Acura RL. Manual - part 398

TEST/REPLACEMENT ).

3. Do the gauge control module

self-diagnostic function (see
SELF-DIAGNOSTIC
FUNCTION ).

The buzzer does not sound

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING
(NO DTC INDICATION) ).

2. Do the gauge control module

self-diagnostic function (see
SELF-DIAGNOSTIC
FUNCTION ).

The buzzer does not sound
when the CMBS OFF switch is
operated

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING
(NO DTC INDICATION) ).

2. Do the gauge control module

self-diagnostic function (see
SELF-DIAGNOSTIC
FUNCTION ).

The MID does not indicate
with the CMBS operating

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING
(NO DTC INDICATION) ).

2. Do the gauge control module

self-diagnostic function (see
SELF-DIAGNOSTIC
FUNCTION ).

The CMBS system operates
frequently

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING

Driving condition, weather,
environmental influence

2007 Acura RL

2005-08 BRAKES Collision Mitigation Brake System (CMBS) - RL

Friday, June 05, 2009 2:59:19 PM

Page 9

SYSTEM DESCRIPTION

The collision mitigation brake system (CMBS), anticipates rear-end collisions and assists brake operation to
reduce the impact on occupants and vehicle damage. The system works in combination with the e-

(NO DTC INDICATION) ).

2. Check the millimeter wave

radar unit.

3. Check the front emblem for

warpage.

4. Check the wheel alignment.

The CMBS system operated
without danger of collision

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING
(NO DTC INDICATION) ).

2. Check the millimeter wave

radar unit.

3. Check the front emblem for

warpage.

4. Check the wheel alignment.

Driving condition, weather,
environmental influence

The CMBS system didn't
operate

1. Adaptive cruise control

(ACC) system
troubleshooting (No DTC
Indication) (see ADAPTIVE
CRUISE CONTROL (ACC)
SYSTEM
TROUBLESHOOTING
(NO DTC INDICATION) ).

2. Check the millimeter wave

radar unit.

3. Check the front emblem for

warpage.

4. Check the wheel alignment.



Driving conditions,
weather, environmental
influences



Undetectable environment

CMBS indicator does not
come on

Do the gauge control module self-
diagnostic function (see SELF-
DIAGNOSTIC FUNCTION )

CMBS indicator does not go
off

Symptom troubleshooting (see
CMBS INDICATOR DOES NOT
GO OFF )

HDS does not communicate
with the adaptive cruise
control (ACC) unit or the
vehicle

Troubleshoot the DLC circuit (see
DLC CIRCUIT
TROUBLESHOOTING )

2007 Acura RL

2005-08 BRAKES Collision Mitigation Brake System (CMBS) - RL

Friday, June 05, 2009 2:59:19 PM

Page 10

pretensioners, which retract the seat belts in anticipation of impact.

CMBS OPERATION



Warnings are both audible (warning buzzer) and visual (MID)



Evasive action support and collision-speed reduction by brake control

Fig. 6: CMBS Operation Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

MAIN FUNCTIONS OF CMBS



When a collision with a vehicle ahead is about to happen at a vehicle speed greater than 9 mph (15
km/h) and the relative speed (the speed difference from the vehicle ahead) is greater than 9 mph (15
km/h), the system provides warnings (audible and visual) and brake control.



When approaching a vehicle ahead and the distance to the vehicle ahead is very close, the system
provides the collision warning (1st stage) by the MID indication and buzzer sound.



When the closing distance continues to decrease and there is a high risk of collision, the system
applies light braking (2nd stage) with the 1st stage warning.



When the system judges that a collision is imminent, the system activates emergency brake control.

CMBS CONTROL

The CMBS is operated by the ACC unit. The CMBS has these functions:

Obstacle determination function

The system determines the potential for collision by the distance from the vehicle ahead and the relative
speed based on the millimeter wave radar unit and the predictable course calculated by the driving
conditions (wheel speed and yaw rate).

Warning function

2007 Acura RL

2005-08 BRAKES Collision Mitigation Brake System (CMBS) - RL

Friday, June 05, 2009 2:59:19 PM

Page 11

When there is a high risk of collision, the system sends warning directions to the gauge control module and
warns by both audible and visual means.

Brake control function

When there is a high risk of collision, the system sends brake directions to the VSA modulator-control unit
and controls braking action.

CMBS ACTIVATION CONDITIONS

The system can activate (warn the driver, apply the brakes) when it detects or encounters these situations:



Metallic projections on the road



Metallic manhole and drain covers



Signs and guardrails ahead



Low overpasses and narrow gates



Approaching vehicles that are turning left or right



Passing slower vehicles ahead

The system does not activate (no warning or intervention) when it detects or encounters these situations:



Low-speed, heavy traffic (such as in a traffic jam)



Being cut-off by a slower vehicle



Approaching a vehicle stopped at an angle



Driving on curves



Approaching a bicycle or moped



Dirt or snow stuck on the emblem



Heavy rain or snow

When the CMBS activates, it sounds and feels just like ABS activation.

2007 Acura RL

2005-08 BRAKES Collision Mitigation Brake System (CMBS) - RL

Friday, June 05, 2009 2:59:19 PM

Page 12

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