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Home >> Buick >> 2009 >> Allure CX >> Repair and Diagnosis >> Body & Frame >> Ignition Switch/Steering Lock >> Immobilizer System >> Diagnostic Information and Procedures >> DTC P1631 >> Circuit/System Description

Circuit/System Description

The body control module (BCM) sends the fuel enable password to the engine control module/powertrain control module (ECM/PCM) via the serial data circuit. The ECM/PCM compares this password to the learn password. If the learned password matches the password received from the BCM, the ECM/PCM will allow vehicle starting.