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Home >> Pontiac >> 2000 >> Firebird Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Engine Control System Self-Diagnostics - 5.7L) >> Diagnostic Tests >> DTC P1639: 5-Volt Reference No. 2 Circuit ("F" Body) >> Circuit Description
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Circuit Description

WARNING: This page is about a different variant/trim than selected.

PCM uses a common 5-volt reference circuit as a sensor feed to fuel tank pressure sensor, fuel tank level sensor, and TP sensor. PCM monitors voltage on 5-volt reference circuit. If 5-volt reference circuit is out of range for greater than 2 seconds, DTC will set.