Pressure Limit Valve

Based upon wheel speed input signals, RWAL ECM controls hydraulic brake pressure to both rear wheels. Under normal conditions, RWAL system functions as a conventional brake system.

Normal wheel speed-to-acceleration/deceleration braking is programmed into RWAL ECM memory. If the difference between optimum braking rear wheel speed and actual braking rear wheel speed exceeds programmed limits, RWAL system will enter anti-lock mode.

In anti-lock mode, pressure to rear wheel hydraulic circuit is modulated by RWAL ECM through pressure limit valve. This prevents rear wheel lock-up, while providing maximum stopping power and directional stability. Pressure limit valve is located under master cylinder on 2-door models, or next to master cylinder on 4-door models. The pressure limit valve consists of 2 valves: a dump valve that releases pressure into an accumulator and an isolation valve that maintains rear wheel hydraulic pressure.

During anti-lock operation, a series of rapid pulsations (caused by fluctuation of pressure limit valve) will be felt at the brake pedal. These pulsations, in conjunction with tire "chirping" (on dry pavement), are considered normal during anti-lock operation and will cease when normal braking is resumed or vehicle comes to a complete stop.