Circuit/System Testing

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

NOTE:

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

Ignition OFF and all vehicle systems OFF, It may take up to 2 minutes for all vehicle systems to power down.
Disconnect the harness connector at the S126 Drive Mode Select switch.
Test for less than 5 Ω between the ground circuit terminal 2 of the harness connector and ground.
- If 5 Ω or greater
  Repair the open/high resistance in the circuit.
- If less than 5 Ω
Test for 266-294 Ω between the 5 V reference voltage circuit terminal 3 of the switch and signal circuit terminal 1 of the switch.
- If not within the specified range
  Replace the S126 Drive Mode Select switch.
- If within the specified range
Test for 1,414-1,562 Ω between the 5 V reference voltage circuit terminal 3 of the switch and the ground circuit terminal 2 of the switch.
- If not within the specified range
  Replace the S126 Drive Mode Select switch.
- If within the specified range
With the S126 Drive Mode Select switch button depressed, test for 486-538 Ω between the 5 V reference voltage circuit terminal 3 of the switch and the ground circuit terminal 2 of the switch.
- If not within the specified range
  Replace the S126 Drive Mode Select switch.
- If within the specified range
Disconnect the X2 harness connector at the engine control module (ECM).
Test for less than 2 Ω in the 5 V reference voltage circuit end to end.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- If less than 2 Ω
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 K20 Engine Control Module.