Acura MDX, RLX Recall Issued Over Automatic Braking Problem

Honda has recalled nearly 20,000 Acura vehicles after receiving reports that two drivers experienced problems where the advanced braking system activated unexpectedly, causing at least one accident. 

The Acura recall (PDF) was announced by the National Highway Traffic Safety Administration (NHTSA) on June 9, due to issues with the Forward Collision Avoidance: Crash Imminent Braking system, which may incorrectly interpreted roadside metal fences and guardrails as obstacles.

In both incident reports received by the auto maker, Acura vehicles had the internal braking system applied to the driver’s surprise, resulting in at least one rear end collision.

The recalled Acura vehicles are equipped with a Collision Mitigation Braking System (CMBS), which is designed to use millimeter wave radar to scan traffic conditions ahead of the vehicle. When the software recognizes a vehicle or objects ahead and determines there is a collision hazard, the CMBS software applies emergency braking to help reduce the severity of a collision if the driver fails to apply the brakes on their own.

The two warranty claims indicate the CMBS may incorrectly determine a potential forward collision if a vehicle is detected ahead traveling near a metallic structure, such as a metal fence or guardrail. The first warranty claim detailing the CMBS failure was reported on November 26, 2013, indicating the system applied the brakes without any obstructions, resulting in a rear end collision.

Honda attempted to recreate the situation and obtain the same result from the CMBS in 94 separate driving tests, but failed. The second warranty claim was reported on June 27, 2014, alleging the CMBS activated without any obstacles ahead of the vehicle. After a continued investigation, Honda determined the failure was the result of “short-distance combining process” of the CMBS’s logic causing the software to incorrectly recognize obstacle hazards when a vehicle accelerates by the sensors, while near a metal structure.

The recall impacts model year 2014 to 2015 Acura MDX 2WD models manufactured from May 6, 2013 through February 2, 2015, model year 2014 to 2015 Acura MDX AWD manufactured from April 23, 2013 through January 31, 2015, model year 2014 to 2015 Acura RLX manufactured from August 2, 2012 through October 22, 2014, and model year 2014 Acura RLX Hybrid models manufactured from April 15, 2013 to March 17, 2014.

Honda announced it will begin notifying customers by mail in June 2015. Customers will be instructed to schedule an appointment at a dealer where the software will be updated in all recalled vehicles free of charge.

Honda stated in the recall notice that customers may manually turn off the CMBS in their vehicle at their discretion until the repair is made. Owners with further questions may contact Acura at 1-800-382-2238 and reference the recall numbers JQ4, JQ5, and JQ6 or visit them online at recalls.acura.com