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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 84 (Engine Control System Self-Diagnostics - 3.1L Engine) >> Diagnostic Tests >> DTC P0404: EGR System >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The Powertrain Control Module (PCM) monitors the Exhaust Gas Recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. The PCM compares the EGR position sensor with desired EGR position when the valve is commanded open. If the difference between the EGR position sensor and desired EGR position is more than 15 percent this DTC will set.