Circuit Description
The engine oil level switch is a simple float switch that is grounded when the engine oil level is OK. The powertrain control module (PCM) checks the engine oil level switch circuit at start-up. Before checking the state of the engine oil level switch, the PCM performs a test routine based on time and engine coolant temperature (ECT) 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 ECT must be more than 15°C (59°F). |
| • | The ECT 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 the Instrument Cluster section of Electrical Diagnosis. Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges & Console.
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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: This table assumes that the oil level is at the proper level or the oil level was low and the Low Oil Level message was never displayed. Check for BCM DTCs. With a scan tool, observe the Oil Level parameter. Does the scan tool indicate OK? | -- | ||
3 |
Does the scan tool indicate LOW when the switch is disconnected? | -- | Go to Diagnostic Aids | |
4 |
Does the scan tool indicate OK when the jumper is installed? | -- | ||
5 |
Does the scan tool indicate OK when the jumper is installed? | |||
6 | Probe the signal circuit using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | ||
7 | Test for a short to ground on the signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | System OK | |
8 | Test for a short to voltage on the signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | System OK | |
9 | Repair the open in the ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- |
10 | Test for an open in the signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | System OK | |
11 | Inspect for faulty connections at the switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | System OK | |
12 | Replace the oil level switch. Refer to Engine Oil Level Sensor and/or Switch Replacement . Is the action complete? | -- | System OK | -- |
13 |
Did you find and correct the condition? | -- | System OK | |
14 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | System OK | -- |
