Anti-lock brake systems (ABS) and the HCU are replacing proportioning, combination and other valves to change the braking forces in the front and rear. This is called Electronic Brake Distribution (EBD) and it can dynamically change to proportioning to take into account if the vehicle is turning or is loaded.
The system can also use EBD to perform a “soft stop.” This routine is performed when a vehicle is slowing at low speeds and the brake force is varied in the front and rear so the vehicle’s attitude is controlled and weight is evenly transferred. This means a flatter and more stable stop.
If the ABS light it on, the system may go into a default setting with a static braking force distribution level. The customer may notice lock-up or difficulty modulating pedal force.
The software running the EBD system is calibrated by engineers to the vehicle in computer simulations and on test tracks. Most of the time they get it right. But, sometimes problems are not discovered until the vehicle is on the road being driven by the public.
Sometimes the program/calibration for the ESC system needs a little “tweaking” due to changes in the vehicle, like a new tire size, vehicle weight or unforeseen driver behaviors. This is where SAE J2534 reflashing comes into play. Some OEMs like Honda and Chrysler have released updates to enhance pad wear and other braking behaviors.
This is why checking TSBs on a vehicle is critical if the customer or technician notices abnormal wear problems like the rear brakes wearing out before the fronts.
Most OEMs are very protective of their reflash programs. The growing trend is that the new program does not reside on the hard drive or memory of the reflash tool. Instead, the program is directly burned onto the module from the internet. Most of the OEMs site piracy and intellectual property concerns, which is valid since the cost to write the code and test the calibrations is very expensive.
AVI A5 Test Prep Video
addresses the symptoms and causes of the extensive hydraulic braking systems, drum brake, disc brake, parking brake, power assist unit and anti-lock brake system diagnostic information.
You can be certain that with over 5 hours of video and a training manual by AVI this training program has everything you need to know about brakes.