Initial Inspection and Diagnostic Overview
How to Troubleshoot the Collision Mitigation Brake System (CMBS)
CMBS Indicator
If the system is OK, the CMBS indicator goes off 2 seconds after turning the ignition switch to ON (II). The CMBS indicator comes on when the ACC unit detects a problem in the system.
NOTE:
- The ACC indicator indicates problems related with the ACC system and the CMBS.
- The CMBS indicator only indicates its system problems.
- The CMBS works with related systems such as the VSA system. If these related systems have a problem, the CMBS does not operate. In this case, the CMBS indicator and the related system indicator come on.
When a problem is detected by the self-diagnostic function, the CMBS stops operating, turns on the CMBS indicator, indicates the problem on the MID, and stores the DTC.
CMBS OFF Switch
Press and hold the CMBS OFF switch for at least a second to turn the CMBS off and on.
CMBS Indication
- If the system is OK, the CMBS indicator comes on for 5 seconds after turning the ignition switch ON (II) with the CMBS OFF switch on.
- When the system is activated, the word "BRAKE" is indicated on the MID and the warning buzzer sounds.
- First stage, BRAKE indicator and buzzer
- Second stage, BRAKE indicator, buzzer, light braking, and light seat belt tension
- Third stage, BRAKE indicator, buzzer, strong braking, and strong seat belt tension
- If the system stops operating because of a problem, the MID indicates the problem.
ACC Unit
The ACC unit controls the brake and warning when the system recognizes the danger of a collision.
The ACC unit has a self-diagnostic function. If the system detects a problem, it stops the CMBS, and turns on the CMBS indicator.
CMBS Initial Check
The ACC unit turns on the CMBS indicator if the CMBS initial check is not completed.
NOTE: For proper CMBS operation, if the ACC unit is replaced, do the CMBS initial check incomplete troubleshooting (DTC 100) 100.
Millimeter Wave Radar
The millimeter wave radar recognizes the position of the vehicle running ahead and detects the two vehicles speed differential.
The ACC unit receives this information from the millimeter wave radar.
The millimeter wave radar also has an error detect function, and sends a signal to the ACC unit if an error is detected.
How to Troubleshoot DTCs
Check and clear the DTCs with the HDS.
NOTE: When both the ACC and CMBS indicators come on, do the ACC system troubleshooting first (except DTC 100).
Before troubleshooting, check and note these items:
- Ask the client about the conditions when the problem occurred, and try to reproduce the same conditions for troubleshooting.
- If the symptom does not appear and the CMBS indicator does not come on during the test-drive, but troubleshooting is done based on the DTC, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting.
- After the troubleshooting or repairs are done, clear the DTCs, and test-drive the vehicle under the same conditions as when the DTC was originally.
- The ACC system and the CMBS may sometimes stop working because of the environment (weather, road conditions, driving conditions, etc.). A DTC may be stored in these cases.
DTCs may be stored even when the system is normal:
ACC indicator does not come on, CMBS indicator comes on
DTC 88: Millimeter wave radar out of detection condition
The millimeter wave radar overheats, the power supply voltage for the millimeter wave radar is low, or there is a communication error between the ACC unit and the millimeter wave radar.
DTC 95: Power supply voltage too high
DTC 96: Power supply voltage too low
DTC 97: CMBS offset cancel time-out
Extensive driving on a rough road or the ignition switch is turned to ON (II)/LOCK (0).
DTC 102: CMBS parking brake incomplete releasing
Parking brake not fully released, or driving with the parking brake stuck.
How to Retrieve DTCs
NOTE: Make sure the battery is fully charged before you begin.
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) under the left side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the ACC unit. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.
4. Use the HDS to check for ACC DTCs.
5. Read and record the DTC.
6. Turn the ignition switch to LOCK (0).
7. Disconnect the HDS from the DLC.
8. Do the troubleshooting procedure for the DTC.
How to Clear DTCs
NOTE: Make sure the battery is fully charged before you begin.
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) under the left side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the ACC unit. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.
4. In the DRIVING SUPPORT MENU of the HDS, select ACC, then DTCs choose the clear DTCs icon, and follow the prompts.
5. Turn the ignition switch to LOCK (0).
6. Disconnect the HDS from the DLC.