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Home >> Chevrolet >> 2005 >> Aveo Base, 4D Hatchback >> Repair and Diagnosis >> External Pages >> Different car >> Section 50 (Engine Controls - 1.6L (L91) (DTC P0300 To DTC P0488)) >> Diagnostic Information & Procedures >> DTC P0401 >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 2004 Suzuki Swift + and 2004 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.

The engine control module (ECM) performs a flow test on the exhaust gas recirculation (EGR) system during deceleration. The ECM does this by momentarily commanding the EGR valve to open while monitoring the signal of the manifold absolute pressure (MAP) sensor and the EGR position sensor. If the MAP signal is incorrect for the EGR pintle position, the ECM records the amount of MAP difference that was detected and adjusts a calibrated fail counter towards a calibrated fail threshold level. The number of EGR flow tests required to exceed the fail threshold may vary according to the amount of detected EGR flow error. If the ECM detects an EGR flow error, DTC P0401 sets.