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Home >> Pontiac >> 2000 >> Firebird Base, 2D Convertible, Automatic >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Control System - Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P1637: Charging System Light Control Circuit (Grand PRIX) >> Circuit Description
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Circuit Description

Output Driver Modules (ODMs) are used by the PCM to turn on current-driven devices that are needed to control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by controlling the ground circuit when PCM is commanding ON. ODMs have the capability of diagnosing each output circuit individually.

DTC will also set when an improper voltage level has been detected on the output circuit which controls the A/C compressor relay and condition is present for at least 30 seconds.