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 engine oil pressure is high, the sensor resistance is high and the PCM senses a high signal voltage. When the engine 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 instrument panel cluster (IPC) via the class 2 serial data circuit.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0523 Engine Oil Pressure (EOP) Sensor Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON. |
| • | DTC P1635 (LBZ, LLY, LMM, and late L18) or DTC P0641 (early L18 and LG4) is present. |
Conditions for Setting the DTC
| • | The PCM 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 PCM records the operating conditions at the time that the diagnostic test 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 is cleared after 40 malfunction-free warm-up cycles. |
| • | The PCM 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 .
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Master Electrical Component List | ||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Does the scan tool indicate that the Engine Oil Pressure parameter is at or greater than the specified value? | 4.6 V | Go to Step 3 | Go to Diagnostic Aids | ||||
3 | Is DTC P1635 (LLY and late L18) or DTC P0641 (early L18 and LG4) current in the PCM? | -- | Go to Step 4 | |||||
Does the scan tool indicate that the Engine Oil Pressure parameter is at or less than the specified value? | 0.4 V | Go to Step 5 | Go to Step 6 | |||||
5 |
Is the resistance less than the specified value? | 5 ohms | Go to Step 8 | Go to Step 7 | ||||
6 | Test the EOP sensor signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||
7 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||
8 | 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 . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 | ||||
9 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 | ||||
10 | Replace the EOP sensor. Refer to one of the following procedures:
Did you complete the replacement? | -- | Go to Step 12 | -- | ||||
11 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- | ||||
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||
