"Some of the common problems are the inability (of technicians) to use a volt-/ohmmeter, and basically the lack of knowledge of how ABS works," says Matt Williams, technical support manager for MeritorWABCO. "We all analyze warranty return parts, and the number one thing we see is 'no defect found.'" "This is not isolated to Bendix," he adds. For example, a sensor fault can be caused by wiring or issues at the wheel end, and not just the sensor or the ECU. "For example, if there's a sensor diagnostic trouble code, we'll see technicians who just automatically replace the sensor, then when that doesn't correct the issue, (they) replace the ECU, rather than follow a disciplined troubleshooting approach. "The biggest issue that we see with someone troubleshooting ABS systems is that the mechanics tend to automatically replace the component rather than performing a proper troubleshooting," says Tom Weed, staff engineer, ABS Engineering Group, Bendix Commercial Vehicle Systems. How long should it reasonably take for fleet maintenance technicians to master "new" technology? At what point should you expect your technicians to be able to properly troubleshoot and repair a system that has been mandated on heavy duty tractors since 1997, and trailers since 1989?Īccording to engineers at brake component suppliers MeritorWABCO and Bendix Commercial Vehicle Systems, heavy truck and trailer anti-lock brake systems (ABS) are still commonly misdiagnosed, even though they have been standard issue for nearly a decade.