Circuit/System Verification

WARNING: This page is about a different car, the 2020 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON.
Verify there are no DTCs set.
- If any DTC's are set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle
- Go to next step: If no DTC's are set
Drive the vehicle.
Verify the lane keep assist and forward collision alert systems are able to be turned on and off using their respective control switches, function properly, and there are no service messages displayed related to either system.
- If the lane keep assist and forward collision alert system is not operating properly
  Diagnose any faults in these systems prior to diagnosing the adaptive cruise control system. Refer to Symptoms - Driver Assistance Systems .
- Go to next step: If the lane keep assist and forward collision alert system are operating properly
Press and release the Adaptive Cruise Control Gap Switch.
Verify the adaptive cruise control gap setting on the P9 Driver Information Center Display changes between Far, Medium, and Near with each button press.
- If the gap setting does not change
  Refer to Circuit/System Testing.
- Go to next step: If the gap setting changes
Drive the vehicle.
Verify the adaptive cruise control system is able to be engaged and disengaged normally and all systems functions are operating as designed.
- If the adaptive cruise control system malfunction is identified
  Use the scan tool Adaptive Cruise Control Disable History Data parameters as described in Diagnostic Aids to identify the cause of the inhibit or disable condition and diagnose and repair as necessary.
- Go to next step: If the adaptive cruise control system is operating as designed
All OK. A fault is currently not present and may be an intermittent condition. Refer to Diagnostic Aids.