GM Service Manual Online
For 1990-2009 cars only

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).

PCM 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 Clutch (Actual)

A/C Information

On/Off

Off

A/C High Side Pressure

Engine Data 2

Volts

0-5.00 Volts

A/C Press. Out Of Range

Engine Data 2

Yes/No

No

A/C Relay

Engine Output Controls

On/Off

Off

A/C Relay

Output Driver Data

OK/Fault

OK

Commanded A/C

Engine Data 2

On/Off

Off