For 1990-2009 cars

Table 1: | HVAC Control Module Scan Tool Data List
Table 2: | Powertrain Control Module (PCM) Scan Tool Data List (L61)
Table 3: | 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 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).

#### HVAC Control Module 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)
Auto Switch - Actual | Defrost/Actuator Data | High/Low | Varies
Auto Switch Cmd | Actuator Data | On/Off | Varies
Defrost Switch - Actual | Defrost Data | High/Low | Varies
Defrost Switch Cmd | Defrost Data | On/Off | Varies
Defrost LED | Defrost Data | On/Off | Varies
Economy Switch - Actual | Defrost/Actuator Data | High/Low | Varies
Economy Switch Cmd | Actuator Data | On/Off | Varies
Fan Speed | Defrost/Actuator Data | Counts | Varies
Mix Fdbk | Actuator Data | Counts | Varies
Mode Switch - Actual | Actuator Data | High/Low | Varies
Mode Switch Cmd | Actuator Data | On/Off | Varies
Mode Fdbk | Actuator Data | Counts | Varies
Off Switch - Actual | Defrost/Actuator Data | High/Low | Varies
Off Switch Cmd | Actuator Data | On/Off | Varies
Outside Air Temp | Defrost/Actuator Data | Counts | Varies
Psgr. Compartment Temp | Defrost/Actuator Data | Counts | Varies
Rear Defrost Switch - Actual | Defrost Data | High/ Low | Varies
Rear Defrost Switch Cmd | Defrost Data | On/Off | Varies
Rear Defrost Fdbk | Defrost Data | High/ Low | Varies
Recirc LED | Actuator Data | On/Off | Varies
Recirc Switch - Actual | Actuator Data | High/Low | Varies
Recirc Switch Cmd | Actuator Data | On/Off | Varies
Solar Sensor | Defrost/Actuator Data | Counts | Varies

#### Powertrain Control Module (PCM) Scan Tool Data List (L61)

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-Inputs/Outputs | 0 to 5 Volts | Varies
A/C Relay Command | General Info-Inputs/Outputs | On/Off | On
A/C Relay Circuit Open or Short to Ground | General Info-Outputs | Yes/No | No
A/C Relay Circuit Short to Volts | General Info-Outputs | Yes/No | No
A/C Request | General Info-Inputs/Outputs | Yes/No | Yes
ECT | All | C/F | Varies

#### 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