GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine oil pressure switch closes and the signal circuit is low with low oil pressure. The engine oil pressure switch opens and signal circuit is high with oil pressure above 4.5 psi. The powertrain control module (PCM) monitors the oil pressure switch signal circuit and sends a class 2 message to the body control module (BCM) indicating the switch status. The BCM sends a message via the class 2 serial data circuit to the instrument panel cluster (IPC) in order to illuminate the low oil pressure indicator.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0520 Engine Oil Pressure (EOP) Sensor Circuit

Conditions for Running the DTC

    • The following DTCs are not set:
       - P0117
       - P0118
       - P1111
       - P1114
    • The ignition is ON, with the engine OFF.
    • The engine temperature is 10°C (50°F) less than the last key OFF temperature.

Conditions for Setting the DTC

    • The PCM detects that the oil pressure switch signal circuit is high.
    • The above condition is present for greater than 10 seconds.

Action Taken When the DTC Sets

The PCM stores the conditions that are present when the DTC sets as Failure Records data only. This information is not stored as Freeze Frame data.

Conditions for Clearing the DTC

    • The DTC becomes history when then conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives the clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Engine Oil Pressure Switch parameter in the PCM Engine 3 Data List - 2.2L or Engine 2 Data List - 3.4L.

Does the Engine Oil Pressure Switch parameter display Low?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn the ignition OFF.
  2. Disconnect the engine oil pressure switch.
  3. Connect a fused jumper wire between the oil pressure switch signal circuit and a good ground.
  4. Turn the ignition ON, with the engine OFF.
  5. With a scan tool, observe the Engine Oil Pressure Switch parameter in the PCM Engine 3 Data List - 2.2L or Engine 2 Data List - 3.4L.

Does the Engine Oil Pressure Switch parameter display Low?

Go to Step 5

Go to Step 4

4

Test the signal circuit of the engine oil pressure switch for an open, for a high resistance, or 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 10

Go to Step 7

5

Test the case ground of the engine oil pressure switch for a high resistance or for a poor connection. Refer Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the engine oil pressure switch. 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 10

Go to Step 8

7

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 10

Go to Step 9

8

Replace the engine oil pressure switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 2.2L or to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 3.4L.

Did you complete the replacement?

Go to Step 10

--

9

Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

10

  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