For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Instrument Cluster 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 Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3 |

1. Install a scan tool.
2. With a scan tool, observe the Low Oil Pressure parameter in the Powertrain General Info -- Inputs list.

Does the Low Oil Pressure parameter display No?

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 Low Oil Pressure parameter.

Does the Low Oil Pressure parameter display Yes?

Go to Step 6

Go to Step 5

5 | Test the signal circuit of the oil pressure switch signal for a short to ground. Refer to Circuit Testing and to 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 Testing for Intermittent Conditions and Poor Connections and to Connector Repairs 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 ECM/PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to 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 in Engine Mechanical - 2.2 L or to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical -- 3.0 L. Did you complete the replacement? | Go to Step 11 | --
9 | Important: Program the replacement ECM/PCM. Replace the ECM/PCM. Refer to Engine Control Module Replacement in Engine Controls -- 3.0L or to Powertrain Control Module Replacement in Engine Controls -- 2.2L. 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