GM Service Manual Online
For 1990-2009 cars only
Table 1: Body Control Module (BCM) Scan Tool Data List
Table 2: Engine Control Module (ECM) Scan Tool Data List (L81)

Use the Scan Tool Data Display Values and Definitions Information in order to assist in diagnosing the HVAC Control Assembly 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 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 (RPO C60)

HVAC Data

Yes/No

Yes

Engine Control Module (ECM) Scan Tool Data List (L81)

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 High Side Pressure

General Info-Outputs

0 to 5 Volts

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