How to Troubleshoot the Collision Mitigation Braking System (CMBS)

CMBS Indicator (Amber)

When the CMBS detects a problem while operating, the CMBS stops working, then the CMBS indicator and the brake system indicator (amber) stay on.

NOTE:

	The ACC indicator indicates problems related with the ACC system and the CMBS.
	When there is trouble to influence only a CMBS function, the ACC indicator does not come on, and only a CMBS indicator comes on.
	The CMBS communicates with the PCM, the EPS control unit, the VSA system, the steering angle sensor, and the gauge control module via F-CAN. If a connected unit malfunctions, the CMBS will not work. In this case, both the CMBS indicator and the connected unit indicator come on and stay on (except for the gauge control module).

Self-Diagnostic Function

When a problem is detected by the self-diagnostic function, the CMBS stops working, turns on the CMBS indicator, indicates the problem on the MID, and stores the DTC.

Dirt or Dust Detective Function (RADAR OBSTRUCTED Indication)

If the message RADAR OBSTRUCTED appears on the MID, the millimeter wave radar or the radar cover has enough dirt so that the millimeter wave radar is obstructed. The ACC system stops working.

Clean any dirt or contamination on the millimeter wave radar or the radar cover. Once the millimeter wave radar is unobstructed, the MID turns off and the ACC system automatically turns back to ON.

Dirt or dust detective function (CLEAN FRONT WINDSHIELD Indication)

If the message CLEAN FRONT WINDSHIELD appears on the MID, the camera lens or the windshield has enough dirt so that the camera view is obstructed. The CMBS system stops working.

Clean any dirt or contamination on the camera lens or the windshield. Once the camera's view is unobstructed, the MID turns off and the CMBS system automatically turns back to ON.

System Protect Function (High temperature) (MULTIPURPOSE CAMERA HOT Indication)

If the message MULTIPURPOSE CAMERA HOT appears on the MID, the CMBS system stops working. The multipurpose camera unit temperature is too hot.

When the multipurpose camera temperature cools down to its proper operating temperature, the indicator on the MID turns off, and the CMBS automatically resumes operation.

Multipurpose Camera Unit

The multipurpose camera unit controls the brakes and the various driver warnings when the system recognizes the possibility of a collision.

The multipurpose camera unit has a self-diagnostic function. If the system detects a problem, it disables the CMBS, and turns on the CMBS indicator.

Multipurpose Camera Aiming Function

If the multipurpose camera unit is removed or replaced, you must do the multipurpose camera aiming procedure. If the aiming is incomplete, the CMBS indicator blinks.

Millimeter Wave Radar

The millimeter wave radar calculates the distance between the moving vehicle ahead and your vehicle, and detects the two vehicle's speed differential.
The multipurpose camera unit receives this information from the millimeter wave radar.
The millimeter wave radar also has an error detection function, and it sends a signal to the multipurpose camera unit if an error is detected.

Millimeter Wave Radar Aiming

If the millimeter wave radar is removed or replaced, you must do the millimeter wave radar aiming procedure, otherwise the ACC indicator (amber) comes on.

Head Up Warning Unit

When a warning signal is sent from the multipurpose camera unit to the gauge control module because the driver is approaching the vehicle ahead, the gauge control module drives the head up warning unit. The head up warning unit flashes to warn the driver about the vehicle ahead.

CMBS OFF Switch

Press and hold the CMBS OFF switch for at least 1 second to turn the CMBS off and on.

CMBS Indication

	When the CMBS system is OK, the CMBS indicator comes on for about 5 seconds then go off after turning the vehicle to the ON mode.
	When you set the CMBS to OFF, the multipurpose camera unit turns on the CMBS indicator.
	When the system is activated, the MID displays a warning indicator and a warning buzzer sounds.
	If the system stops working because of a problem, the MID indicates the problem.

How to Troubleshoot DTCs

Check and clear the DTCs with the HDS.

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 while test-driving, 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 set. Make sure the CMBS indicator does not come on.
	The ACC system and the CMBS may sometimes stop control because of the environment (weather, road conditions, driving conditions, etc.). A DTC may be stored in these cases.

There may be auto stop system control codes stored even when the system is OK:

NOTE: The ACC indicator will not come on, but the CMBS indicator comes on when the following codes are stored.

Code 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 multipurpose camera unit and the millimeter wave radar.

Code 95: Power Supply Voltage Too High

The power supply voltage for the multipurpose camera unit is 16.8 V or more.

Code 96: Power Supply Voltage Too Low

The power supply voltage for the multipurpose camera unit is 9.5 V or less.

Code 97: CMBS Offset Cancel Timeout

Extensive driving on a rough road or turning the vehicle to the OFF (LOCK) mode when the vehicle is driving.

Code 102: CMBS (CMS) Parking Brake Incomplete Releasing

The parking brake not fully released, or driving with the parking brake stuck.

Intermittent Failures

The term "intermittent failure" means a system may have had a failure, but it checks OK now. If you cannot reproduce the condition, check for loose connections and terminals. Also check ground and power connections related to the circuit that you are troubleshooting.

How to Retrieve DTCs

NOTE: Make sure the 12 volt battery is fully charged before you begin.

1.	Turn the vehicle to the OFF (LOCK) mode.

2.	Connect the HDS (Honda Diagnostic System) to the data link connector (DLC) (A) located under the driver’s side of the dashboard.

3.	Turn the vehicle to the ON mode.

4.	Make sure the HDS communicates with the vehicle and the multipurpose camera unit. If it does not communicate, go to the DLC circuit troubleshooting.

5.	Use the HDS to check for CMBS for DTCs.

Read and record the DTC.

	Freeze data indicates the CMBS conditions when the first system malfunction that activated the indicator was detected.
	The HDS can read the DTC, the freeze data, the current data, and other system data.

7.	Turn the vehicle to the OFF (LOCK) mode.

8.	Disconnect the HDS from the DLC.

9.	Do the troubleshooting procedure for the DTC.

How to Clear DTCs

NOTE: Make sure the 12 volt battery is fully charged before you begin.

1.	Turn the vehicle to the OFF (LOCK) mode.

2.	Connect the HDS (Honda Diagnostic System) to the data link connector (DLC) (A) located under the driver’s side of the dashboard.

3.	Turn the vehicle to the ON mode.

4.	Make sure the HDS communicates with the vehicle and the multipurpose camera unit. If it does not communicate, go to the DLC circuit troubleshooting.

5.	In the DRIVING SUPPORT MENU of the HDS, select Integrated Driver Support System, then DTCs choose the clear DTCs icon, and follow the prompts.

6.	Turn the vehicle to the OFF (LOCK) mode.

7.	Disconnect the HDS from the DLC.