Exhaust Gas Recirculation (EGR) Cooler Bypass (if equipped)

The engine vacuum pump, mounted in the front engine cover housing, supplies vacuum to the EGR cooler bypass solenoid valve during engine operation. When commanded by the Engine Control Module (ECM), the EGR cooler bypass solenoid valve supplies vacuum to the EGR Cooler Bypass Valve Actuator, allowing hot exhaust gas to heat the intake air in the manifold. Once the engine operating temperature is reached, the ECM will command the EGR cooler bypass solenoid valve to shut off the vacuum supply to the EGR cooler bypass valve actuator, closing the hot exhaust gas flow. The cooler bypass valve allows cooling of the exhaust gases during high engine load operation or exclusion of the cooling process during idle and light engine load applications.