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Home >> GMC >> 2001 >> C3500 HD 6.5 F, Automatic >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays, Gauges And Console >> Diagnostic Information and Procedures >> Low Engine Oil Level Indicator Inoperative >> Circuit Description

Circuit Description

When the engine oil level is in the normal range, the engine oil level switch is a closed switch and the engine oil level switch signal is low.

When a low engine oil level condition is present, the engine oil level switch is an open switch and the engine oil level switch signal is high. The IPC receives a class 2 message from the PCM requesting illumination of the CHECK ENG OIL LEVEL indicator.

Low Engine Oil Level Indicator Inoperative

Step Action Value(s) Yes No
Schematic Reference:  Instrument Cluster Schematics  
1 Did you perform the Instrument Cluster Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Instrument Cluster 
2 Turn ON the ignition, with the engine OFF.
Does the low engine oil level indicator display in the message center?
- Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3
  1. Install a scan tool.
  2. With the scan tool select the PCM Engine Data 2 data list and observe the Engine Oil Level parameter.
Does the scan tool indicate that the Engine Oil Level parameter is low?
- Go to Step 8  Go to Step 4 
4
  1. Turn OFF the ignition.
  2. Disconnect the engine oil level switch.
  3. Turn ON the ignition, with the engine OFF.
Does the scan tool indicate that the engine oil level parameter is OK?
- Go to Step 5  Go to Step 6 
5 Test the signal circuit of the engine oil level switch for a short to ground. Refer to Circuit Testing , and 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 level switch. Refer to Testing for Intermittent Conditions and Poor Connections , and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 11  Go to Step 9 
7 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections , and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 11  Go to Step 10 
8 Replace the IPC. Refer to Instrument Cluster Replacement .
Did you complete the replacement?
- Go to Step 11  -
9 Replace the engine oil level switch. Refer to Engine Oil Level Sensor Replacement .
Did you complete the replacement?
- Go to Step 11  -
10
IMPORTANT:

Program the replacement PCM.

Replace the PCM. Refer to: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 3