Cooler Bypass Valve

Each valve housing contains a cooler bypass valve, which either allows the exhaust gasses to flow direct to the electric throttle or diverts them through the EGR cooler.

A vacuum actuator is located on a bracket attached to each EGR cooler to operate the cooler bypass valves. The actuators receives a vacuum which is produced by the vacuum pump located at the rear of the engine. Each vacuum actuator is connected to its related bypass valve by an actuator rod.

The vacuum supply to the actuators is controlled by the ECM. When bypass control is required, the ECM energizes a cooler bypass valve solenoid, which applies vacuum to the vacuum actuators. The vacuum causes the actuators to move the connecting rods in a linear direction. The linear movement of the rods is transferred to rotary movement of the cooler bypass valves within the valve housings.

Cooler Bypass Valve Closed 

When the cooler bypass valve is closed, exhaust gasses are directed through the cooler before being passed to the electric throttle.

Cooler By-Pass Valve Open 

When the cooler bypass valve is open, exhaust gasses are passed directly through the valve housing into the electric throttle with no cooling applied to the gasses.