GM Service Manual Online
For 1990-2009 cars only
BCM -- A/C Request: The scan tool displays Yes/No. Yes is displayed when the body control module (BCM) receives an input from the HVAC control assembly for an A/C request.

BCM -- Afterblow: The scan tool displays Active/Inactive/Requested/Pending selections. This allows you to view the mode afterblow is in. Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned off.

BCM -- Ambient Air Temperature Sensor: The scan tool displays 0-5 volts. The voltage displayed represents the value of the ambient air temperature sensor signal.

BCM -- Blower Motor Relay Command: The scan tool displays On/Off. On is displayed when the blower motor switch is in the HIGH position.

ECM -- A/C Disengage History: The scan tool displays the last reason the A/C compressor was disengaged

ECM -- A/C High Side Pressure Sensor: The scan tool displays 0 to 4000 kPa (0 to 580 psi). The output of the A/C pressure sensor.

ECM -- A/C High Side Pressure Sensor: The scan tool displays 0 to 5 volts. The output of the A/C pressure sensor.

ECM -- A/C Off For WOT: The scan tool displays Yes or No. Yes is displayed when the ECM de-energizes the A/C compressor clutch relay to reduce engine load during wide open throttle.

ECM -- A/C Pressure Disable: The scan tool displays Yes or No. Yes is displayed when the system pressure exceeds 2968 kPa (430 psi).

ECM -- A/C Relay Circuit Status: The scan tool displays OK/Open/Short/Invalid State. This represents the current state on the A/C compressor clutch relay control circuit.

ECM -- A/C Relay Command: The scan tool displays On/Off. The scan tool displays the control decision for the compressor clutch relay output as determined by the ECM.

ECM -- A/C Request Signal: The scan tool displays Yes/No. The scan tool displays Yes when the ECM receives a class 2 message from the body control module (BCM) to engage the A/C compressor clutch.

ECT Sensor: The scan tool displays -39 to 140°C (-38 to 284°F) . The voltage applied to the ECM input from the engine coolant temperature sensor is converted to a temperature value.