LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 953 (Transfer Case - NVG 261-NP2) >> Diagnostic Information & Procedures >> Four-Wheel Drive Does Not Engage >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. 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:  Tests for proper ignition 3 voltage to the front axle actuator.
  2. 3:  Tests for proper ground at the front axle actuator.
  3. 4:  Tests for proper ground at the axle actuator control circuit through the transfer case switch.
  4. 5:  Tests the transfer case switch ground circuit for an open.
  5. 6:  Tests the transfer case switch for proper operation.
Four-Wheel Drive Does Not Engage

Step Action Values Yes No
Schematic Reference: Transfer Case Control Schematics 
1 Did you perform a Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Turn OFF the ignition.
  2. Disconnect the front axle actuator.
  3. Ensure the 4-wheel drive (4WD) control lever is in the 4WD position.
  4. Turn ON the ignition with the engine OFF.
  5. With a DMM, test the ignition 3 voltage circuit for proper voltage.
Does the voltage measure within the specified value?		 9-14 V Go to Step 3  Go to Step 7 
3 
  1. Disconnect the front axle actuator.
  2. Turn ON the ignition, with the engine OFF.
  3. With a DMM, measure the voltage between the ignition 3 voltage circuit and the ground circuit at the front axle actuator.
Does the voltage measure within the specified value?		 9-14 V Go to Step 4  Go to Step 8 
4 
  1. Turn ON the ignition, with the engine OFF.
  2. Shift the transfer case into 4HI.
  3. Connect a test lamp between the ignition 3 voltage circuit and the axle actuator control circuit, at the front axle actuator.
Does the test lamp illuminate?		 - Go to Step 11  Go to Step 5 
5 
  1. Disconnect the transfer case switch.
  2. Connect a test lamp from the ignition 3 voltage circuit to the transfer case switch ground circuit
Does the test lamp illuminate?		 - Go to Step 6  Go to Step 9 
6  With the control lever in the 4WD position, test for continuity across the transfer case switch.
Is continuity present across the switch?		 - Go to Step 10  Go to Step 12 
7 Repair the open in the ignition 3 voltage circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 13  -
8 Repair the open in the ground circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 13  -
9 Repair the open in the transfer case switch ground circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 13  -
10 Repair the open in the axle actuator control circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 13  -
11 Replace the front axle actuator. Refer to Front Drive Axle Actuator Replacement .
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the transfer case switch. Refer to Transfer Case Gear Indicator Switch Replacement .
Did you complete the repair?		 - Go to Step 13  -
13 Operate the vehicle in order to determine if the symptom has been corrected.
Is the symptom still present?		 - Go to Step 2  System OK
scientia non olet · About LEMON Manuals