Electronic Brake Traction Control Module (EBTCM)

The controlling element of ABS VI/Traction Control System (TCS) is a microprocessor based Electronic Brake Traction Control Module (EBTCM). Inputs to the system include four wheel speed sensors, the brake switch, switched ignition voltage, unswitched ignition voltage, and serial data communications with the Powertrain Control Module (PCM). Outputs include five bi-directional motor controls, four indicator controls, two solenoid controls (ABS), and the electronic brake control relay. A serial data link, located in terminal 9 of the Data Link Connector (DLC), is provided for service diagnostic tools and assembly plant testing. The EBTCM monitors the speed of each wheel. If any wheel begins to approach lock-up and the brake switch is on, the EBTCM controls the ABS motors and solenoids to reduce brake pressure to the wheel approaching lock-up. Once the wheel regains traction, brake pressure is increased until the wheel again begins to approach lock-up. This cycle repeats until either the vehicle comes to a stop, the brake is released, or no wheels approach lock-up. Additionally, if one or more of the drive wheels are accelerating too rapidly, the EBTCM sends commands to the adjuster assembly motor, to the PCM to reduce engine torque and to the TCS motors to apply and release the brakes several times each second to reduce driven wheel speed to a prescribed amount over the non-driven wheel speed. Once the wheel regains traction, brake pressure is decreased and engine torque reduction is no longer requested. This cycle repeats until traction control is no longer necessary. The EBTCM monitors itself, each input and each output for proper operation. If any system malfunction is detected, the EBTCM will store a DTC in nonvolatile memory (DTC's will not disappear if the battery is disconnected).