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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1044 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0237 To P0611)) >> Diagnosis >> DTC P0489 >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The exhaust gas recirculation (EGR) valve is vacuum operated. Vacuum for the EGR valve control system is supplied by a belt driven vacuum pump. The EGR valve vacuum control solenoid and the EGR valve vacuum vent solenoid work together to control the position of the EGR valve. The EGR valve vacuum control solenoid is supplied with 12 volts through the ignition 1 circuit. The EGR valve vacuum control solenoid is pulse width modulated through the EGR valve solenoid control circuit by the engine control module (ECM). The ECM monitors the voltage on the EGR valve vacuum solenoid control circuit. If the ECM detects a low voltage condition on this circuit, DTC P0489 sets.