Auto Service Professional

DEC 2018

Magazine for the auto service professional

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40 A S P D e c e m b e r 2 018 A B S vest in the proper tools as well. is Cadillac Es- calade uses two high speed serial data networks — the high speed GMLAN serial data 1 and high speed GMLAN serial data 2. ese are the circuits that do the communicating for the EBCM with the other system modules (see Figure 6). We don't have the space to cover the com- munication circuits and how they work in this article, but the EBCM does play a big part in the overall communication protocol in modern vehicles of today as the braking system is one of the major safety items on a vehicle. As with any vehicle, if the electronic braking system fails, the old reliable hydraulic system takes over until the problem can be addressed at a service facility. Let's take a closer look at an ABS system on a 2012 Ford F-150 pickup truck. is truck has ad- vance track with roll stability control (RSC). e advance track system is made up with the follow- ing systems: conventional ABS, traction control and electronic stability control (ESC). e RSC is an option and works in conjunction with the advance track and incorporates many different systems and components. e ABS module, the HCU or hydraulic control unit, the stability con- trol sensors, steering wheel rotation sensor, hill decent control switch and other components. e first order of business when diagnosing this system is to perform a good visual inspection. Many issues can be caught by performing this step. Next is a capable scan tool so you can access all modules on the vehicle (see Figure 7). When an ABS or traction control indicator light illu- minates on the dash, don't immediately go into that system. Perform an all-system scan because there could be problems in other systems that triggered the ABS light. In the "old" days, if an ABS light was on, it was probably isolated in just the anti-lock braking system. Today there could be multiple systems that could be the cause of the ABS malfunction. Nowadays, you have to think outside of the box. e HCU or hydraulic control unit (see Fig- ure 8) is probably the most expensive part on the ABS system. It houses the EBCM which in most cases is serviced separately and the control so- lenoids and/or valves that control the direction and pressure of the of the brake system. Figure 3: The scan tool must be able to access ABS data and must be updated.

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