Possible Concerns

WARNING: This page is about a different car, the 2021 Audi S4 and 2021 Audi A4 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
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 .
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 .
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).