) open or short to ground
Oil pressure switch
Base engine concern
Instrument cluster

CAUTION:

Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON - PINPOINT TEST REFERENCE

PINPOINT TEST 3		LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON
STEP	INSPECTION		ACTION
1	CARRY OUT THE INSTRUMENT CLUSTER INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL Key ON. Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command Select the instrument cluster indicator lamp control active command. Select the low oil pressure indicator active command on and off. Observe the low oil pressure warning indicator. Does the low oil pressure warning indicator illuminate when commanded on, and turn off when commanded off?	Yes	If the low oil pressure warning indicator is inoperative, Go to next step. If the low oil pressure warning indicator is always on, go to step 4.
1		No	Go to step 7.
2	CHECK FOR A STUCK OPEN OIL PRESSURE SWITCH Key OFF. Disconnect the oil pressure switch 0922-103. Connect a fused (5A) jumper wire between the oil pressure switch connector 0922-103, circuit (GY) and ground. Key ON engine OFF (KOEO). Is the low oil pressure warning indicator on?	Yes	Install a new oil pressure switch. See OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 2.3L , OIL PRESSURE SENSOR REMOVAL / INSTALLATION - 3.0L , , or OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 4.0L . Test the system for normal operation
2		No	Go to next step.
3	CHECK CIRCUIT (GY) FOR AN OPEN Key OFF. Disconnect instrument cluster 0922-102. Measure the resistance between the instrument cluster connector 0922-102 pin 7, circuit (GY) and the oil pressure switch connector 0922-103, circuit (GY). Is the resistance less than 5 ohms?	Yes	Go to step 7.
3		No	REPAIR the circuit. TEST the system for normal operation.
4	CHECK A FOR STUCK CLOSED OIL PRESSURE SWITCH Key OFF. Disconnect the oil pressure switch 0922-103. Key ON. Observe the low oil pressure warning indicator. Is the low oil pressure warning indicator on?	Yes	Go to next step.
4		No	Install a new oil pressure switch. See OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 2.3L , , OIL PRESSURE SENSOR REMOVAL / INSTALLATION - 3.0L , , or OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 4.0L . Test the system for normal operation
5	CHECK CIRCUIT (GY) FOR A SHORT TO GROUND Key OFF. Disconnect: Instrument cluster 0922-102. Measure the resistance between the instrument cluster 0922-102 pin 7, circuit (GY), harness side and ground. Is the resistance greater than 10,000 ohms?	Yes	Go to next step.
5		No	Repair the circuit. Test the system for normal operation.
6	CARRY OUT THE OIL PRESSURE TEST Carry out the oil pressure test. See ENGINE INSPECTION , . Is the oil pressure within specification?	Yes	Install a new oil pressure switch. See OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 2.3L , , OIL PRESSURE SENSOR REMOVAL / INSTALLATION - 3.0L , , or OIL PRESSURE SENSOR REMOVAL / INSTALLATION -- 4.0L . Test the system for normal operation
6		No	See ENGINE INSPECTION , to continue diagnosis of the engine oil system.
7	CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all the instrument cluster connectors. Check for: corrosion damaged pins pushed-out pins Connect all the instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	Install a new instrument cluster. see INSTRUMENT CLUSTER . Test the system for normal operation.
7		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.