Circuit/System Description

WARNING: This page is about a different variant/trim than selected.

The reductant purge valve controls the flow of diesel exhaust fluid (DEF). In the normally de-energized state, the purge valve directs reductant from the pump to the reductant injector. When the ignition is turned Off, the engine control module (ECM) energizes both the reductant purge valve and reductant pump for about 30 to 45 seconds to purge the supply line of reductant. The ECM also commands the reductant injector to 100% to prevent vacuum from forming during the purge process. Purging prevents the reductant from freezing in the pump or supply line to the reductant injector. The ECM will set a DTC when an abnormal voltage condition on the purge valve circuit is detected.

The ECM provides battery voltage on the actuator high control circuit and ground on the actuator low control circuit. Both circuits are controlled through output drivers within the ECM. The ECM monitors the voltage on the circuits to detect a failure.