GM Service Manual Online
For 1990-2009 cars only

Powertrain Control Module (PCM) Scan Tool Output Controls

Scan Tool Output Control

Additional Menu Selections

Description

Fans Low Speed

Fan Relays

The scan tool displays a Commanded State of None, Off or On. This allows you to communicate with the PCM and activate or deactivate the cooling fan 1 relay, manually turning the low speed fans On and Off.

Fans High Speed

Fan Relays

The scan tool displays a Commanded State of None, Off or On. This allows you to communicate with the PCM to activate or deactivate the cooling fan 1 relay, manually turning the low speed fans On. After a 3 second delay the PCM will activate the cooling fan 2 relay and the cooling fan 3 relay. This turns the high speed fans On and Off.