| Brakes By Fred Andersky, Director, Customer Solutions, Controls Group, and Director of Government and Industry Affairs, Bendix Commercial Vehicle Systems How to maintain advanced safety systems and the wheelend components to help them perform at their best Simple troubleshooting can make the difference between an expensive repair with extended downtime and a quicker, cheaper solution In growing numbers, fl eets are adopting advanced safety systems like full-stability and collision mitigation technologies, and equipping those same vehicles with air disc brakes to optimize performance and protect their safety investment. Th is year, Bendix estimates between 39 and 42 percent of new Class 6 to 8 air-braked commercial vehicles will be built with stability systems, and between 16 and 19 percent will be built with a collision mitigation technology. Additionally, Bendix is forecasting that this year, 16 percent of Class 6 to 8 air-braked wheelends will be equipped with air disc brakes. Beginning in 2017, National Highway Traffi c Safety Administration rules will require electronic stability control systems on most new Class 7 and 8 commercial vehicles. As the technology advances, the maintenance of these safety and braking systems becomes that much more crucial in keeping vehicles operating and in safe working condition. Electronic Issues Bendix technical support teams regularly fi nd that the fi rst response to an electronics problem within an antilock braking system (ABS), or traction, stability or collision mitigation technology, is to replace a component. Oft en, however, the issue is not the component, but a lower-cost problem that can be more diffi cult to detect. Some simple troubleshooting can make the diff erence between an expensive repair with extended downtime and a quicker, cheaper solution. For instance, fi rst responses to an electronic component issue should include examining the wiring and input sensors. Look for frayed wires, corroded connectors, blown fuses, outof position wheel speed sensors or a misaligned radar unit. Other possible causes of issues that don’t require component replacement include a radar sensor that’s blocked by debris or snow, a damaged sensor bracket or J1939 network problems. Obvious damage, such as a crushed radar unit, would naturally require replacement of the part. Th ere are no recommended maintenance practices for repairing the electronics within. Physical Components Th e physical components of a stability or collision mitigation system typically need attention only if certain aspects of the vehicle itself have changed. If the front end has been altered, for instance, or repairs have been conducted, such as front end alignments or steering linkage service, the steering angle sensor will need to be recalibrated according to manufacturer guidelines. Changes in tire size necessitate updating the new tire values using diagnostic support soft ware. Any repairs on the frame rail that call for removal or loosening of the yaw rate/lateral acceleration sensor will require recalibration of the sensor once it has been properly replaced and secured in the same position and orientation. Next Diagnostic Level If no visible reason for the problem is spotted, it’s time to step up to the next level of diagnostics: using your system’s supporting hardware and soft ware. Time spent in pursuit of an accurate diagnosis isn’t wasted. You’ll save time and money in the long run. Make sure you’re using the proper equipment and ensure that the soft ware is up-to-date. Bendix ACom Diagnostic Soft ware is one example of a free downloadable tool, and hardware such as Bendix Remote Diagnostic Units for both tractors and trailers are available from many aft ermarket dealers to troubleshoot brake and safety systems. Refer to the manufacturer’s Service Data Sheets for reference guides and instructions on reading information such as diagnostic unit blink codes. Troubleshooting Steps To properly assess the situation, refer to your stability or collision mitigation system’s troubleshooting instructions for specifi cs. Generally, they will follow these steps: • Run a Power-Up Self Test. On the Bendix Wingman Fusion system, for example, this means powering down the vehicle, putting the key in the “ignition power” position, toggling the cruise control and leaving it in the “on” position and then starting the vehicle, but not driving away. If the system fi nds an issue that will prevent it from functioning properly, it will create an audio alert and log a Diagnostic Trouble Code, depending on the manufacturer. It is possible that while a Diagnostic Trouble Code may point to a specifi c component, it may The right diagnostic equipment and updated software is crucial in troubleshooting and maintaining today’s advanced safety technologies. Photo courtesy of Bendix CHECK THE POSSIBILITIES before replacing the component. 34 FLEET MAINTENANCE ❚ OCTOBER 2016 ❚ VehicleServicePros.com
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