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Home >> Buick >> 1995 >> LeSabre Custom >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Tests W/Codes) >> ECM/Pcm Code Charts >> Code P0401, (EGR) Flow Test Failure >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 1995 Oldsmobile Ninety-Eight and 1995 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.

PCM tests exhaust gas recirculation valve by momentarily commanding valve on while monitoring engine RPM. PCM will illuminate Malfunction Indicator Light (MIL) and store Code P0401 if expected drop is not seen for a calibrated number of tests.

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