Circuit/System Testing
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF/vehicle OFF, and all vehicle systems OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON/vehicle in Service Mode.
- Test for less than 4 V between each of the signal circuits listed below and ground:
- Terminal 1
- Terminal 2
- If 4 V or greater
- Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON/vehicle in Service Mode.
- Test for less than 1 V between the signal circuits and ground.
- If greater than 1 V, repair the short to voltage on the circuit.
- If less then 1 V, replace the A11 Radio.
- Go to next step: If less than 4 V
- Ignition OFF/vehicle OFF.
- Test for infinite resistance between each of the signal circuits listed below and ground:
- Terminal 1
- Terminal 2
- If less than infinite resistance
Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Disconnect the X1 harness connector at the A11 Radio.
- Test for less than 2 Ω in each of the signal circuits listed below end to end:
- K73 Telematics Communication Interface Control Module Terminal 1 X2
- K73 Telematics Communication Interface Control Module Terminal 2 X2
- If 2 Ω or greater
Repair the open/high resistance on the circuit.
- Go to next step: If less than 2 Ω
- Replace the K73 Telematics Communication Interface Control Module.
- Verify that the Connecting to OnStar® message is heard clearly through the audio system when the OnStar® blue button is pressed.
- If audio is not heard clearly
Replace the A11 Radio.
- Go to next step: If audio is heard clearly
- If audio is not heard clearly
- All OK.