GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine oil pressure (EOP) sensor is mounted in the top rear of the engine. The EOP sensor measures changes in engine oil pressure. The EOP sensor has a 5-volt reference, a ground and a signal circuit. The EOP sensor changes resistance based on engine oil pressure and is used to determine when the oil pressure is below a certain threshold. When the oil pressure reaches a predetermined value, the powertrain control module (PCM) will determine this as low oil pressure. The PCM will then send a serial data message to the Instrument to activate the Check Oil warning icon. When the PCM senses a signal voltage lower than the normal operating range of the sensor, DTC P0522 will set.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

    • The powertrain control module (PCM) detects that the EOP sensor signal circuit is less than 0.48 volts.
    • The above condition is present for greater than 9 seconds.

Action Taken When the DTC Sets

    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM records the operating conditions at the time the diagnostic fails.
    • The PCM stores this information in the Failure Records.
    • The multifunction display (MFD) in the instrument cluster will display a message at key-on and key-off.

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 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.
    • The PCM 5-volt reference circuits are internally connected within the PCM. If all the Engine Oil sensor circuits check to be OK, inspect related 5-volt reference circuits. Refer to DTC P0641
    • If there is a failure with the Check Oil icon, more than likely it is an instrument cluster fault.
    • 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 the distance travelled since the DTC reported a pass and/or fail. Operate the vehicle within the same Failure Records conditions (RPM, load, vehicle speed, temperature, etc.) that you observed. This will isolate when the DTC failed.
    • For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

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 the ignition ON, with the engine OFF.
  3. With the scan tool, observe the Engine Oil Pressure Sensor parameter in the powertrain control module (PCM) Engine Data 3 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

Is DTC P0641 current in the PCM?

--

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-ampere 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 Engine Oil Pressure Sensor parameter.

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

4.6 V

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 for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

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, for a short to ground, or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

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 in Wiring Systems.

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

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

Did you complete the replacement?

--

Go to Step 12

--

11

Important: Program the replacement PCM.

Replace the PCM. Refer to Engine Control Module Replacement in Engine Controls - 5.7L.

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