GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Master Electrical Component List

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 a scan tool, perform the Displays Test in the instrument panel cluster (IPC) Scan Tool Output Controls.

Does the engine oil pressure gage move up and down when commanded?

--

Go to Step 3

Go to Step 14

3

  1. Turn the ignition OFF.
  2. Disconnect the 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 one of the following engine oil pressure parameters:
  5. • Monitored Oil Pressure parameter in the IPC Data 1 data list - 6.6L diesel only.
    • Engine Oil Pressure Sensor parameter in the powertrain control module (PCM) Engine Data 2 data list - All engines except 6.6L diesel.

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

550 kPa (80 psi) - 6.6L diesel only

4.6 V - All engines except 6.6L diesel

Go to Step 4

Go to Step 5

4

  1. Connect a 3-amp fused jumper between the EOP sensor signal circuit and the low reference circuit of the EOP sensor.
  2. With the scan tool, observe one of the following engine oil pressure parameters:
  3. • Monitored Oil Pressure parameter in the IPC Data 1 data list - 6.6L diesel only.
    • Engine Oil Pressure Sensor parameter in the PCM Engine Data 2 data list - All engines except 6.6L diesel.

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

0 kPa (0 psi) - 6.6L diesel only

0.4 V - All engines except 6.6L diesel

Go to Step 10

Go to Step 6

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 9

Go to Step 7

6

  1. Disconnect the negative battery cable.
  2. Measure the resistance from the low reference circuit of the EOP sensor to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 11

Go to Step 8

7

Test the EOP 5-volt reference circuit for the following:

    • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 8

8

Test the EOP low reference circuit for high resistance or for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 9

9

Test the EOP oil pressure sensor signal circuit for the following:

    • An open
    • A short to ground
    • A high resistance

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

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

10

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 15

Go to Step 12

11

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12

Replace the engine oil pressure sensor. Refer to the following procedures:

    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 4.8L, 5.3L and 6.0L engines
    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 6.6L (LLY) engine

Did you complete the replacement?

--

Go to Step 15

--

13

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

Did you complete the replacement?

--

Go to Step 15

--

14

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

Did you complete the replacement?

--

Go to Step 15

--

15

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2