Circuit/System Testing

WARNING: This page is about a different car, the 2021 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Ignition/vehicle OFF, disconnect the harness connector at B24LF Mobile Telephone Microphone Left Front, ignition ON/vehicle in service mode.
Test for 8-11 V between the signal circuit terminal 2 and ground.
- If less than 8 V
1. Test circuit 655 for a short to ground.
  - If a short to ground is found, repair the fault on the circuit.
  - Go to next step: If a short to ground is not found.
2. Test circuit 655 for an open/high resistance.
  - If an open/high resistance is found, repair the fault on the circuit.
  - Go to next step: If an open/high resistance is not found.
3. Replace the K73 Telematics Control Module.
- If greater than 11 V
1. Test circuit 655 for a short to voltage.
  - If a short to voltage is found, repair the fault on the circuit.
  - Go to next step: If a short to voltage is not found.
2. Replace the K73 Telematics Control Module.
- Go to next step: If between 8-11 V
Test for less than 1 V between the low reference circuit terminal 1 and ground.
- If greater than 1 V
1. Test circuit 654 for a short to voltage.
  - If a short to voltage is found, repair the fault on the circuit.
  - Go to next step: If a short to voltage is not found.
2. Replace the K73 Telematics Control Module.
- Go to next step: If less than 1 V
Test for greater than 8 V between the signal circuit terminal 2 and the low reference circuit terminal 1.
- If less than 8 V
1. Test circuit 654 for an open/high resistance in the circuit.
  - If an open/high resistance is found, repair the fault on the circuit.
  - Go to next step: If an open/high resistance is not found.
2. Replace the K73 Telematics Control Module.
- Go to next step: If greater than 8 V
Replace the appropriate B24LF Mobile Telephone Microphone Left Front.