Some 300,000 school buses, coaches, trucks and tractors are being voluntarily recalled to replace a Bendix ABS controller that could cause brake loss for short periods at low speeds. The EC-17 electronic control unit (ECU) was used on all Bendix air-brake ABS installed as original equipment in power units between February 1998 and this past August.
Some school-bus drivers have reported up to 4-sec. lags in brake applications at speeds under 18 mph. The problem is caused by rotating wheel end components rubbing through the insulation on ABS wheel sensor wires. In contact with bare wire, the rotating component creates electronic noise that the controller interprets as impending wheel lockup.
A smaller number of malfunctions have also been traced to tone rings rubbing against wheel sensors, creating similar electronic noise. Although there have been a small number of brake-loss incidents, Bendix says there have been no reports of any accidents or injuries related to the controller problem.
Bendix and the vehicle manufacturers notified the National Highway Traffic Safety Administration about the problem and outlined their voluntary recall plans on August 22.
Using a three-phase recall, Bendix is replacing the EC-17 with either an EC-17 2.3 controller or its next generation EC-30 ECU. The ECU's are built by two suppliers.
Under the first phase, begun September 15, Bendix replaced affected controllers on school bus models with the most reported incidents. It will begin ECU replacements for all other school buses and coaches on October 15, followed by trucks in sensitive vocations such as emergency service on November 15.
All other truck models with reported ABS incidents will be recalled starting January 1, 2001, and EC-17 controllers on the remaining trucks will be replaced starting February 1. There have been no reported incidents involving tractors, according to Bendix, and they will be recalled for ECU replacement beginning April 1, 2001.
Vehicles with the EC-17 controller do not have to be pulled from service while waiting for the replacement ECU, according to Bendix. Instead, the company suggests that for the short term, fleets check sensor wires for evidence of chaffing and secure those wires with tie-downs. For full technical details, as well as complete information on the recall, go to www.bendix.com/absrecall.