For a complete wiring diagram Refer to Section 8W

Theory of Operation

The EGR Air Flow Control Valve is a two-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 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) 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 off.

• Set Condition:

  The ECM detects an open 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.

NOTE: An open ECM power supply to the ECM will cause multiple DTC's including this DTC to set.

NOTE: Check the ECM for other DTC's. If other DTC's are set with this DTC refer to the symptom list and perform the CHECKING THE ECM POWER AND GROUND CIRCUITS test before continuing.

NOTE: Ensure the ECM and EGR Air Flow Control Valve harness connectors are connected.