Test Description
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests for an intermittent condition.
- 3: Determines whether the failure is the result of a faulty 4WD system.
- 4: Determines if the failure is the result of a faulty instrument cluster.
- 5: Determines if the failure is the result of a faulty PCM.
Four-Wheel Drive Indicator Always On
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Transfer Case Control Schematics | ||||
| 1 | Did you perform A Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Verify the fault is present. Does the system operate normally? |
- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
| 3 | Does the front axle disengage when the 4WD control lever is in the 2WD position? | - | Go to Step 4 | Go to Four-Wheel Drive Does Not Disengage |
| 4 |
|
- | Go to Step 5 | Go to Step 8 |
| 5 | Test the axle switch signal circuit for voltage at the PCM. Does the voltage measure within the specified value? |
9-14 V | Go to Step 6 | Go to Step 7 |
| 6 |
|
- | Go to Step 9 | - |
| 7 | Replace the PCM. Refer to Control Module References
for replacement, set-up, and programming. Did you complete the replacement? |
- | Go to Step 9 | - |
| 8 | Replace the instrument panel cluster. Refer to Instrument Cluster Replacement (without RPO SLT)
or Instrument Cluster Replacement (with RPO SLT)
. Did you complete the replacement? |
- | Go to Step 9 | - |
| 9 | Operate the vehicle in order to determine if the symptom has been corrected. Is the symptom still present? |
- | System OK | Go to Step 2 |