GM Service Manual Online
For 1990-2009 cars only
Table 1: Heating and Air Conditioning Scan Tool Data List
Table 2: ECM Scan Tool Data List
Table 3: Vehicle Control Systems ECU Identification Information - HVAC

Use the Scan Tool Data Display Values and Definitions Information in order to assist in diagnosing the HVAC control module concerns. Compare the vehicles actual scan tool data with the typical data display value table information. Use the data information in order to aid in understanding the nature of the concern when the vehicle does not match with the typical data display values.

The scan tool data values were taken from a known good vehicle under the following conditions:

    • The ignition switch is in the ON position.
    • The engine is running at idle.
    • The vehicle is in PARK.
    • The doors are closed.
    • The windows are closed.
    • The A/C is ON.
    • The ambient air temperatures are at 22-27°C (70-80°F).

Heating and Air Conditioning 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 System Data, Module and Display Data

Yes/No

Yes

Ambient Air Temp. Sensor

HVAC System Data, Sensor Data, Module and Display Data

°C/°F

Varies

Blower Motor Speed

HVAC System Data

%

Varies

Blower Motor Speed Command

HVAC System Data

%

Varies

Compressor Clutch Status

HVAC System Data

OFF/Auto

Auto

Driver Program Number

Module and Display Data

Counts

Varies

Driver Temp. Dr. Cal. Range

Actuator Data

Pulses

Varies

Driver Temp. Dr. Motor Command

Actuator Data

Counts

Varies

Driver Temp. Dr. Position

Actuator Data

Counts

Varies

Driver Temp. Dr. Position

Actuator Data

Pulses

Varies

Inside Air Temp. Sensor

HVAC System Data, Sensor Data, Module and Display Data

°C/°F

Varies

LED Intensity

Module and Display Data

Counts

Varies

Left Sunload Sensor

Sensor Data

Counts

Varies

Load Management Status

Module and Display Data

ON/OFF

OFF

Lower Left Duct Temp. Sensor

Sensor Data

Counts

Varies

Lower Right Duct Temp. Sensor

Sensor Data

Counts

Varies

Mode Dr. Cal. Range

Actuator Data

Pulses

Varies

Mode Dr. Motor Command

Actuator Data

Counts

Varies

Mode Dr. Position

Actuator Data

Counts

Varies

Mode Dr. Position

Actuator Data

Pulses

Varies

Mode Status

HVAC System Data, Module and Display Data

Auto, Panel, Lower, Bi-level, Defog, Defrost, Off

Varies

Psgr. Program Number

Module and Display Data

Counts

Varies

Psgr. Temp. Dr. Cal. Range

Actuator Data

Pulses

Varies

Psgr. Temp. Dr. Motor Command

Actuator Data

Counts

Varies

Psgr. Temp. Dr. Position

Actuator Data

Counts

Varies

Psgr. Temp. Dr. Position

Actuator Data

Pulses

Varies

Recirculation Dr. Cal. Range

Actuator Data

Pulses

Varies

Recirculation Dr. Motor Command

Actuator Data

Counts

Varies

Recirculation Dr. Position

Actuator Data

Counts

Varies

Recirculation Dr. Position

Actuator Data

Pulses

Varies

Right Sunload Sensor

Sensor Data

Counts

Varies

Upper Left Duct Temp. Sensor

Sensor Data

Counts

Varies

Upper Right Duct Temp. Sensor

Sensor Data

Counts

Varies

Valet Switch

Module and Display Data

Active/Inactive

OFF

Vehicle Speed

HVAC System Data

Km/h/mph

Varies

ECM 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 Off for WOT

ECM

Yes/No

No

A/C Pressure Disabled

ECM

Yes/No

No

A/C Refrigerant Pressure Sensor

ECM

kPa/psi

Varies

A/C Refrigerant Pressure Sensor

ECM

Volts

Varies

A/C Relay Command

ECM

Yes/No

Yes

A/C Request Signal

ECM

Yes/No

Yes

ECT Sensor

ECM, EVAP Data, Fuel Trim Data, Misfire Data, CMP Actuator Data

°C/°F

Varies

Vehicle Control Systems ECU Identification Information - HVAC

Scan Tool Parameter

Data List

ID Number

Operating Conditions: Ignition ON

8-Digit GM Part Number

Module Information 1

8 Digit ID Number

Calibration ID

Module Information 2

8 Digit ID Number

Prom ID

Module Information 1

8 Digit ID Number

Software Part Number

Module Information 2

8 Digit ID Number