<p> Front Axle Will Not Disengage </p><p>Circuit Description</p><p>The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly. The front axle actuator has four circuits connected: • Ignition 3 voltage circuit • Ground circuit • Axle actuator control circuit • Axle switch signal circuit Whenever a shift to 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the axle actuator control circuit through a current limiting driver.</p><p>Test Description</p><p>The numbers below refer to the step numbers on the diagnostic table.</p><p>2. This step tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.</p><p>3. This step tests for proper power and ground at the front axle actuator.</p><p>4. This step tests the operation of the axle actuator control circuit.</p><p>5. This step tests the electrical function of the axle actuator control circuit.</p><p>6. This step tests for proper ignition 3 voltage to the front axle actuator.</p><p>7. This step tests for open fuse in the ignition 3 voltage circuit.</p><p>8. This step tests the axle actuator control circuit for an open or high resistance.</p><p>9. This step tests the axle switch signal circuit for an open or high resistance.</p><p>10.This step helps determine if the front axle actuator has a mechanical malfunction.</p><p>11.This step tests the axle switch signal circuit for a short to voltage.</p><p>12.Inspect the front axle for a mechanical malfunction.</p><p>Step Action Value(s) Yes No Schematic Reference: 1 Was the Transfer Case Diagnostic System -- Go to Go to Diagnostic Check performed? Step 2 System Check - Transfer Case 1. Turn ON the ignition, with the engine OFF. 2. Ensure that the vehicle is in 2WD mode. 3. Install a scan tool. 4. Use the scan tool in order to read the Front 2 -- Axle Switch Status.</p><p>Does the scan tool display the Front Axle Switch Go to status as Locked? Step 10 Go to Step 3 1. Turn OFF the ignition. 2. Disconnect the front axle actuator. 3. Turn ON the ignition, with the engine OFF. 4. Measure the voltage between the ignition 3 3 voltage circuit and the ground circuit at the 9-14 V front axle actuator.</p><p>Does the voltage measure within the specified Go to values? Step 4 Go to Step 6 1. Connect a test lamp between the ignition 3 voltage circuit and the axle actuator control circuit at the front axle actuator. 4 2. Observe the test lamp, while using the scan -- tool in order to engage the front axle. Go to Does the test lamp illuminate? Step 5 Go to Step 8 1. Connect a fused jumper wire between the ignition 3 voltage circuit and the axle switch signal circuit. 2. Use the scan tool in order to read the Front 5 -- Axle Switch status.</p><p>Does the scan tool display the Front Axle Switch Go to status Locked? Step 15 Go to Step 9 Measure the voltage between the ignition 3 voltage circuit and ground. 6 9-14 V Does the voltage measure within the specified Go to values? Step 13 Go to Step 7 Test for open fuse in the ignition 3 voltage 7 circuit. -- Go to Did you find and correct the condition? Step 17 Go to Step 14 Test the axle actuator control circuit for an open 8 or high resistance. -- Go to Did you find and correct the condition? Step 17 Go to Step 16 Test the axle switch signal circuit for an open or 9 high resistance. -- Go to Did you find and correct the condition? Step 17 Go to Step 16 10 1. Disconnect the front axle actuator. -- Go to Go to Step 12 2. Use the scan tool in order to read the Front Step 11 Axle Switch status.</p><p>Does the scan tool display the Front Axle Switch status Locked? Test the axle switch signal circuit for a short to 11 voltage -- Go to Did you find and correct the condition? Step 17 Go to Step 16 Inspect the front axle for a mechanical 12 malfunction. -- Go to Did you find and correct the condition? Step 17 Go to Step 16 Repair an open in the ground circuit. Go to 13 -- Did you complete the repair? Step 17 -- Repair an open in the ignition 3 voltage circuit. Go to 14 -- Did you complete the repair? Step 17 -- Replace the front axle actuator. Refer to the 15 Electric Motor Actuator Replacement . -- Go to Did you complete the replacement? Step 17 -- Replace the transfer case shift control module. Go to 16 Did you complete the replacement? -- Step 17 -- 1. Use the scan tool in order to clear the DTCs . 2. Operate the vehicle within the conditions for 17 allowing the symptom to re-occur. Go to Does the symptom re-occur? -- Step 2 System OK</p>