EGR Control

The EGR control system prevents recirculation of exhaust gases when coolant temperature is below 135°F (57°C). The coolant temperature sensor constantly monitors and informs the ECU of coolant temperature. When the temperature is below the specified value, the ECU opens the Vacuum Switching Valve (VSV) to prevent EGR flow.

When coolant temperature exceeds the specified value, the ECU closes the VSV to allow EGR flow. The vacuum modulator opens at idle speeds to prevent EGR flow when coolant temperature exceeds the specified value.