Normal Operation

The instrument cluster is hardwired directly to the oil pressure switch through circuit (GY). The oil pressure switch is a normally open switch. When the engine is running and normal oil pressure exists, the oil pressure switch closes providing a ground to the instrument cluster turning the low oil pressure warning indicator off. When the key is in the RUN position and the engine is off (KOEO) or there is low oil pressure, the oil pressure switch opens, removing the ground to the instrument cluster and illuminating the low oil pressure warning indicator.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connections
Oil pressure switch
Base engine concern
Instrument cluster

CAUTION:

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

LOW OIL PRESSURE WARNING INDICATOR PINPOINT TEST 3

PINPOINT TEST 3		THE 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 in ON position. Enter the following diagnostic mode on the scan tool: Instrument Cluster Data Logger Select the instrument cluster low oil pressure warning indicator (OIL_P_LOW) active command. Command the low oil pressure warning indicator 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 step 4. If the low oil pressure warning indicator is always on, go to next step.
1		No	Go to step 7.
2	CHECK FOR A STUCK OPEN OIL PRESSURE SWITCH Key in OFF position. Disconnect: Oil Pressure Switch connector 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). Does the low oil pressure warning indicator turn off?	Yes	REMOVE the jumper wire. Go to step 6.
2		No	REMOVE the jumper wire. Go to next step.
3	CHECK CIRCUIT (GY) FOR AN OPEN Key in OFF position. Disconnect: Instrument Cluster connector 0922-102. Measure the resistance between the instrument cluster connector 0922-102 pin 7, circuit (GY) harness side and the oil pressure switch connector 0922-103, circuit (GY) harness side. 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 in OFF position. Disconnect: Oil Pressure Switch connector 0922-103. Key in ON position. Observe the low oil pressure warning indicator. Is the low oil pressure warning indicator on?	Yes	INSTALL a new oil pressure switch. See Oil Pressure Sensor Removal / Installation -- 2.3L or Oil Pressure Sensor Removal / Installation -- 4.0L . TEST the system for normal operation
4		No	Go to next step.
5	CHECK CIRCUIT (GY) FOR A SHORT TO GROUND Key in OFF position. Disconnect: Instrument Cluster connector 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 step 7.
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 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.