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 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.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PCM detects that the oil pressure sensor signal circuit is less than 0.48 volts.

Action Taken When the DTC Sets

    • 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 malfunction indicator lamp (MIL) will not illuminate.
    • The EOP gauge displays 0 psi (0 kPa).

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(s) below refer to the step number(s) on the diagnostic table.

  1. This step tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Step

Action

Values

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, observe the Engine Oil Pressure Sensor parameter in the PCM Engine Data 2 data list.

Does the Engine Oil Pressure Sensor parameter display less than the specified value?

0.48 V

Go to Step 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the engine oil pressure (EOP) sensor connector.
  3. Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the EOP sensor and the oil pressure sensor signal circuit.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the Engine Oil Pressure Sensor parameter.

Does the Engine Oil Pressure Sensor parameter display greater than the specified value?

4.6 V

Go to Step 7

Go to Step 4

4

  1. Disconnect the fused jumper wire.
  2. Measure the voltage between the 5 volt reference circuit of the EOP sensor and the low reference circuit of the EOP sensor.

Does the voltage measure greater than the specified value?

4.6 V

Go to Step 6

Go to Step 5

5

Test the 5 volt reference circuit of the EOP sensor for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 8

6

Test the oil pressure sensor signal circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

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 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 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 11

Go to Step 10

9

Replace the EOP sensor. Refer to Engine Oil Pressure Sensor or Switch Replacement .

Did you complete the replacement?

--

Go to Step 11

--

10

Important: Program the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 8.1L.

Did you complete the replacement?

--

Go to Step 11

--

11

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

Does the DTC reset?

--

Go to Step 2

System OK