GM Service Manual Online
For 1990-2009 cars only

Object Number: 601187  Size: SF
Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The oil level switch is a float style switch which is closed with oil level full and open when oil level is low. The PCM monitors the oil level switch to determine if the oil is LOW or OK. When the Test Conditions have been met the PCM will monitor the oil level switch input. If a low oil level is indicated the PCM will ground the Low Oil Level Indicator control circuit turning on the Low Oil Level Indicator within the Instrument Panel (IP) Cluster. The engine coolant temperature Test Condition is required to ensure enough time has passed since the engine was last stopped. The time period/coolant temperature difference is to allow enough time for the engine oil to drain back into the oil pan. The colder the engine temperature is, the larger the drop in temperature necessary. This is to ensure colder, thicker oil has drained back into the oil pan.

Diagnostic Aids

Inspect for the following:

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

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.

    • Loose terminal connection
       -  Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
       -  Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in 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 Repairs in Wiring Systems for diagnosis and repair.
    •  Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

Test Description

  1. The Powertrain On Board Diagnostic (OBD) System Check must be performed before proceeding with this diagnosis. Refer to any DTCs that are set first.

  2. With the engine speed at or above 2300 RPM the engine oil switch should indicate LOW oil level. The engine oil is scavenged to a level that is below the switch during higher engine speed and also during some lateral vehicle movement conditions.

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Does the scan tool indicate DTC P1653 is set?

--

Go to DTC P1653 Low Engine Oil Level Lamp Control Circuit

Go to Step 3

3

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

Is the engine oil level low?

--

Go to Oil Consumption Diagnosis in Engine Mechanical

Go to Instrument Cluster System Check in Instrument Panel Gauges and Console