GM Service Manual Online
For 1990-2009 cars only

Engine Oil Pressure Indicator Always On 3.5L

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views , and Powertrain Control Module Connector End Views in Engine Controls - 3.5L

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Start the engine.

Does the engine oil pressure indicator illuminate after the displays test?

Go to Step 3

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

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 instrument panel cluster (IPC) powertrain control module (PCM) 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 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 in Wiring Systems.

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 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 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 in Wiring Systems.

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 in Engine Mechanical - 3.5L.

Did you complete the replacement?

Go to Step 11

--

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 11

--

10

Replace the IPC. Refer to Control Module References in Computer/Integrating Systems 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 Indicator Always On 3.6L

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

Does the engine oil pressure (EOP) indicator display in the message center?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Engine Oil Pressure Sensor parameter in the engine control module (ECM) instrument panel cluster (IPC) Data list.

Is the Engine Oil Pressure Sensor parameter within the specified range?

207-483 kPa (30-70 psi)

Go to Step 15

Go to Step 4

4

  1. Turn the ignition OFF.
  2. Disconnect the 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 in the ECM IPC Data list.

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

550 kPa (80 psi)

Go to Step 5

Go to Step 6

5

  1. Connect a 3-ampere fused jumper between the EOP sensor signal circuit and the low reference circuit of the EOP sensor.
  2. With the scan tool, observe the Engine Oil Pressure Sensor parameter in the ECM IPC Data list.

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

0 kPa (0 psi)

Go to Step 11

Go to Step 7

6

  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 10

Go to Step 8

7

  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 12

Go to Step 9

8

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 16

Go to Step 9

9

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 16

Go to Step 10

10

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 16

Go to Step 12

11

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 16

Go to Step 13

12

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

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

13

Replace the engine oil pressure sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement for the 3.6L engine.

Did you complete the replacement?

--

Go to Step 16

--

14

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

Did you complete the replacement?

--

Go to Step 16

--

15

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

Did you complete the replacement?

--

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2