Traction Control: Operation

When either rear tire begins slipping during acceleration, ABS/TRAC ECU pulses rear brakes to prevent rear wheels from slipping. The driver has the option of activating or deactivating TRAC. TRAC OFF switch (also referred to as TRAC cut switch) and TRAC OFF indicator light are located on instrument panel.

Pressing TRAC OFF switch turns TRAC off. Pressing TRAC OFF switch again turns system on. System is reset to on when engine is restarted. When system is on, SLIP indicator light (also referred to as TRAC indicator light), located on instrument panel, blinks. When a malfunction occurs and ABS/TRAC ECU sets a diagnostic code, the TRAC OFF indicator light blinks. Signals are send between ABS/TRAC ECU and Engine Control Module (ECM) to monitor traction control system.

ABS/TRAC actuator consists of a pump and accumulator assembly which produces fluid pressure regulated in disc brake calipers of each rear wheel. This function is also controlled by signals from ABS/TRAC ECU.

Brake fluid pressure to right and left rear wheels is controlled separately in three control modes (pressure increase, holding and pressure reduction). This process is controlled by solenoid valves, pressure switches and sensors.

When a malfunction occurs, TRAC system becomes inoperative. Engine and brake systems operate normally. ABS/TRAC ECU continues normal control even when a malfunction occurs.