Upon inspection, it may be found that all active safety system functions including adaptive cruise control and lane keep assist (LKA) appear to work as designed, or it may be found that LKA or adaptive cruise control is inoperative. It may be noted that the LKA indicator in the DIC (driver information center) does not come on. There may be no DTCs stored for the FVCM systems.
Verify that the B174W FVCM is communicating on the low-speed bus and if the vehicle is equipped with UGN. Also, verify that the K124 ASCM is communicating on the low-speed bus.
To confirm communication, connect the data bus diagnostic tool to the vehicle. Select the “detected state” tab and select “DLC terminal 1”. Look through the list of communicating modules and ensure that the B174W and K124 are both on the list.
If it is found that the K124 ASCM is not communicating at low speed (with UGN), inspect circuit 5060 for an opening in the harness near JX300. If an open is found, repair the circuit. If it is found that the B174W FVCM is not communicating at low speed, inspect X203 at the base of the A-pillar for bent, loose or backed-out terminals.
