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Home >> GMC >> 1991 >> Syclone V6-262 4.3L Turbo >> Repair and Diagnosis >> Powertrain Management >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Testing and Inspection >> Initial Inspection and Diagnostic Overview
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Initial Inspection and Diagnostic Overview


A technician may request the ECU to perform a function test by grounding ALDL terminal H to A once for 2 seconds. This will activate the motor and the valves. The ignition must be cycled after each attempt to prevent a false code from being set.