Adaptive Cruise Control (ACC) Symptom Troubleshooting Index

NOTE: The ACC system is canceled when the VSA system is activated.

Symptom	Diagnostic procedure	Also check for
Vehicle speed can be set, but there is no ACC indication on the MID	Do the gauge control module self-diagnostic function .
ACC OFF is displayed on the MID unexpectedly	Check the ACC system auto stop control history - Refer to: ACC System Auto Stop Control History (2019 - 2021) or ACC System Auto Stop Control History (2022 - 2023) .
Vehicle speed cannot be set when the SET button is pressed between 25 mph (40 km/h) and 90 mph (145 km/h)	Test the ACC combination switch . Test the brake pedal position switch .	An open in the wire A short in the wire The system is in service mode.
Vehicle does not decelerate or accelerate accordingly when the SET- or RES+ button is pressed	Test the ACC combination switch .	An open in the wire
Set speed does not cancel when the brake pedal is pressed	Test the brake pedal position switch .	An open in the wire
Set speed does not cancel when the MAIN switch is turned off	Test the ACC combination switch .	An open in the wire
Set distance cannot be adjusted with the distance switch	Test the ACC combination switch .
Vehicle speed can be set, but vehicle decelerates	Check for DTCs in the PGM-FI system with the HDS .
ACC indicator (on the MID) does not come on	Symptom troubleshooting - Refer to: Lane Keeping Assist System (LKAS) Symptom Troubleshooting - LKAS indicator (on the MID) does not come on .
ACC indicator (on the MID) does not go off	NOTE: If any of the CAN communication failure DTC is indicated in another system, troubleshoot the DTC first. Check for a open wire or shorted wire in the F-CAN circuit; Between the gauge control module and the CAN gateway (F-CAN D_H, F-CAN D_L) Between the millimeter wave radar and the CAN gateway (F-CAN E_H, F-CAN E_L) Check the millimeter wave radar power circuit (IG1_VSA(VST)) Check the millimeter wave radar unit ground circuit (GND) Do the gauge control module self-diagnostic function .	Refer to the following about the indicator operating condition; How to Troubleshoot - Refer to: How to Troubleshoot the Adaptive Cruise Control (ACC) (2022 2023) or How to Troubleshoot the Adaptive Cruise Control (ACC) (2019 - 2021) Refer to the followings about the circuit troubleshooting; Gauge control module connector for inputs and outputs Millimeter wave radar connector for inputs and outputs ACC circuit diagram - Refer to: Adaptive Cruise Control (ACC) Circuit Diagram (2022 - 2023) or Adaptive Cruise Control (ACC) Circuit Diagram (2019 - 2022) Fuse to components index Ground to components index
Senses a vehicle driving in another lane	Symptom troubleshooting - Refer to: Adaptive Cruise Control (ACC) Symptom Troubleshooting - Senses a vehicle driving in another lane .	Incorrect millimeter wave radar installation Wheel alignment
Does not sense the vehicle driving ahead	Symptom troubleshooting - Refer to: Adaptive Cruise Control (ACC) Symptom Troubleshooting - Does not sense the vehicle driving ahead .	Out of the performance limits Wheel alignment Undetectable environment
Intermittently senses the vehicle driving ahead	Symptom troubleshooting - Refer to: Adaptive Cruise Control (ACC) Symptom Troubleshooting - Intermittently senses the vehicle driving ahead .	Incorrect millimeter wave radar installation Wheel alignment Undetectable environment