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

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test Q: The Low Oil Pressure Warning Indicator Is Never/Always On (Except Hybrid)

Refer to Wiring Diagram Set 60 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), 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 through circuit CMC24 (GY). When the oil pressure is within normal ranges, 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 off the low oil pressure warning indicator. When the engine oil pressure is low, the engine oil pressure switch opens, sending the reference voltage to the normal voltage in the IC. The IC senses the normal reference voltage and turns the low oil pressure warning indicator on.

This pinpoint test is intended to diagnose the following:

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



PINPOINT TEST Q: THE LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON (EXCEPT HYBRID)

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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Q1 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 Q2.

If the low oil pressure warning indicator is never on, GO to Q6.

No
GO to Q8.

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Q2 CHECK THE ENGINE OIL PRESSURE SWITCH OPERATION


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

Yes
REMOVE the jumper wire. GO to Q3.

No
REMOVE the jumper wire. GO to Q4.

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Q3 CARRY OUT THE ENGINE OIL PRESSURE TEST


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

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

No
Refer to Engine. Testing and Inspection

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Q4 CHECK CIRCUIT CMC24 (GY) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: IC C220.
- Ignition ON.
- Measure the voltage between the IC C220-8, circuit CMC24 (GY), harness side and ground.




- Is any voltage present?

Yes
REPAIR the circuit. TEST the system for normal operation.

No
GO to Q5.

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Q5 CHECK CIRCUIT CMC24 (GY) FOR AN OPEN


- Ignition OFF.
- Measure the resistance between the IC C220-8, 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 Q8.

No
REPAIR the circuit. TEST the system for normal operation.

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Q6 CHECK THE ENGINE OIL PRESSURE SWITCH OPERATION


- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103.
- Ignition ON.
- Monitor the low oil pressure warning indicator with the engine oil pressure switch disconnected.
- Does the low oil pressure warning indicator turn on?

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

No
GO to Q7.

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Q7 CHECK CIRCUIT CMC24 (GY) FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: IC C220.
- Measure the resistance between the IC C220-8, circuit CMC24 (GY), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to Q8.

No
REPAIR the circuit. TEST the system for normal operation.

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Q8 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 determine if 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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