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

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

O1 CARRY OUT THE INSTRUMENT CLUSTER INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE DIAGNOSTIC TOOL
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command.
- Select the instrument cluster indicator lamp control active command. Trigger the low oil pressure warning indicator active command on and off. Observe the low oil pressure warning indicator.
- Does the low oil pressure warning indicator illuminate when triggered on, and turn off when triggered off?
Yes : GO to O2.

No : GO to O7.
O2 MONITOR THE LOW OIL PRESSURE WARNING INDICATOR
- Key in OFF position.
- Disconnect: Oil Pressure Switch C103.
- Key in ON position.
- Connect a fused (5A) jumper wire between the oil pressure switch C103-1, circuit CMC24 (GY), harness side and ground.
  
  Fig 1: Monitoring Low Oil Pressure Warning Indicator
  Courtesy of FORD MOTOR CO.
- Does the low oil pressure warning indicator illuminate with the jumper wire disconnected, and turn off with the jumper wire connected?
Yes : DISCONNECT the jumper wire. GO to O3.

No : If the oil pressure indicator is never on, DISCONNECT the jumper wire. GO to O5.

If the oil pressure indicator is always on, DISCONNECT the jumper wire. GO to O4.
O3 CARRY OUT THE ENGINE OIL PRESSURE TEST
- Carry out the engine oil pressure test. Refer to ENGINE SYSTEM-GENERAL INFORMATION .
- Is the engine oil pressure within specification?
Yes : INSTALL a new oil pressure switch. REFER to ENGINE - 2.3L , or ENGINE - 3.0L (4V) . TEST the system for normal operation.

No : REFER to ENGINE SYSTEM-GENERAL INFORMATION to continue diagnosis of the engine oil pressure system.
O4 CHECK CIRCUIT CMC24 (GY) FOR AN OPEN
- Key in OFF position.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-26, circuit CMC24 (GY), harness side and the oil pressure switch C103-1, circuit CMC24 (GY), harness side.
  
  Fig 2: Checking Circuit CMC24 (GY) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to O6.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
O5 CHECK CIRCUIT CMC24 (GY) FOR A SHORT TO GROUND
- Measure the resistance between the SJB C2280a-26, circuit CMC24 (GY), harness side and ground.
  
  Fig 3: Checking Circuit CMC24 (GY) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes : GO to O6.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
O6 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - Corrosion
  - 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 MULTIFUNCTION ELECTRONIC CONTROL MODULES . 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.
O7 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect the instrument cluster connector.
- Check for:
  - Corrosion
  - Pushed-out pins
- Connect the 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 instrument cluster. REFER to INSTRUMENT CLUSTER . 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.