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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 616 (Drive Axle - Limited-Slip Differential) >> Diagnostic Information and Procedures >> All-Wheel Drive (AWD) Disabled Indicator Always On >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. 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. 3:  This step tests the ignition 1 voltage circuit for proper voltage.
  2. 4:  This step tests the ground circuit for an open.
  3. 5:  This step tests the axle actuator control circuit duty cycle.
  4. 6:  This step tests the axle actuator control circuit for an open or short.
All-Wheel Drive (AWD) Disabled Indicator Always On

Step Action Value(s) Yes No
Schematic Reference:  Differential Lock Schematics  
1 Did you perform the Diagnostic System Check - Rear Axle Controls? - Go to Step 2  Go to Diagnostic System Check - Locking/Limited Slip Rear Axle 
2 Verify the fault is present.
Does the system operate normally?		 - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 
  1. Disconnect the differential clutch pump actuator check valve.
  2. Turn ON the ignition, with the engine OFF.
  3. Using a DMM, test the ignition 1 voltage circuit for proper voltage.
Does the voltage measure within the specified value?		 9-14 V Go to Step 4  Go to Step 7 
4 
  1. Connect a test lamp between the ignition 1 voltage circuit and the ground circuit at the differential clutch pump actuator check valve.
  2. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?		 - Go to Step 5  Go to Step 8 
5 
  1. Turn the ignition OFF.
  2. With the connector connected, connect a DMM in parallel to the control circuit. Set the DMM to read duty cycle.
    3. IMPORTANT: The differential clutch pump actuator check valve duty cycle will initiate at 49-90 percent duty cycle for 3 seconds, then drop to 16-28 percent duty cycle. Every 30 seconds, the duty cycle will cycle up to 49-90 percent for 0.5 seconds, then back to 16-28 percent.
  3. Start the engine.
  4. Observe AWD Duty Cycle on the DMM from the time of engine start.
Is the duty cycle functioning as described?		 HI Range: 49-90%
LO Range: 16-28%		 Go to Step 9  Go to Step 6 
6  Test the axle actuator control circuit for the following conditions:
  • An open
  • A short to voltage
  • A short to ground

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
7 Locate and repair an open or short to ground in the ignition 1 voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 11  -
8 Locate and repair an open in the ground circuit. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 11  -
9 Replace the differential clutch pump actuator check valve. Refer to Differential Clutch Pump Check Valve Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the PCM or TCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls-3.4L or Module, Transmission Control - Replace in Automatic Transaxle 4T65-E for 3.6L.
Did you complete the replacement?		 - Go to Step 11  -
11
  1. Use the scan tool in order to clear the faults.
  2. Operate the vehicle within the Conditions for Running the All-Wheel Drive (AWD) Disable Fault, as specified in the supporting text.
Does the fault set?		 - Go to Step 3  Go to All-Wheel Drive (AWD) System Functional Inspection
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