Testing Requirements For Heating Output And Activation Of A/C System Temperature Control Doors

• The engine coolant circuit must be bled according to the instructions. Refer to COOLANT, DRAINING AND FILLING
• The engine must be warm (the coolant temperature is higher than 80 °C (176 °F).
• All air ducts, covers and seals are OK and properly installed.
• If a vehicle has electric radiator shutters, their function is OK.
• The airflow through the dust and pollen filter is not affected by dirt in the filter. Refer to DUST AND POLLEN FILTER, REMOVING AND INSTALLING .
• The air intake for the front heater and A/C unit (in fresh air and recirculating air mode) is not impaired by contamination or retrofitted components.
• Make sure that the air vent from the rear footwell vents (under the front seats) is not blocked by the floor mats or other objects.
• The integration of the heater core in the heater and A/C unit corresponds to the specifications. Coolant hoses must not be crushed or incorrectly connected. Refer to HEATING AND A/C SYSTEM, INTEGRATING IN ENGINE COOLANT CIRCUIT
• The vehicle is not exposed to sunlight.
• The DTC memory of the Front A/C Display Control Head -E87- and the Rear A/C Display Control Head -E265- or the Vehicle Electrical System Control Module -J519- are called up and the malfunctions present are fixed. Use the Vehicle Diagnostic Tester.
• The following must be set for A/C system control: auto air recirculation "off" and footwell temperature to "medium". Refer to Owner's Manual.
• All instrument panel vents, the B-pillar vents, and the vents in the rear center console are open.
• The hood is closed.
• The type of auxiliary heating depends on the vehicle equipment level.
• If there is a complaint regarding insufficient heating output at low exterior temperatures on vehicles with a gasoline engine and "parking heater" optional equipment, check the settings in the MMI for activating the parking heater as an auxiliary heater and the activation and function of the parking heater as an auxiliary heater. Refer to the appropriate service information (depending on the vehicle equipment).
• If there is a complaint regarding insufficient heating output at low exterior temperatures in vehicles with a diesel engine, check the settings in the MMI for the auxiliary heater and the activation and function of the auxiliary heater. Refer to Vehicle Diagnostic Tester or the appropriate service information (depending on the vehicle equipment).
• Certain A/C system functions can be switched on and off via the MMI (Multi Media Interface) in the "A/C system" function under the "Car" / "Vehicle" menu. The A/C system control can also be influenced via the presets in the MMI (Multi Media Interface) under the "A/C system" function in the "Car" / "Vehicle" menu. Therefore, check the preset in the MMI first in case there is a concern regarding these components. Refer to Owner's Manual.

Also on vehicles with a high-voltage system (Audi Q7 e-tron)

• The activation of the A/C system in the function "heat pump is OK". Refer to HEATING PUMP FUNCTION, CHECKING THROUGH A/C SYSTEM, ONLY ON VEHICLES WITH HIGH-VOLTAGE SYSTEM .
• No errors are stored in the Thermal Management Control Module -J1024- and the function of the components controlled by the Thermal Management Control Module -J1024- is OK. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding  " function.

If the above mentioned requirements are fulfilled:

• Heating output, checking. Refer to A/C SYSTEM HEATING OUTPUT AND TEMPERATURE CONTROL DOOR ACTIVATION, CHECKING .