GM Service Manual Online
For 1990-2009 cars only
Table 1: Body Control Module (BCM)
Table 2: Engine Control Module (ECM) - L61/2.2L
Table 3: Powertrain Control Module (PCM) - L66/3.5L

Use the Scan Tool Data Display Values and Definitions Information in order to assist in diagnosing the HVAC Control Module problems. 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 problem 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).

Body Control Module (BCM)

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

Switch Inputs

Yes/No

Yes

A/C Sensor

Accessory

Volts

Varies

After Blow Relay Command

Accessory

On/Off

Varies

After Blow Relay Feedback

Accessory

High/Low

Varies

Engine Control Module (ECM) - L61/2.2L

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 High Side Pressure

General Info Outputs

kPa/psi

Varies

A/C High Side Pressure

General Info Inputs/Outputs

0--5Volts

Varies

A/C Relay Command

General Info Inputs/Outputs/

On/Off

On

A/C Request

General Info Inputs

Yes/No

Yes

ECT

All

°C/°F

Varies

Powertrain Control Module (PCM) - L66/3.5L

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 High Side Pressure

General Info Inputs

kPa/psi

Varies

A/C Pressure Sensor

General Info Inputs

0--5Volts

Varies

A/C Relay Command

General Info Inputs/Outputs

On/Off

On

A/C Request

General Info Inputs

Yes/No

Yes

ECT

All

°C/°F

Varies