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

Instrumentation, Message Center and Warning Chimes

Pinpoint Test R: The Low Oil Pressure Warning Indicator Is Never/Always On (Non-Hybrid)

Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

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

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Engine oil pressure switch

- Base engine oil pressure concern

- IPC (Instrument Panel Cluster)

PINPOINT TEST R : THE LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON (NON-HYBRID)

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.

R1 CARRY OUT THE IPC (Instrument Panel Cluster) INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

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

- Select the IPC (Instrument Panel Cluster) low oil pressure warning indicator (OIL_P_LOW) active command. Command the low oil pressure warning indicator on and off while observing 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 original symptom is the low oil pressure warning indicator is always on, GO to R4.

If the original symptom is the low oil pressure warning indicator is never on, GO to R2.

No
GO to R7.

R2 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 (EOP) switch. TEST the system for normal operation.

No
GO to R3.

R3 CHECK OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Disconnect: IPC (Instrument Panel Cluster) C220.

- Measure the resistance between the IPC (Instrument Panel Cluster) C220-6, circuit CMC24 (GY), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to R7.

No
REPAIR the circuit. TEST the system for normal operation.

R4 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 CMC24 (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 R6.

No
LEAVE the jumper wire connected. GO to R5.

R5 CHECK OIL PRESSURE INPUT CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Disconnect: IPC (Instrument Panel Cluster) C220.

- With the jumper wire in place, measure the resistance between the IPC (Instrument Panel Cluster) C220-6, circuit CMC24 (GY), harness side and ground.





Is the resistance less than 5 ohms?

Yes
REMOVE the jumper wire. GO to R7.

No
REMOVE the jumper wire. REPAIR the circuit. TEST the system for normal operation.

R6 CHECK THE OIL PRESSURE

- Carry out the oil pressure test. Oil Pressure Test

Is the oil pressure within specification?

Yes
INSTALL a new Engine Oil Pressure (EOP) switch. TEST the system for normal operation.

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

R7 CHECK FOR CORRECT IPC (Instrument Panel Cluster) OPERATION

- Disconnect the IPC (Instrument Panel Cluster) connector.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect the IPC (Instrument Panel Cluster) connector and make sure it seats correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . 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.