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Home >> Pontiac >> 1998 >> Firebird Formula, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - 5.7L >> Diagnostic Trouble Codes >> DTC P0804 - Skip Shift Light Control Circuit >> Circuit Description

Circuit Description

Voltage is supplied directly to skip shift light. PCM controls shift light signal by grounding this circuit through an internal switch called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM.

When PCM is commanding a component ON, voltage of control circuit should be low (near zero volts). When PCM is commanding control circuit to a component OFF, voltage potential of circuit should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, fault line status will change, causing DTC to set.

Conditions for setting DTC: