Test Description
WARNING: This page is about a different car, the 2007 Hummer H2. 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: This step determines if the differential lock is engaged due to an electrical condition or a mechanical condition.
- 3: This step determines if the differential lock high control circuit is shorted to power and if the differential low reference circuit is shorted to ground.
- 4: This step indicates the transfer case shift control module needs replaced.
- 5: This step checks for the possibility of the rear differential mechanically binding causing it to stay on.
Electronic Rear Differential Lock Will Not Disengage
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Differential Lock Schematics Connector End View Reference: Rear Axle Connector End Views |
|||
| 1 | Did you perform the Diagnostic System Check-Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Disconnect the rear differential lock harness from the rear differential lock coil pigtail at the rear differential, and verify the fault is present. Refer to Locking Differential Diagnosis . Does the system operate normally? |
Go to Step 3 | Go to Step 5 |
| 3 | Check the rear differential lock high control circuit for a short to power and the differential lock low reference for a short to ground. Refer to Circuit Testing
and Wiring Repairs
. Was the condition found and corrected? |
Go to Step 6 | Go to Step 4 |
| 4 | Replace the transfer case shift control module. Refer to Control Module References
for replacement, setup, and programming. Was the repair completed? |
Go to Step 6 | - |
| 5 | Replace the electronic locking differential locking mechanism and/or side gear. Refer to Locking Differential Disassemble and Locking Differential Assemble . Was the condition repaired? |
Go to Step 6 | - |
| 6 |
|
Go to Step 1 | System OK |