What is the CMBS warning light on my Acura?
The CMBS warning light indicates a fault or temporary inoperability in Acura's Collision Mitigation Braking System. If the light is on, the system may be unavailable or not functioning correctly, and you should have the vehicle inspected by an Acura dealer. The light can also come on if sensors are dirty, blocked, or misaligned due to weather or minor impacts.
CMBS is designed to help reduce the severity of frontal collisions by monitoring traffic ahead with a forward camera and radar sensor, and it may provide warnings or automatically apply brakes if a risk is detected. In Acura vehicles, CMBS is part of a broader safety suite that often works alongside Adaptive Cruise Control and Forward Collision Warning. The warning light signals that something in that system is not operating correctly, or that calibration or service is required.
How CMBS works in Acura vehicles
CMBS uses a forward-facing camera near the windshield and radar sensors behind the front grille to monitor traffic ahead. If the system detects a potential collision, it may issue warnings and, if necessary, apply braking to mitigate or avoid impact. It works with other safety features like Adaptive Cruise Control (ACC) and Lane Keeping Assist to provide a coordinated safety net, but it is not a substitute for attentive driving. Conditions such as weather, road layout, and sensor quality can affect performance.
Common reasons the CMBS warning light comes on
The following are common situations that can trigger the CMBS warning light on Acura models. If you see the light, it may indicate a fault or a temporary condition that needs attention.
- Sensor obstruction: Dirt, snow, ice, or water on the forward-facing camera or radar sensor can trigger a fault condition.
- Sensor or system misalignment: Impact damage, windshield replacement, or front-end work can require recalibration of the cameras and radar sensors.
- Weather or environmental conditions: Extremely cold or hot weather and moisture can temporarily affect sensor performance.
- Software or hardware fault: A fault in the CMBS control module or related software may cause the warning light to illuminate.
- Calibration need after maintenance: After windshield replacement or bumper repairs, the sensors often need official calibration to restore proper function.
If the CMBS warning light appears, it does not necessarily mean an imminent collision is guaranteed, but it does mean the system may be disabled or unreliable until checked and corrected by a professional.
What to do if the CMBS warning light appears
Follow these steps to address a CMBS warning light. The goal is to ensure the system is safe and accurate while you continue to drive.
- Drive with extra caution: Maintain a safe following distance and avoid relying on CMBS for braking or collision avoidance.
- Look for obvious causes: Check the forward-facing camera area behind the windshield and the front grille area for blocks, dirt, snow, or ice. If you can do so safely, clean the camera lens and wipe away obstructions.
- Check for messages on the instrument panel: Some Acura models display messages such as “CMBS unavailable” or “See Owner’s Manual” when the system is not operable.
- Avoid contamination to sensors: Ensure there is no aftermarket film, accessories, or excessive tint that could affect the camera’s view, and note any recent windshield or bumper work.
- Schedule service promptly: If the light remains on after cleaning or if you notice abnormal braking behavior, arrange a diagnostic with an Acura dealer or a qualified shop. Calibration or replacement of sensors may be required.
Persistent CMBS warnings should be treated as a system issue that requires professional inspection. A dealer can diagnose sensor faults, perform recalibration, update software, or replace faulty components as needed.
What to expect at the service visit
During a service visit, technicians will typically inspect the forward camera, radar sensor, wiring, and control module. They may:
- Inspect and clean both the camera and radar sensors.
- Check for any misalignment or damage from recent work or a collision.
- Run diagnostic tests to pinpoint fault codes and perform necessary calibrations or software updates.
- Recommend sensor replacement if a hardware fault is detected.
After service, the CMBS warning light should illuminate briefly during a normal startup as the system reinitializes, then should remain off if no faults are present. If the light reappears, further diagnostic work may be required.
Summary
The CMBS warning light on your Acura signals that the Collision Mitigation Braking System may be malfunctioning or temporarily unavailable. Common causes include sensor dirt or obstruction, misalignment after maintenance or an impact, or a software/hardware fault. If the light comes on, drive cautiously, inspect the sensor areas, and seek professional diagnosis and calibration from an Acura dealer if the light does not go away or if you notice abnormal braking behavior. Regular maintenance and post-repair calibration can help preserve CMBS performance and overall safety.
What is a CMBS problem?
Key CMBS Issues:
False Braking Alerts: The system may trigger sudden stops without obstacles, increasing the risk of rear-end collisions. Sensor Malfunctions: The radar sensor (located in the front grille) or camera system may misinterpret objects, leading to false alarms or failure to detect real hazards.
What is CMBS in Acura?
Including if the speed difference between your vehicle. And another vehicle pedestrian or moving bicycle is about 5 km. Hour or more with a chance of collision.
Why is my CMBS light on?
The CMBS (Collision Mitigation Braking System) light indicates a fault in the forward-facing radar or camera sensors. Dirt, misalignment, or sensor damage can trigger the warning. Start by cleaning the radar sensor behind the grille and the windshield camera.
How to fix collision mitigation system problem?
To reset the collision mitigation system, start by turning off the engine and disconnecting the battery for about 10 minutes to reboot the ECU. Inspect front sensors and cameras for dirt or obstruction, cleaning them gently if needed. After reconnecting the battery, start the vehicle and check for warning lights.
