Circuit Description
The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The engine control module (ECM) monitors the signal circuit of the EOP sensor. When the engine oil pressure is high, the sensor resistance is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the sensor resistance is low and the ECM senses a low signal voltage. The ECM sends the engine oil pressure information to the IPC via the class 2 serial data circuit.
Conditions for Running the DTC
| • | The engine is running. |
| • | DTC P0641 is not present. |
Conditions for Setting the DTC
| • | The ECM detects that the EOP sensor signal circuit is greater than 4.6 volts. |
| • | The above condition is present for greater than 9 seconds. |
Action Taken When the DTC Sets
The ECM records the operating conditions at the time that the diagnostic test fails. The ECM displays this information in the Failure Records on the scan tool.
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC is cleared after 40 malfunction-free warm-up cycles. |
| • | The ECM receives the clear code command from the scan tool. |
Diagnostic Aids
Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help in determining how many miles since the DTC set. The Fail Counter and the Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics | ||||
1 | Did you perform the Instrument Cluster Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate that the Monitored Oil Pressure parameter is at or greater than the specified value? | 550 kPa (80 psi) | Go to Step 3 | Go to Diagnostic Aids |
Does the scan tool indicate that the Monitored Oil Pressure parameter is at or less than the specified value? | 0 kPa (0 psi) | Go to Step 4 | Go to Step 5 | |
4 |
Is the resistance less than the specified value? | 5 ohms | Go to Step 7 | Go to Step 6 |
5 | Test the EOP sensor signal circuit for a short to voltage. 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 8 |
6 |
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 EOP sensor. 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 | Inspect for poor connections at the harness connector of the ECM. 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 10 |
9 | Replace the EOP sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 7.8L. Did you complete the replacement? | -- | Go to Step 11 | -- |
10 |
Important: Program the replacement ECM. Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data in Engine Controls - 7.8L. Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
