For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Controls Schematics
1 | Did you perform the Instrument Cluster Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Instrument Cluster
2 | Start the engine. Does the engine oil pressure indicator illuminate after the displays test? | Go to Step 3 | Go to Intermittents and Poor Connections Diagnosis in Wiring Systems
3 |

1. Install a scan tool.
2. With a scan tool, observe the Engine Oil Pressure Switch parameter in the PCM IPC data list.

Does the Engine Oil Pressure Switch parameter display OK?

Go to Step 10

Go to Step 4

4 |

1. Turn the ignition OFF.
2. Disconnect the engine oil pressure switch.
3. Start the engine.
4. With the scan tool, observe the Engine Oil Pressure Switch parameter.

Does the Engine Oil Pressure Switch display OK?

Go to Step 6

Go to Step 5

5 | Test the oil pressure switch signal circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 7
6 | Inspect for poor connections at the harness connector of the engine oil pressure switch. Refer to Intermittents and Poor Connections Diagnosis and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 8
7 | Inspect for poor connections at the harness connector of the PCM. Refer to Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 9
8 | Replace the engine oil pressure switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement . Did you complete the replacement? | Go to Step 11 | --
9 | Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Did you complete the replacement? | Go to Step 11 | --
10 | Replace the IPC. Refer to Instrument Cluster Replacement . Did you complete the replacement? | Go to Step 11 | --
11 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2