Pinpoint Test D: Incorrect Oil Pressure Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test D: Incorrect Oil Pressure Gauge Indication
Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information Electrical Diagrams.
Normal Operation
The Instrument Cluster (IC) is hardwired directly to the engine oil pressure switch through the engine oil pressure input circuit. The IC (Instrument Cluster) provides a reference voltage to the engine oil pressure switch when the ignition key is in the RUN position. When there is low or no oil pressure, the engine oil pressure switch remains open, keeping the reference voltage high. The IC (Instrument Cluster) detects no change in the reference voltage and the oil pressure gauge remains in the low oil pressure area of the gauge. When the engine is running with sufficient oil pressure, the engine oil pressure switch closes, providing a ground, which pulls the reference voltage from the IC (Instrument Cluster) low, the IC (Instrument Cluster) commands the oil pressure gauge to the normal oil pressure area of the gauge.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Engine oil pressure switch
- Base engine concern
- IC (Instrument Cluster)
PINPOINT TEST D : INCORRECT OIL PRESSURE GAUGE INDICATION
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
D1 CARRY OUT THE IC (Instrument Cluster) OIL PRESSURE GAUGE 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) oil pressure gauge (OIL_POS) active command on and off to sweep the gauge.
Does the engine oil pressure gauge sweep to high (H) when commanded on and return to low (L) when commanded off?
Yes
If the oil pressure gauge always reads in the normal range, GO to D2.
If the oil pressure gauge always reads low (L) and does not register any oil pressure, GO to D4.
No
GO to D7.
D2 CHECK FOR A STUCK CLOSED ENGINE OIL PRESSURE SWITCH
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103.
- Ignition ON.
- Observe the engine oil pressure gauge.
Does the engine oil pressure gauge indicate low (L) oil pressure?
Yes
INSTALL a new Engine Oil Pressure (EOP) switch. TEST the system for normal operation.
No
GO to D3.
D3 CHECK THE OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC (Instrument Cluster) C220.
- Measure the resistance between the IC (Instrument Cluster) C220-18, circuit CMC24 (GY), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to D7.
No
REPAIR circuit CMC24 (GY) for a short to ground. TEST the system for normal operation.
D4 CHECK FOR A STUCK OPEN ENGINE OIL PRESSURE SWITCH
NOTE: If the fused jumper wire fails, refer to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
- 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 engine oil pressure gauge.
Does the engine oil pressure gauge indicate normal oil pressure?
Yes
REMOVE the jumper wire. GO to D6.
No
REMOVE the jumper wire. GO to D5.
D5 CHECK THE ENGINE OIL PRESSURE INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the IC (Instrument Cluster) C220-18, 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 D7.
No
REPAIR circuit CMC24 (GY) for an open. TEST the system for normal operation.
D6 CHECK THE OIL PRESSURE
- Carry out the engine 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 engine oil pressure.
D7 CHECK FOR CORRECT IC (Instrument Cluster) OPERATION
- Disconnect the IC (Instrument Cluster) connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC (Instrument 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 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. TEST the system for normal operation.