GM Service Manual Online
For 1990-2009 cars only

Powertrain Control Module (PCM) or Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition Switch in RUN/Engine running/Automatic Transmission in PARK/Air Conditioner is OFF

ECT

Inputs/Outputs

°C/°F

Varies

FC Relay 1 Command (Fans Low Speed)

Outputs

ON/OFF

OFF

FC Relays 2 and 3 Command (Fans High Speed)

Outputs

ON/OFF

OFF