GM Service Manual Online
For 1990-2009 cars only

Engine Control Module (ECM) Scan Tool Output Controls

Scan Tool Output Control

Additional Menu Selection(s)

Description

Fan Relay 1

Fan Relays

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

Fan Relay 2

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.