GM Service Manual Online
For 1990-2009 cars only

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

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

ECT Sensor

Cooling/HVAC

°C/°F

Varies

FC Relay 1 Command

Cooling/HVAC

ON/OFF

OFF

FC Relay 2 and 3 Command

Cooling/HVAC

ON/OFF

OFF

FC Relay 1 Circuit Status

Cooling/HVAC

OK/Open/Short Gnd/Short to B+/Incomplete

OK

FC Relay 2 and 3 Circuit Status

Cooling/HVAC

OK/Open/Short Gnd/Short to B+/Incomplete

OK