Pinpoint Test J: The Low Oil Pressure Warning Indicator Is Never/Always On
Instrumentation and Warning Chimes
Pinpoint Tests
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) 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. The IC 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. The IC 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
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. Refer to Battery.
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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_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.
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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. REFER to Engine. TEST the system for normal operation.
No
GO to J3.
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J3 CHECK THE OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C220a.
- Measure the resistance between the IC 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.
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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.
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J5 CHECK THE LOW OIL PRESSURE INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect: IC C220.
- With the jumper wire in place, measure the resistance between the IC 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.
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J6 CHECK THE OIL PRESSURE
- Carry out the engine oil pressure test. Refer to Engine, Component Tests. Oil Pressure Test
- Is the oil pressure within specification?
Yes
INSTALL a new engine oil pressure switch. REFER to Engine.
No
REFER to Engine to continue diagnosis of the engine oil pressure.
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J7 CHECK FOR CORRECT IC OPERATION
- Disconnect the IC connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect 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) Service and Repair. 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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