Collision Mitigation Brake System (Cmbs): Other Acura RL II facelift

CMBS Indicator

If the system is OK, the CMBS indicator goes off 2 seconds after turning the ignition switch ON (II). The CMBS indicator comes on when the adaptive cruise control (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.

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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

1. 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.
2. 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
3. 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 or the VSA modulator-control unit is replaced, do DTC 100: CMBS INITIAL CHECK INCOMPLETE .

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 Clear DTCs

Note. You cannot clear the DTCs manually.

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1. With the ignition switch is 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 (see «DLC CIRCUIT TROUBLESHOOTING»(ref-348508-S35625078472009112400000) ).
4. Clear the DTC(s) by following the screen prompts on the HDS. NOTE: See the HDS Help menu for specific instructions. Some DTCs cannot be cleared until the radar aiming is complete.

Main Functions Of CMBS

1. When a collision is about to happen and the relative speed (the speed difference from the object ahead) is greater than 9 mph (15 km/h), the system provides warnings (audible and visual) and brake control.
2. When approaching a object ahead and the distance to the vehicle is very close, the system provides the collision warning (1st stage) by MID indication and buzzer sounding.
3. 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.
4. 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 the following 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 and the predictable course calculated by the driving conditions (wheel speed and yaw rate).

Warning Function

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 might activate (warn the driver, apply the brakes) when it detects or encounters these situations

1. Metallic projections on the road
2. Metallic manhole and drain covers
3. Signs and guardrails ahead
4. Low overpasses and narrow gates
5. Approaching vehicles that are turning left or right
6. Passing slower vehicles ahead

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

1. Low-speed, heavy traffic (such as in a traffic jam)
2. Being cut-off by a slower vehicle
3. Approaching a vehicle stopped at an angle
4. Driving on curves
5. Approaching a bicycle or moped
6. Dirt or snow stuck on the front radar cover
7. Heavy rain or snow

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

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WIRE TEST CONDITION REFERENCE TABLE

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CMBS Indicator Does Not Go Off

1. Turn the ignition switch to ON (II).
2. Press and hold the CMBS OFF switch for a second or more to turn off the system.
3. Watch the CMBS indicator. Does the CMBS indicator go off? YES - The system is OK at this time. NO - Go to step 4 .
4. Turn the ignition switch to LOCK (0).
5. Connect the HDS to the data link connector.
6. Clear the DTCs with the HDS.
7. Turn the ignition switch to ON (II).
8. Check for the adaptive cruise control (ACC) system, VSA, and PCM DTCs with the HDS. Are any DTCs indicated? YES - Troubleshoot the indicated DTC(s). NO - Go to step 9 .
9. Start the engine, and wait at least 2 seconds.
10. Watch the CMBS indicator. Does the CMBS indicator stay off? YES - The system is OK at this time. NO - Go to step 11 .
11. Stop the engine.
12. Check for ACC system DTCs with the HDS. Are any DTCs indicated? YES - Troubleshoot the indicated DTC(s). NO - Test the CMBS OFF switch (see «CMBS OFF SWITCH TEST/REPLACEMENT»(ref-348611-S38000232002009112400000) ). If the switch is OK, do the gauge control module self-diagnostic function (see «SELF-DIAGNOSTIC FUNCTION»(ref-348531-S03408269372009112400000) ).

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1. Remove the instrument fascia (see «INSTRUMENT FASCIA REMOVAL/INSTALLATION»(ref-348558-S12901056102009112400000) ).
2. Remove the screws and the multi-switch (A).
3. Check for continuity between the terminals in each CMBS OFF switch position according to the table below.
4. If the continuity is not as specified, replace the switch.