GM Service Manual Online
For 1990-2009 cars only

Refer to Engine Controls Schematic

IAC, I/P, Engine Oil Level Indicator Switch and PNP


Object Number: 588228  Size: FS
G100, G111 and G113
G100, G111 and G113
G117
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Actuator and Ground Feed
Engine Controls Components
Powertrain Control Module Description
Automatic Transaxle and Stop Lamp Switch
I/P, Generator and Driver Information Display
OBD II Symbol Description Notice
.

Circuit Description

The Engine Oil Level Switch is a simple float switch that is grounded when the engine oil level is OK. The PCM checks the Engine Oil Level switch circuit at startup. Before checking the state of the Engine Oil Level switch, the PCM performs a test routine based on time and engine coolant temperature to ensure that the engine oil has drained back into the sump. To test for low oil level at start-up, both of the following conditions must be present:

    •  The engine coolant temperature must be greater than 15°C (59°F).
    •  The engine coolant temperature at key ON must be at least 12°C (22°F) cooler than the engine coolant temperature at the last key OFF.

Diagnostic Aids

For diagnosis of the instrument panel, perform the System Check in Instrument Panel, Gauges and Console.

Check for the following conditions:

Important: :  Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

    •  Poor terminal connection.
        Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Wiring Systems for diagnosis and repair.
    •  Damaged harness.
        Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Systems for diagnosis and repair.
    •  Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

Test Description

Numbers below refer to the step numbers on the Diagnostic Chart:

  1. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

  2. For the PCM to check engine oil level, start-up engine coolant temperature must be at least 12°C (22°F) cooler than the engine coolant temperature was last time the ignition was turned off. Allowing the engine to warm and then cool ensures that the PCM checks the engine oil level switch and that the information displayed on the scan tool is current.

Engine Oil Level Switch Diagnosis

Step

Action

Values

Yes

No

1

Important: :  Ensure that engine oil level is not low, before continuing diagnosis. Refer to Approximate Fluid Capacities in Maintenance and Lubrication.

Was the Powertrain OBD System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Observe oil level parameter on the scan tool.

Does oil level parameter indicate OK?

--

Go to Applicable DTCs

Go to Step 3

3

  1. Turn the ignition off.
  2. Disconnect the PCM.
  3. With a test lamp to battery positive voltage, probe the oil level switch signal circuit at the PCM.

Is the test lamp on?

--

Go to Step 7

Go to Step 4

4

  1. Turn the ignition off.
  2. Reconnect the PCM.
  3. Turn the ignition on.
  4. Raise the vehicle.
  5. Disconnect the oil level switch connector.
  6. Connect DMM to measure voltage between the oil level switch terminals.

Does the DMM display voltage near the specified value?

B+

Go to Step 8

Go to Step 5

5

Connect the DMM between the oil level switch signal circuit and chassis ground.

Does the DMM display a voltage near the specified value?

B+

Go to Step 9

Go to Step 6

6

Test the oil level switch signal circuit for an open. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Diagnostic Aids

7

  1. Inspect for poor terminal connections at the PCM.
  2. If a problem is found, repair as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

8

Inspect for poor terminal connections at the oil level switch. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Locate and repair open in the oil level switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

--

10

Replace the oil level switch.

Did you complete the repair?

--

Go to Step 12

--

11

Important: :  Replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Did you complete the repair?

--

Go to Step 12

--

12

  1. Start the engine and allow it to warm until engine coolant temperature is at least 70° C (158° F).
  2. Turn on the ignition switch and allow the engine to cool for at least 15 minutes.
  3. Turn on the ignition switch.
  4. Observe the engine oil level display on the scan tool.

Does oil level display OK?

--

System OK

Go to Step 3