How to Troubleshoot the Adaptive Cruise Control (ACC)
ACC Indicator (Amber)
When the ACC system detects a problem while operating, the ACC system stops working, then the ACC indicator and the brake system indicator (amber) stay on.

NOTE: The ACC system communicates with the PCM, the VSA system, and the gauge control module via F-CAN. If a connected unit malfunctions, the ACC system will not work. In this case, both the ACC indicator and the connected unit indicator come on and stay on (except the gauge control module).

Multi-Information Display (MID) Indication
When the ACC system is OK, the ACC indicates its status on the multi-information display (MID) when the MAIN switch is ON.
Self-Diagnostic Function
The ACC system has a self-diagnostic function. If the self-diagnostic function detects a malfunction, the ACC system stops working, turns on the ACC indicator (amber), and stores DTCs.
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 ACC 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 ACC 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 ACC 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 ACC automatically resumes operation.

Multipurpose Camera Unit
The multipurpose camera unit uses inputs from the millimeter wave radar to maintain a constant distance between your vehicle and the vehicle directly ahead by accelerating and braking as needed.
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 ACC indicator blinks.
Millimeter Wave Radar
The millimeter wave radar measures the distance between your vehicle and the vehicle directly ahead to calculate and adjust speed to maintain the set distance between your vehicle and the vehicle ahead.

The multipurpose camera unit receives this information from the millimeter wave radar.

The millimeter wave radar also has an error detection function which 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.
CAN Communication
The multipurpose camera unit communicates on the F-CAN, and it communicates with other units via the F-CAN (gauge control module, steering angle sensor, PCM, and VSA modulator-control unit).

If the multipurpose camera unit detects a communication error or a malfunction in another connected unit, the ACC system will not operate even though it is OK. In this case, both the ACC indicator (amber) and the related unit indicator will come on and stay on.
How to Troubleshoot DTCs
Check for DTCs with the HDS. Make a copy of the freeze data, then clear the DTC.

Before troubleshooting, check and note these items:
Ask the customer about the conditions when the problem occurred, and try to reproduce the same conditions for troubleshooting.
If the symptom does not appear and the ACC indicator does not come on during the test-drive of the vehicle, but if troubleshooting is done based on a DTC, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting.
After 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 ACC indicator does not come on.
The ACC system sometimes stops working because of certain environmental conditions (weather, road conditions, driving conditions, etc.).
DTC may be stored even when the system is OK:
NOTE: The ACC indicator does not come on when DTC B2A00-F8: ACC Brake Control Temporarily Prohibited is stored.
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 poor connections or loose 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 ACC DTCs.

6.
Read and record the DTC.

Freeze data records the ACC 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.
How to Read History of the System Auto Stop Control Code
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 DATA LIST.

6.
Read and record the auto stop control code in the DATA LIST.

NOTE:
ACC system auto stop control history is recorded from 1. When automatic cancellation takes place 11 times or more, the past 10 records are held. In this case, history 10 is the latest record and the 10 latest records are held. When 0, no record is held.
When DTCs are cleared by the HDS, ACC system auto stop control history is cleared as well.
Some of the following ACC system auto stop control codes may not be used for specific model specifications.
ACC System Auto Stop Control Codes
Code
ACC system auto stops operating
ACC Indicator
Also check for
82
Adaptive cruise control (ACC) brake control temporarily prohibited by Electric Parking Brake
?
The ACC brake works continuously, or ACC brake control is temporarily prohibited by a communication line error detected between the multipurpose camera unit and electric parking brake control unit.
83
Radar detection unstable
?
Driving behind a target vehicle that caused unstable reception.
84
Target vehicle comes closer than the radar detecting limits
?
The target vehicle brakes suddenly, etc.
85
Extensive driving on a rough or winding road
?
Extensive driving on a rough or winding road.
86
Abnormal tire pressure
?
Abnormal tire pressure, flat tire.
87
Adaptive cruise control (ACC) brake control temporarily prohibited by VSA
?
The ACC brake works continuously, or ACC brake control is temporarily prohibited by a communication line error detected between the multipurpose camera unit and VSA modulator-control unit.
88*
Radar temporary problem (temperature, voltage, etc)
?
The millimeter wave radar temperature is too high, the millimeter wave radar supply voltage is too low, or out of detection condition.
89
Front wheel spin
?
Front wheel spin when the vehicle is driving.
91
Vehicle skidded, spun out, or abrupt steering wheel movements
?
Vehicle skidded, spun out, or abrupt steering wheel movements.
93
Front tire problem
?
Different diameter tires, flat tire, or large air pressure differential.
94
Rear tire problem
?
Different diameter tires, flat tire, or large air pressure differential.
95*
Power supply voltage too high
?
Battery voltage
96*
Power supply voltage too low
?
Battery voltage
97*
Extensive driving on a rough or winding road. (CMBS/FCW)
?
Extensive driving on a rough road or turn the vehicle to the OFF (LOCK) mode when the vehicle is driving.
98
Multipurpose camera unit temperature too high
?
Parked under the blazing sun for a certain time.
99
Acceleration/deceleration abnormality
?
Detect the vehicle acceleration/deceleration abnormality.
101
Rear wheel locked
?
Driving with the parking brake applied, or the parking brake stuck.
108
Adaptive cruise control (ACC) brake control temporarily prohibited by ESB
?
The ACC brake works continuously, or ACC brake control is temporarily prohibited by a communication line error detected between the multipurpose camera unit and electric servo brake control unit.
127
i-DCD cannot receive traction request
?
After the DCT (the built-in motor type) shifted during the acceleration. (especially low speed).
140
Yaw rate sensor temporarily error (low voltage, etc.)
?
12 Volt battery deterioration.
*: While the code is detected, the CMBS operation stops temporarily.

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

8.
Disconnect the HDS from the DLC.