Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2
Tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.
- 3
Tests for proper power and ground at the front axle actuator.
- 4
Tests the operation of the front axle control circuit.
- 5
Tests the electrical function of the front axle actuator control circuit.
- 6
Tests for proper supply voltage to the front axle actuator.
- 7
Tests for open fuse in the front axle feed circuit.
- 8
Tests the front axle control circuit for an open or high resistance.
- 9
Tests the front axle switch circuit for an open or high resistance.
- 10
Helps determine if the front axle actuator has a mechanical malfunction.
- 11
Tests the front axle switch circuit for a short to voltage.
- 12
Inspect the front axle for a mechanical malfunction.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Transfer Case Control Schematics | ||||
| 1 | Was the Transfer Case Diagnostic System Check performed? | - | Go to Step 2 | Go to Diagnostic System Check - Transfer Case |
| 2 |
|
- | Go to Step 10 | Go to Step 3 |
| 3 |
|
9-14 V | Go to Step 4 | Go to Step 6 |
| 4 |
|
- | Go to Step 5 | Go to Step 8 |
| 5 |
|
- | Go to Step 15 | Go to Step 9 |
| 6 | Measure the voltage between the front axle feed circuit and ground. Is the voltage reading within the specified values? |
9-14 V | Go to Step 13 | Go to Step 7 |
| 7 | Test for open fuse in the front axle feed circuit. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Was the condition found and corrected? |
- | Go to Step 17 | Go to Step 14 |
| 8 | Test the front axle control circuit for an open or high resistance. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Was the condition found and corrected? |
- | Go to Step 17 | Go to Step 16 |
| 9 | Test the front axle switch circuit for an open or high resistance. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Was the condition found and corrected? |
- | Go to Step 17 | Go to Step 16 |
| 10 |
|
- | Go to Step 11 | Go to Step 12 |
| 11 | Test the front axle switch circuit for a short to voltage. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Was the condition found and corrected? |
- | Go to Step 17 | Go to Step 16 |
| 12 | Inspect the front axle for a mechanical malfunction. Was the condition found and corrected? |
- | Go to Step 17 | Go to Step 16 |
| 13 | Repair an open in the front axle ground circuit. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Is the repair complete? |
- | Go to Step 17 | - |
| 14 | Repair an open in the front axle feed circuit. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Is the repair complete? |
- | Go to Step 17 | - |
| 15 | Replace the front axle switch/actuator. Refer to Electric Motor Actuator Replacement
. Is the repair complete? |
- | Go to Step 17 | - |
| 16 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the repair complete? |
- | Go to Step 17 | - |
| 17 |
|
- | Go to Step 2 | System OK |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.