Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the S126 Drive Mode Select Switch. It may take up to 2 min for all vehicle systems to power down.
Test for less than 5 Ω between the ground circuit terminal 10 and ground.
- If 5 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 5 Ω
Ignition ON.
Verify the scan tool Hill Descent Control Switch parameter is Inactive.
- If not Inactive
1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit terminal 10 X1 and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the K9 Body Control Module.
- If Inactive
Install a 3 A fused jumper wire between the signal circuit terminal 11 and the ground circuit terminal 10.
Verify the scan tool Hill Descent Control Switch parameter is Active.
- If not Active
1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V
3. Test for less than 2 Ω in the signal circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K9 Body Control Module.
- If Active
Test or replace the S126 Drive Mode Select Switch.