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

Instrumentation and Warning Chimes

Pinpoint Test

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

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

Normal Operation

The Instrument Cluster (IC) is hardwired directly to the engine oil pressure switch. When the engine is running and normal oil pressure exists, the engine oil pressure switch closes providing a ground to the IC and the low oil pressure warning indicator turns off. When the key is in the RUN position and the engine is off (KOEO) or there is low oil pressure, the engine oil pressure switch opens, removing the ground to the IC and the low oil pressure warning indicator is turned on.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Base engine concern
- Engine oil pressure switch
- IC



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.

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J1 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC low oil pressure warning indicator (OIL_P_LOW) active command. Command the low oil pressure 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 J4.

If the low oil pressure warning indicator is always on, GO to J2.

No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

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J2 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, circuit CMC24 (GY), harness side and ground.




- Ignition ON.
- Does the low oil pressure warning indicator turn off?

Yes
REMOVE the jumper wire. GO to J6.

No
REMOVE the jumper wire. GO to J3.

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J3 CHECK THE OIL PRESSURE INPUT CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: IC C220a.
- Measure the resistance between the IC C220a-7, circuit CMC24 (GY), harness side and the engine oil pressure switch C103, circuit CMC24 (GY), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to J7.

No
REPAIR circuit CMC24 (GY) for an open. TEST the system for normal operation.

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J4 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.
- Is the low oil pressure warning indicator on?

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

No
GO to J5.

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J5 CHECK THE OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: IC C220a.
- Measure the resistance between the IC C220a-7, circuit CMC24 (GY), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to J7.

No
REPAIR circuit CMC24 (GY) for a short to ground. TEST the system for normal operation.

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J6 CARRY OUT THE OIL PRESSURE TEST


- Carry out the oil pressure test. Oil Pressure Test
- Is the oil pressure within specification?

Yes
INSTALL a new EOP switch. REFER to Engine. TEST the system for normal operation.

No
REFER to Engine.

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J7 CHECK FOR CORRECT IC OPERATION


- Disconnect all the IC connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the IC 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. REFER to Instrument Cluster (IC) 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.

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