Audi A4: Refrigerant Circuit Complaints
Possible Refrigerant Circuit Concerns
Test Requirements
- Electrical Equipment, vacuum system and air duct
fault-finding has not revealed any faults. Refer to Guided Fault
Finding for the A/C system ("OBD" or "Guided Fault Finding for
the A/C system"),
→ Wiring diagrams, Troubleshooting & Component locations.
- The OBD/Guided Fault Finding for the A/C System with Vehicle
Diagnostic Tester cannot detect a fault, the A/C compressor shut
off condition is not displayed in the measured values block
(only on vehicles with OBD "A/C System"). Refer to "Guided Fault
Finding".
Possible Concerns
Note
- For all complaints marked.
- 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
→ Chapter "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-, A/C Pressure Switch -F129-
or by the Front A/C Display Control Head -E87- or Climatronic
Control Module -J255-) due to excessive or inadequate pressure
*. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - 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
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - 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
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - 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 theVehicle 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).
READ NEXT:
Vehicles with a High Voltage System (Hybrid Vehicles)
Extremely Dangerous Due to High-Voltage
The high-voltage system is under high-voltage. Death or serious
bodily injury by electric shock.
- I
Servicing Station, Connecting for Measuring and Testing
- Turn off the ignition.
- Connect the service station to the power supply.
- Connect the quick-release coupling adapter to the c
SEE MORE:
Overview - Front Lid
Overview - Hood
1 -
Adjusting Buffer
Adjusting. Refer to
→ Chapter "Height, Adjusting using Adjusting Buffer".
2 -
Striker
Removing and installing. Refer to
→ Chapter "Striker, Removing and Installing".
Adjusting. Refer to
→ Chap
Front Storage Compartment, Removing and Installing
Removing
- Remove the center console insert. Refer to
→ Chapter "Center Console Insert, Removing and Installing".
- Remove the storage compartment -1-
from the center console toward the rear in the direction of
-arrows-.
- Di