For a complete wiring diagram Refer to Section 8W

Theory of Operation

The EGR Air Flow Control Valve is a three-wire electrically operated throttle valve motor used to assist the EGR system function by creating a vacuum in the intake system to draw exhaust gas into the intake manifold. The Solenoid receives 12 volts from the ECM/ASD relay, ground and a pulse-width modulated ground signal from the ECM. With the solenoid de-energized (off) the throttle valve is in the open (full flow) position. When the ECM energizes (grounds) the throttle motor, the throttle valve closes creating a low pressure (vacuum) effect in the intake system. This low pressure effect helps draw exhaust gases from the EGR Valve into the intake system.

• When Monitored:

  With the ignition on and the ECM EGR Air Flow Control Valve command on.

• Set Condition:

  The ECM detects excessive current on the EGR Air Flow Control Valve Control circuit for 0.5 second.

Diagnostic Test

NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.