Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the X1 harness connector at the K164 Differential Control Module, ignition ON/Vehicle in Service Mode.
Test for less than 1 V between the K164 Differential Control Module connector terminals listed below and ground.
- Terminal 1
- Terminal 4
- If 1 V or greater
  Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for infinite resistance between K164 Differential Control Module connector terminals listed below and ground.
- Terminal 1
- Terminal 4
- If less than infinite resistance
  Repair the short to ground on the circuit.
- Go to next step: If Infinite resistance
Disconnect harness connector at the M135 Differential Lock Motor.
Test for less than 2 Ω between M135 Differential Lock Motor connector terminal 3 and K164 Differential Control Module connector terminal 1 end to end.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
Test for less than 2 Ω between M135 Differential Lock Motor connector terminal 2 and K164 Differential Control Module connector terminal 4 end to end.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
Test or replace the M135 Differential Lock Motor.
Operate the vehicle under the conditions for setting the DTC, the DTC should not set.
- If the DTC sets
  Replace the K164 Differential Control Module.
- Go to next step: If no DTC sets
A fault is not currently present and may be an intermittent condition.