Circuit/System Testing

WARNING: This page is about a different car, the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, and 2018 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the harness connector at the A16 transfer case motor, also known as the transfer case range actuator.
Ignition ON, engine OFF.
Test for 1.0 - 2.5 V between the transfer case motor counter-clockwise control circuit terminal D and a good ground, such as the ground terminal of the EL-49742 harness, black terminal.
NOTE:
- When test probing harness terminals, it is imperative to use the proper test probe from the most current version of the J-35616 GM-Approved Terminal Test Kit. Use of an improper test probe may deform the terminal, resulting in intermittent open conditions.
- Testing for steps 3 - 5 is performed on the A16 transfer case motor harness connector using the PU probes J 35616-4A.
- If less than the specified range
1. Ignition OFF, disconnect the X3 harness connector at the K69 transfer case control module.
2. Test for less than 10 Ω in the transfer case motor counter-clockwise control circuit end to end.
  - If 10 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 10 Ω
3. Test for infinite resistance between transfer case motor counter-clockwise control circuit terminal D and a good ground.
  - If less than infinite resistance, repair the short to ground in the circuit.
  - If infinite resistance
4. Test for greater than 10 Ω between the transfer case motor counter-clockwise control circuit terminal D and all other terminals of the A16 transfer case motor harness connector.
  - If 10 Ω or less, repair the shorted together condition in the affected circuits.
  - If greater than 10 Ω, replace the K69 transfer case control module and perform the Range Actuator Learn procedure.
- If greater than the specified range
1. Ignition OFF, disconnect the X3 harness connector at the K69 transfer case control module. Ignition ON, Engine OFF.
2. Test for less than 1 V between the transfer case motor counter-clockwise control circuit terminal D and a good ground.
  - If 1 V or greater, repair the short to voltage in the circuit.
  - If less than 1 V
3. Test for greater than 10 Ω between the transfer case motor counter-clockwise control circuit, terminal D and all other terminals of the A16 transfer case motor harness connector.
  - If 10 Ω or less, repair the shorted together condition in the affected circuits.
  - If greater than 10 Ω, replace the K69 transfer case control module and perform the Range Actuator Learn procedure.
- Go to next step: If within the specified range
Transfer case motor counter-clockwise control circuit and K69 transfer case control module OK.
Test for 3.0 - 4.5 V between the transfer case motor clockwise control circuit terminal A, and a good ground, such as the ground terminal of the EL-49742 harness, black terminal.
- If less than the specified range
1. Ignition OFF, disconnect the X3 harness connector at the K69 transfer case control module.
2. Test for less than 10 Ω in the transfer case motor clockwise control circuit end to end.
  - If 10 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 10 Ω
3. Test for infinite resistance between transfer case motor clockwise control circuit terminal A and a good ground.
  - If less than infinite resistance, repair the short to ground in the circuit.
  - If infinite resistance
4. Test for greater than 10 Ω between the transfer case motor clockwise control circuit terminal A and all other terminals of the A16 transfer case motor harness connector.
  - If 10 Ω or less, repair the shorted together condition in the affected circuits.
  - If greater than 10, replace the K69 transfer case control module and perform the Range Actuator Learn procedure.
    Refer to Transfer Case Control Module Replacement and Transfer Case High/Low Clutch Reset .
- If greater than the specified range
1. Ignition OFF, disconnect the X3 harness connector at the K69 transfer case control module. Ignition ON, Engine OFF.
2. Test for less than 1 V between the transfer case motor clockwise control circuit terminal A and a good ground.
  - If 1 V or greater, repair the short to voltage in the circuit.
  - If less than 1 V
3. Test for greater than 10 Ω between the transfer case motor clockwise control circuit, terminal A and all other terminals of the A16 transfer case motor harness connector.
  - If 10 Ω or less, repair the shorted together condition in the affected circuits.
  - If greater than 10 Ω, replace the K69 transfer case control module and perform the Range Actuator Learn procedure.
    Refer to Transfer Case Control Module Replacement and Transfer Case High/Low Clutch Reset .
- Go to next step: If within the specified range
Transfer case motor counter-clockwise control circuit, transfer case motor clockwise control circuit and K69 transfer case control module OK.