GM Service Manual Online
For 1990-2009 cars only

Engine Oil Pressure Gage Inaccurate or Inoperative 4.2L

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views, Powertrain Control Module Connector End Views for the 4.2L engine

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Start the engine.

Does the engine oil pressure gage display at or below 0 psi (0 kPa)?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Install a scan tool.
  2. Turn ON the ignition.
  3. With the scan tool, observe the Engine Oil Pressure Switch parameter in the powertrain control module (PCM) Engine Data 3 data list.

Does the Engine Oil Pressure Switch parameter display Ok?

Go to Step 10

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the engine oil pressure (EOP) switch.
  3. Start the engine.
  4. With the scan tool, observe the Engine Oil Pressure Switch parameter.

Does the Engine Oil Pressure Switch parameter display Ok?

Go to Step 6

Go to Step 5

5

Test the signal circuit of the engine oil pressure switch for a short to ground. Refer to Circuit Testing and to Wiring Repairs.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

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

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

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Replace the engine oil pressure switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement for the 4.2L engine.

Did you complete the replacement?

Go to Step 11

--

9

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

Did you complete the replacement?

Go to Step 11

--

10

Replace the instrument panel cluster (IPC). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Engine Oil Pressure Gage Inaccurate or Inoperative 5.3L and 6.0L

Step

Action

Values

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views, Engine Control Module Connector End Views for the 5.3L engine or Engine Control Module Connector End Views for the 6.0L engine

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Start the engine.

Does the engine oil pressure (EOP) gage display within the specified range?

207-483 kPa (30-70 psi)

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Install a scan tool.
  2. Turn the ignition ON, 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 EOP gage move up and down when commanded?

--

Go to Step 4

Go to Step 10

4

  1. Turn the ignition OFF.
  2. Disconnect the negative battery cable.
  3. Disconnect the EOP sensor.
  4. 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 6

Go to Step 5

5

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

Did you find and correct the condition?

--

Go to Step 11

Go to Step 7

6

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.

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 powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

8

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

Did you complete the replacement?

--

Go to Step 11

--

9

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

Did you complete the replacement?

--

Go to Step 11

--

10

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

Did you complete the replacement?

--

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2