Pinpoint Test S: The Low Oil Pressure Warning Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test S: 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 engine oil pressure switch is hardwired to the Smart Junction Box (SJB) through circuit CMC24 (GY). When the oil pressure is within normal ranges, the oil pressure switch closes, grounding the signal to the SJB. The SJB then sends a command message to the Instrument Cluster (IC) over the communication network, to turn off the low oil pressure warning indicator. When engine oil pressure is low, the engine oil pressure switch opens, removing the ground to the SJB. The SJB sends a low oil pressure message to the IC over the communication network to illuminate the low oil pressure warning indicator.
- DTC C1284 (Oil Pressure Switch Failure) - an on-demand DTC that sets in the SJB if the SJB detects a short to ground on the oil pressure input circuit CMC24 (GY).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Engine oil pressure switch
- Base engine concern
- SJB
- IC
PINPOINT TEST S: 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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S1 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 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 original symptom is the oil pressure indicator is never on, GO to S2.
If the original symptom is the oil pressure indicator is always on, GO to S4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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S2 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 S3.
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S3 CHECK CIRCUIT CMC24 (GY) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-26, circuit CMC24 (GY), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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S4 MONITOR THE LOW OIL PRESSURE WARNING INDICATOR
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103.
- Ignition ON.
- Connect a fused jumper wire between the engine oil pressure switch C103-1, circuit CMC24 (GY), harness side and ground.
- Does the low oil pressure warning indicator turn off?
Yes
REMOVE the jumper wire. GO to S5.
No
REMOVE the jumper wire. GO to S6.
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S5 CARRY OUT THE ENGINE OIL PRESSURE TEST
- Carry out the engine oil pressure test. Testing and Inspection
- Is the engine oil pressure within specification?
Yes
INSTALL a new engine oil pressure switch. TEST the system for normal operation.
No
REFER to Engine. Testing and Inspection
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S6 CHECK CIRCUIT CMC24 (GY) FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-26, circuit CMC24 (GY), harness side and the engine oil pressure switch C103-1, circuit CMC24 (GY), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to S7.
No
REPAIR the circuit. TEST the system for normal operation.
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S7 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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 SJB. REFER to Body Control Systems. 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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