Valve Block

The valve block, which is attached to the bottom of the booster/master cylinder assembly, contains 4 wheel circuit solenoid valves (one for each wheel) and the replenishing valve. The replenishing valve serves to maintain pedal height while in anti-lock mode, or during hard braking without anti-lock operation, by redirecting brake fluid from the booster servo circuit into the master cylinder. A 12-pin connector is included on the valve block to provide electrical connections for the valve solenoids.

1. Wheel Circuit Valves
   
   One solenoid valve is included for each of the 4 wheel circuits (LF, RF, LR, RR). Each is a 3 position valve which allows for pressure increase, pressure hold and pressure reduction modes during anti-lock operation. The position of each valve is determined by the amount of current which flows through the valve solenoid coil. Current flow through the valve coil is controlled by the EBCM. During normal braking, the wheel circuit valves are not activated.
2. Replenishing Valve
   
   The replenishing valve is a 2 position valve which is also controlled by the EBCM. This valve is opened during anti-lock mode and also during extremely hard braking without anti-lock operation. When the replenishing valve is engaged, pressurized brake fluid from the booster servo circuit is redirected into the master cylinder to prevent excessive pedal travel.