Possible Concerns

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Audi S6, 2018 Audi A6 Quattro, 2018 Audi A6, 2017 Audi S6, and 2017 Audi A6 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

For all complaints marked *. Refer to PRESSURES, CHECKING "Checking pressures".

If a malfunction occurs at only one evaporator in vehicles with two evaporators, also check the pressures in the refrigerant circuit.

Observe the test requirements. Refer to TEST REQUIREMENTS .

Vehicles without a High-Voltage System

Total cooling system failure *
Insufficient cooling output at all vehicles speeds or engine speeds *
None or insufficient cooling after driving a few miles *
No or insufficient cooling at one or both evaporators (for vehicles with two A/C units) *
The A/C compressor, A/C Clutch -N25- or A/C Compressor Regulator Valve -N280- are shut off by a pressure switch (for example, A/C Refrigerant Low Pressure Switch -F73-, Magnetic Clutch High Pressure Switch -F118- or by the Front A/C Display Control Head -E87- or Climatronic Control Module -J255-) due to excessive or inadequate pressure *. Refer to REFRIGERANT CIRCUIT [For engine(s) CTUA, CAED, CREH, CEUC, CTGE, CREC, CYNB, CPNB]
None or sharp decrease in fresh-air supply after driving several miles (evaporator iced up) *

Vehicles with a High-Voltage System

Total cooling system failure *
Insufficient cooling output at all vehicles speeds or A/C compressor speeds *
None or insufficient cooling after driving a few miles. *
No or insufficient cooling in the evaporator or on a heat exchanger (for example on the high-voltage battery heat exchanger) *. Refer to REFRIGERANT CIRCUIT [For engine(s) CTUA, CAED, CREH, CEUC, CTGE, CREC, CYNB, CPNB] .
No or insufficient heating output on the heat exchanger for the heat pump output (for example on the Audi Q7 e-tron) *. Refer to REFRIGERANT CIRCUIT [For engine(s) CTUA, CAED, CREH, CEUC, CTGE, CREC, CYNB, CPNB] .
The Electrical A/C Compressor -V470- is switched off by a control module (for example Front A/C Display Control Head -E87-, Climatronic Control Module -J255- or Thermal Management Control Module -J1024-) due to excessive or inadequate pressure. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function
None or sharp decrease in fresh-air supply after driving several miles (evaporator iced up). *

All Vehicles

From these, the following complaints may also occur:

The A/C Compressor Makes Noises

-- Tighten compressor securing bolts and compressor bracket using a torque wrench.

-- Check the routing of refrigerant lines; they must not touch other components and must not be subject to strain (align if necessary).

Noise (Refrigerant Hammer) Occurring Immediately after Switching on Air Conditioner and/or When Cornering or Braking

-- Discharge, evacuate and charge refrigerant circuit (too much refrigerant in circuit).

NOTE:

Too much refrigerant oil in the circuit could also cause this problem. This could occur if the amount of refrigerant oil was not adjusted when replacing the A/C compressor.

Water Sprays out of Vents (in Dash Panel or Footwell) Although Air Conditioning System is Otherwise Functioning Properly:

-- Check proper routing of condensate drain; it must not be crushed or kinked.

-- Check condensation drain valve, it must not be clogged by wax or underbody sealant and must close properly.

-- Check plenum chamber cover; it must not be damaged and must be properly installed (to stop water running into evaporator).

-- Check the water drains in plenum chamber; they must not be blocked (for example, by leaves).