Pinpoint Test J: The Low Oil Pressure Warning Indicator Is Never/Always On

Instrumentation and Warning Chimes

Pinpoint Test J: The Low Oil Pressure Warning Indicator Is Never/Always On

Refer to Wiring Diagrams Set 60, Instrument Cluster for schematic and connector information. Electrical Diagrams

Normal Operation

The Instrument Cluster (IC) provides a reference voltage to the engine oil pressure switch. When the engine oil pressure is low, the engine oil pressure switch closes to ground, pulling the reference voltage low in the IC (Instrument Cluster). The IC (Instrument Cluster) senses the low reference voltage and turns on the low oil pressure warning indicator. When the engine oil pressure is within normal ranges, the engine oil pressure switch opens and the reference voltage remains high in the IC (Instrument Cluster). The IC (Instrument Cluster) senses the reference voltage high and turns off the low oil pressure warning indicator.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Engine oil pressure switch

- Base engine oil pressure concern

- IC (Instrument Cluster)

PINPOINT TEST J : THE LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON

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

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

J1 CARRY OUT THE IC (Instrument Cluster) INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) DataLogger.

- Select the IC (Instrument Cluster) low oil pressure warning indicator (OIL_P_L) 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 always on, GO to J2.

If the low oil pressure warning indicator is never on, GO to J4.

No
GO to J7.

J2 CHECK FOR A STUCK CLOSED ENGINE OIL PRESSURE SWITCH

- Ignition OFF.

- Disconnect: Engine Oil Pressure Switch C103.

- Ignition ON.

- Observe the low oil pressure warning indicator.

Does the low oil pressure warning indicator turn on?

Yes
INSTALL a new engine oil pressure switch. TEST the system for normal operation.

No
GO to J3.

J3 CHECK THE OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Disconnect: IC (Instrument Cluster) C220A.

- Measure the resistance between the IC (Instrument Cluster) C220A-26, circuit 31S-GC21 (BK/GN), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to J7.

No
REPAIR circuit 31S-GC21 (BK/GN) for a short to ground. TEST the system for normal operation.

J4 CHECK FOR A STUCK OPEN ENGINE OIL PRESSURE SWITCH

- Ignition OFF.

- Disconnect: Engine Oil Pressure Switch C103.

- Connect a fused jumper wire between the engine oil pressure switch, C103-1, circuit CMC-24 (GY), harness side and ground.





- Ignition ON.

- Observe the low oil pressure warning indicator.

Does the low oil pressure warning indicator turn off?

Yes
REMOVE the jumper wire. GO to J6.

No
LEAVE the jumper wire connected. GO to J5.

J5 CHECK THE LOW OIL PRESSURE INPUT CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Disconnect: IC (Instrument Cluster) C220.

- With the jumper wire in place, measure the resistance between the IC (Instrument Cluster) C220A-26, circuit 31S-GC21 (BK/GN), harness side and ground.





Is the resistance less than 5 ohms?

Yes
REMOVE the jumper wire. GO to J7.

No
REMOVE the jumper wire. REPAIR circuit 31S-GC21 (BK/GN) for an open. TEST the system for normal operation.

J6 CHECK THE OIL PRESSURE

- Carry out the engine oil pressure test. Refer to - Component Tests. Oil Pressure Test

Is the oil pressure within specification?

Yes
INSTALL a new engine oil pressure switch.

No
REFER to Engine to continue diagnosis of the engine oil pressure.

J7 CHECK FOR CORRECT IC (Instrument Cluster) OPERATION

- Disconnect the IC (Instrument Cluster) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect the IC (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 IC (Instrument Cluster). REFER to Instrument Cluster (IC) . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.