ABS and stability control

ADAS technologies build on the foundation of antilock braking systems (ABS) and electronic stability control (ESC). If a fault occurs in either the ABS or ESC system, the ADAS system may be unavailable.

“One ABS concern centers on wheel-speed sensors, which can be susceptible to chassis harness issues such as rubs and chafing, as well as issues occurring when service is done at the wheel-end,” said Brian Screeton, Bendix manager for technical training and service. “The sensor may become nonfunctional, a wire may be severed, or a sensor is not close enough to the tone ring.”

A stability control issue might be the steering angle sensor falling out of calibration, which can sometimes happen after a front-end alignment, making it important to calibrate the sensor after any front-end work.

“Another stability control issue is rare but does occur,” Screeton said. “It’s the incorrect placement of a lateral acceleration/yaw rate sensor after work on the frame rail or chassis modifications. If this sensor is moved or not returned to the correct orientation, then a fault may result with the stability control system.”

Sometimes systems can show a diagnostic trouble code (DTC) that can be cleared by a simple key cycle of the ignition key, done in a safe area, Screeton notes. DTCs like this can be caused by road conditions or the terrain that the vehicle is operating in, so always first try to clear the DTC by restarting the vehicle. If it returns after restarting, then take the vehicle to a qualified repair facility immediately.

Focus on the radar

Some radar issues, if they occur, can be caused by sensor misalignment, vehicle wiring, or active DTCs in other components of the vehicle, like the engine, for example. Modern or next-generation radar systems are better able to compensate for minor sensor alignment issues than earlier ADAS radar systems.

It’s important to have all radar issues evaluated by a trained professional to ensure that the system is working properly.

“Radar misalignment means that the radar is not pointing in the right direction,” Screeton said. “This is due usually to improper installation after a repair or after a collision with something that strikes the radar or its mounting. For Bendix, realigning the radar involves following the procedure in the corresponding Bendix service data sheet, searchable at B2Bendix.com.”

In addition, Screeton advised checking the radar bracket for damage, along with the mounting surface on the chassis. Repairing or replacing damaged components can help maintain proper radar alignment.

Because the radar is mounted at the front of the vehicle, its connector can be exposed to a variety of chemicals. This is especially true in areas where salt, sand, and other materials are used to improve traction during snow and ice. Make sure the connector is properly covered, sealed, and secured to help minimize corrosion caused by repeated exposure to road chemicals.

“Remember, too, that radars are designed to detect when they don’t ‘see’ the environment as expected,” Screeton said. “This functionality is typically referred to as radar blindness, which may occur if the radar doesn’t detect a valid object for a certain amount of time. Too few valid radar targets over a period of time can cause the radar to indicate a DTC. This might happen on long stretches of barren highway or desert where other vehicles and radar targets are nonexistent. Typically, an ignition key cycle will reset the radar and the system will resume.”

Focus on the camera

Camera issues may be related to camera placement, a blocked field of view, or the chassis wiring harness. The first step is to verify that the camera is properly plugged in and connected. Also keep the following in mind:

• Frayed, cut, or improperly repaired chassis wiring can cause camera issues, just as it can with other vehicle systems. For less obvious problems, check the chassis harness first.
• “Camera blindness is usually a temporary, self-correcting occurrence, possibly due to sun and/or fog,” Screeton said. “However, if the camera is blocked by something—like a large bug or a piece of tape—then this will also cause a problem.”
• Has the windshield been replaced? If so, then install the camera using the correct bracket in the original OEM installation location to ensure proper function.

For any repairs associated with potential camera issues, follow the procedure in the corresponding Bendix service data sheet, searchable at B2Bendix.com.

Issues with software and the ECM

Issues with Bendix systems can occur when improperly installed or incompatible aftermarket components are added to the vehicle’s J1939 datalink network.

According to Screeton, connectors and connection types are frequently the source of the problem.

“However, issues involving aftermarket component compatibility also create communication concerns,” he said. “Don’t overlook a chassis wire that has rubbed on a metal piece creating a shorted or an open circuit—it typically leads to the inability to connect to the component for diagnostics since diagnostics is performed using the same 1939 CAN communication lines.”

And note this critical point, said Screeton: If the engine electronic control module (ECM) is replaced, then the replacement ECM must be correct for the truck. Bendix’s stability control electronic control units (ECUs) require a match to the VIN to ensure the proper parameters are uploaded for the system.

Tools at hand

Every driver should carefully review the operator’s manual to understand the ADAS alerts and notifications they may encounter during operation. Drivers should also be familiar with how the system is designed to operate, as well as its limitations, so they can more easily recognize when something may not be functioning properly.

“Having a diagnostic tool that shows the DTCs of the full vehicle is important, as well,” Screeton said. “The diagnostic software for Bendix systems is Bendix ACom AE. When connected to a vehicle, the software automatically detects and gathers active and inactive DTCs from all Bendix electronic control units on the vehicle, as well as key vehicle ECUs, like the engine and transmission.”

Screeton encourages technicians to take advantage of available training. Bendix offers three- and two-day Brake School sessions, along with virtual classes and the Bendix On-Line Brake School at brake-school.com. The training helps technicians better understand, troubleshoot, and repair systems. The Bendix On-Line Brake School courses are accessible for no charge when users register with the site.

“Remember that ADAS systems, like vehicles, can be unique,” Screeton noted. “One-size-fits-all training isn’t going to be as helpful as training focused on repairing the specific system of concern.”

The issues described in this installment of Tech Tips are not meant to exhaustively cover what can occur with ADAS technologies, nor are they applicable to all technologies on all vehicles. The content refers to Bendix advanced driver assistance systems, not autonomous vehicle systems or systems offered by other companies. Information regarding system repairs for specific systems should be referenced to ensure proper repair, maintenance, and operation of the system.

Bendix emphasizes that advanced driver assistance technologies complement safe driving practices. No commercial vehicle safety technology, including Bendix safety technologies, replaces a skilled, alert driver exercising safe driving techniques and proactive, comprehensive driving training. Responsibility for the safe operation of the vehicle remains with the driver at all times. Never wait for the system to intervene. Every driver should carefully review the operator’s manual and be trained by the fleet or vehicle owner on the proper operation and limitations of the ADAS system during operation.