GM Service Manual Online
For 1990-2009 cars only

Scan Tool Data List 8.1L (L18)

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).

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 Feedback Sig

Engine Data 2

Relay On/Relay Off

Relay On

A/C Compressor Cycling

Engine Data 2

1=Normal/0=Low Pressure

1=Normal

A/C Relay

Engine Output Controls

On/Off

Off

A/C Relay Command

Engine Data 2

On/Off

On

A/C Request Signal

Engine Data 1, Engine Data 2 and EGR Data

Yes/No

Yes

A/C Sec. High Pressure

Engine Data 2

1=Normal/0=High Pressure

1=Normal

Scan Tool Data List 6.5L (L65)

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).

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 Relay

Engine Output Controls

On/Off

Off

A/C Relay Command

Engine Data 1

On/Off

On

A/C Request

Engine Data 1

Yes/No

Yes