GM Service Manual Online
For 1990-2009 cars only

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 oil pressure is high, the sensor resistance is high, and the ECM senses a high signal voltage. When the 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 instrument panel cluster (IPC) via the class 2 serial data circuit.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The ECM does not detect a change in the engine oil pressure of at least 34.5 kPa (5.0 psi) over a predetermined variance of the engine speed.

Action Taken When the DTC Sets

    • The ECM records the operating conditions at the time the diagnostic test fails. The ECM displays this information in the Failure Records on the scan tool.
    • The IPC illuminates the engine oil pressure indicator.

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 ECM receives a 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 determine how many miles since the DTC set. The Fail Counter and 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.

Step

Action

Values

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Instrument Cluster Diagnostic System Check?

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Go to Step 2

Go to Symptoms - Instrument Panel, Gages and Console

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine ON.
  3. With the scan tool, observe the Engine Oil Pressure Sensor parameter in the ECM IPC Data list.

Does the Engine Oil Pressure Sensor parameter display values that vary within the specified values when idling and accelerating the engine?

0.7-2.5 V

Go to Diagnostic Aids

Go to Step 3

3

Replace the engine oil pressure (EOP) sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 4.6L.

Did you complete the replacement?

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Go to Step 4

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4

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

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Go to Step 2

System OK