Circuit Description
The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The powertrain control module (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 normal range of the oil pressure sensor signal circuit is 0.5 volts at 0 kPa (0 psi) to 4.5 volts at 883 kPa (128 psi). The PCM sends the engine oil pressure information to the instrument panel cluster (IPC) via the class 2 serial data circuit in order to control the engine oil pressure gage.
Conditions for Running the DTC
| • | DTC P0641 is not set. |
| • | The engine is running. |
Conditions for Setting the DTC
| • | The PCM detects that the oil pressure 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 EOP gage displays 0 kPa (0 psi). |
| • | 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. |
Conditions for Clearing the DTC
| • | 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. |
Diagnostic Aids
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.
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 Engine Oil Pressure Sensor parameter display greater than the specified value? | 4.6 V | Go to Step 3 | Go to Diagnostic Aids |
Does the Engine Oil Pressure Sensor parameter display less than the specified value? | 0.4 V | Go to Step 5 | Go to Step 4 | |
4 | Test the oil 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 9 | Go to Step 6 |
5 | 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 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the powertrain control module (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 9 | Go to Step 8 |
7 | Replace the EOP sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 3.8L. 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 - 3.8L. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
