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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 85 (Transfer Case - ISUZU T150) >> Diagnostic Information and Procedures >> Front Axle Will Not Disengage >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Isuzu i-370, 2007 GMC Canyon, and 2007 Chevrolet Colorado. 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.

  1. 2:  This step tests the electrical function of the front axle actuator and helps determine mechanical and electrical malfunctions.
  2. 3:  This step tests for proper voltage and ground at the front axle actuator.
  3. 4:  This step tests the operation of the front axle actuator control circuit.
  4. 5:  This step tests the electrical function of the front axle actuator control circuit.
  5. 6:  This step tests for proper supply voltage to the front axle actuator.
  6. 7:  This step tests for open fuse in the ignition 3 voltage circuit.
  7. 8:  This step tests the front axle actuator control circuit for an open or high resistance.
  8. 9:  This step tests the front axle actuator signal circuit for an open or high resistance.
  9. 10:  This step helps determine if the front axle actuator has a mechanical malfunction.
  10. 11:  This step tests the front axle switch circuit for a short to voltage.
  11. 13:  This step inspects the front axle for a mechanical malfunction.
Front Axle Will Not Disengage

Step Action Values Yes No
Schematic Reference: Transfer Case Control Schematics 
Connector End View Reference: Transfer Case Control Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Ensure that the vehicle is in 2WD mode
  3. Observe the 2WD mode indicator within the transfer case shift control switch.
Is the 2WD indicator flashing?		 - Go to Step 10  Go to Step 3 
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 voltage circuit and the front axle ground circuit at the front axle actuator.
Is the voltage reading within the specified values?		 11-13 V Go to Step 4  Go to Step 6 
4 
  1. Connect a DMM between the ignition 3 voltage circuit and the front axle control circuit at the front axle actuator.
  2. Observe the DMM, while using the scan tool in order to engage the front axle.
Does the DMM indicate battery voltage?		 - Go to Step 5  Go to Step 8 
5 
  1. Connect a fused jumper wire between the ignition 3 circuit and the front axle switch circuit.
  2. Observe the 2WD indicator inside the transfer case shift control switch.
Does the 2WD indicator flash?		 - Go to Step 16  Go to Step 9 
6  Measure the voltage between the ignition 3 voltage circuit and ground.
Is the voltage reading within the specified values?		 11-13 V Go to Step 14  Go to Step 7 
7  Test for an open fuse in the front ignition 3 voltage circuit. Refer to Circuit Protection - Fuses and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 18  Go to Step 15 
8  Test the front axle control circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 18  Go to Step 17 
9  Test the actuator switch signal circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 18  Go to Step 17 
10 
  1. Disconnect the front axle actuator.
  2. Observe the 2WD mode indicator within the transfer case shift control switch.
Is the 2WD indicator flashing?		 - Go to Step 11  Go to Step 13 
11  Test the front axle actuator signal circuit for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 18  Go to Step 12 
12
  1. Disconnect connector C1 and C2 at the module.
  2. With the front axle actuator disconnected test the front axle control circuit for a short to ground. Refer to Testing for Short to Ground .
Did you find and correct the condition?		 - Go to Step 18  Go to Step 17 
13  Inspect the front axle for a mechanical malfunction.
Did you find and correct the condition?		 - Go to Step 18  Go to Step 17 
14 Repair an open in the front axle actuator ground circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 18  -
15 Repair an open in the ignition 3 voltage circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 18  -
16 Replace the front axle switch/actuator. Refer to Electric Motor Actuator Replacement .
Did you complete the repair?		 - Go to Step 18  -
17 Replace the transfer case shift control module. Refer to Control Module References for replacement, setup, and programming.
Did you complete the repair?		 - Go to Step 18  -
18
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle to determine if the symptom has been corrected.
Is the symptom still present?		 - Go to Step 2  System OK
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