The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The PCM monitors the signal circuit of the EOP sensor. When the oil pressure is high, the sensor resistance is high and the PCM senses a high signal voltage. When the oil pressure is low, the sensor resistance is low and the PCM senses a low signal voltage. The PCM sends the engine oil pressure information to the IPC via the class 2 serial data circuit.
• | The engine is running. |
• | P1635 is not set. |
• | The PCM detects that the EOP sensor signal circuit is less than 0.3 volts. |
• | The above condition is present for greater than 9 seconds. |
• | The PCM records the operating conditions at the time the diagnostic fails. The PCM displays this information in the Failure Records on the scan tool. |
• | The instrument panel cluster (IPC) illuminates the engine oil pressure indicator, and the DIC displays LOW OIL PRESSURE. |
• | The DTC becomes history when the conditions for setting the DTC are no longer present. |
• | The history DTC clears after 40 malfunction free warm-up cycles. |
• | The PCM receives a clear code command from the scan tool. |
Using the Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail.
Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Instrument Cluster Schematics | |||
1 | Did you perform the Instrument Cluster Diagnostic System Check? | Go to Step 2 | |
2 |
Does the Engine Oil Pressure Switch parameter change from Low to OK? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 |
Does the Engine Oil Pressure Switch parameter indicate OK? | Go to Step 5 | Go to Step 4 |
4 | Test the engine oil pressure signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the engine oil pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the engine oil pressure sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 4.0L. Did you complete the replacement? | Go to Step 9 | -- |
8 |
Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.0L. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |