GM Service Manual Online
For 1990-2009 cars only
Table 1: HVAC Control Module Scan Tool Data List
Table 2: PCM Scan Tool Data List 3.5L (LX9) / ECM 3.9L (LZ9)

HVAC Control Module Scan Tool Data List

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine Idling, A/C ON, Ambient Air Temperature Between 22-27°C (70-80°F)

A/C Request

HVAC

Yes/No

Varies

Recirculation Dr. Position

HVAC

Counts

Varies

Recirculation Dr. Motor Command

HVAC

Counts

Varies

Mode Dr. Position

HVAC

Counts

Varies

Mode Dr. Motor Command

HVAC

Counts

Varies

Defrost Dr. Position

HVAC

Counts

Varies

Defrost Dr. Motor Command

HVAC

Counts

Varies

Driver Temp. Dr. Position

HVAC

Counts

Varies

Driver Temp. Dr. Motor Command

HVAC

Counts

Varies

Psgr. Temp. Dr. Position

HVAC

Counts

Varies

Psgr. Temp. Dr. Motor Command

HVAC

Counts

Varies

Aux. Mode Dr. Position

HVAC

Counts

Varies

Aux. Mode Dr. Motor Command

HVAC

Counts

Varies

Aux. Temp. Dr. Position

HVAC

Counts

Varies

Aux. Temp. Dr. Motor Command

HVAC

Counts

Varies

Evaporator Temp. Sensor

HVAC

°C/°F

Varies

Evaporator Temp. Sensor

HVAC

Counts

Varies

Mode Status

HVAC

Recirc/Vent/ Mix-Blend/ Floor/ Bi-Level/ Defrost

Varies

A/C LED

HVAC

On/Off

Varies

Rear Defrost LED

HVAC

On/Off

Varies

Driver Heated Seat Status

HVAC

Off/Low Heat/High Heat

Varies

Passenger Heated Seat Status

HVAC

Off/Low Heat/High Heat

Varies

Blower Motor Switch Position

HVAC

Off/On but not High Blower/On and High Blower

Varies

Aux. Blower Motor Speed Command

HVAC

Counts

Varies

Aux. Blower Motor Switch Position

HVAC

Aux/Off/1/2/3/4

Varies

Aux. Blower Motor Speed

HVAC

Counts

Varies

PCM Scan Tool Data List 3.5L (LX9) / ECM 3.9L (LZ9)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine Idling, A/C ON, Ambient Air Temperature Between 22-27°C (70-80°F)

A/C Disengage Reason

HVAC

None/WOT/System Voltage/CKP Learn Active/Engine Run Time/Coolant Hot/Stall Prevention/ A/C Pressure/Engine Speed/Trans Engine Speed/ A/C Pressure Sensor/Low Voltage/High Voltage/Outside Air Temp/Switched OFF

Varies

A/C Off for WOT

HVAC

Yes/No

Varies

A/C Pressure Disable

HVAC

Yes/No

Varies

A/C High Side Pressure

HVAC

kPa/Psi

Varies

A/C High Side Pressure

HVAC

Volts

Varies

A/C Relay Command

HVAC

On/Off

Varies

A/C Relay Circuit History

HVAC

OK/Open/Short/Invalid State

Varies

A/C Request Signal

HVAC

Yes/No

Varies