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 monitor (ECM) monitors the signal circuit of the EOP sensor. When the engine oil pressure is high, the sensor resistance is high, and the ECM senses a high signal voltage. When the engine 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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0522 Engine Oil Pressure (EOP) Sensor Circuit Low Voltage

Conditions for Running the DTC

    • The engine is running.
    • DTC P0641 is not present.

Conditions for Setting the DTC

    • The ECM detects that the EOP sensor signal circuit is less than 0.4 volts.
    • The above condition is present for greater than 9 seconds.

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.

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 .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests for the proper operation of the circuit in the high voltage range.

Step

Action

Values

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

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the Monitored Oil Pressure parameter in the instrument panel cluster (IPC) data list.

Does the scan tool indicate that the Monitored Oil Pressure parameter is at or less than the specified value?

0 kPa (0 psi)

Go to Step 3

Go to Diagnostic Aids

3

Is DTC P0641 current in the engine control module (ECM)?

--

Go to DTC P0641

Go to Step 4

4

  1. Turn the ignition OFF.
  2. Disconnect the engine oil pressure (EOP) sensor.
  3. Connect a 3-amp fused jumper between the EOP sensor signal circuit and the 5-volt reference circuit of the EOP sensor.
  4. With the scan tool, observe the Monitored Oil Pressure parameter in the IPC data list.

Does the scan tool indicate that the Monitored Oil Pressure parameter is at or greater than the specified value?

550 kPa (80 psi)

Go to Step 8

Go to Step 5

5

  1. Disconnect the fused jumper.
  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 7

Go to Step 6

6

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

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7

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

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 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 ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the EOP sensor.

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 12

--

12

  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?

--

Go to Step 2

System OK