Pinpoint Test F: Incorrect Oil Pressure Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test F: Incorrect Oil Pressure Gauge Indication
Normal Operation
The Instrument Cluster (IC) is hardwired to the normally open engine oil pressure switch through circuit CMC24 (GY). The IC 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. The IC detects no change in the reference voltage and the oil pressure gauge remains in low oil pressure of the gauge. With the engine running and sufficient oil pressure, the engine oil pressure switch closes, pulling the reference voltage low. The IC then commands the oil pressure gauge to the normal oil pressure range.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Engine oil pressure switch
- Base engine concern
- IC
PINPOINT TEST F: 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.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.
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F1 CARRY OUT THE IC OIL PRESSURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC oil pressure gauge active command (OIL_GAUGE) on and off to sweep the gauge.
- Does the engine oil pressure gauge sweep to the normal range 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 F2.
If the oil pressure gauge always reads low (L) and does not register any oil pressure, GO to F4.
No
GO to F7.
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F2 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.
For diesel engine, REFER to Computers and Control Systems. TEST the system for normal operation
No
GO to F3.
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F3 CHECK CIRCUIT CMC24 (GY) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C220.
- Measure the resistance between the IC C220-22, circuit CMC24 (GY), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to F7.
No
REPAIR the circuit. TEST the system for normal operation.
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F4 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 engine oil pressure gauge.
- Does the engine oil pressure gauge indicate normal oil pressure?
Yes
REMOVE the jumper wire. GO to F6.
No
LEAVE the jumper wire connected. GO to F5.
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F5 CHECK CIRCUIT CMC24 (GY) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect: IC C220.
- With the jumper wire in place, measure the resistance between the IC C220-22, circuit CMC24 (GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
REMOVE the jumper wire. GO to F7.
No
REMOVE the jumper wire. REPAIR the circuit. TEST the system for normal operation.
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F6 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.
For diesel engine, REFER to Computers and Control Systems. TEST the system for normal operation
No
REFER to Engine to continue diagnosis of the engine oil pressure. Testing and Inspection
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F7 CHECK FOR CORRECT IC OPERATION
- Disconnect the IC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC 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. 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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