audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

ABOUT US
Checking pressures > < Checking pressures in refrigerant circuit with air conditioner service station (with ignition switched off)

A2

Test requirements
Test requirements
l  Radiator and condenser clean (clean if necessary)
l  Thermal insulation at expansion valve OK and properly installed.*
l  The ribbed belt is OK and properly tensioned. / belts for air conditioner compressor and alternator OK and properly tensioned.*
l  All air ducts, covers and seals OK and properly installed.
l  Electrical system and vacuum system fault finding has not revealed any faults* → Vehicle diagnostic tester („self-diagnosis“ or „Guided Fault Finding“ function for air conditioner) and → Heating, air conditioning; Rep. gr.87 or → Air conditioning; Rep. gr.87 (vehicle-specific workshop manual).
l  Air conditioner self-diagnosis has not revealed any faults (with engine running and air conditioner switched on), no compressor shut-off criteria displayed in measured value block (vehicles with „air conditioner“ self-diagnosis only) * → Vehicle diagnostic tester („self-diagnosis“ or „Guided Fault Finding“ function for air conditioner) and → Heating, air conditioning; Rep. gr.87 or → Air conditioning; Rep. gr.87 (vehicle-specific workshop manual).
l  Air flow through dust and pollen filter not impeded by dirt*
l  Air conditioning unit not drawing in secondary air at maximum fresh-air blower speed; evaporator and heater not drawing in secondary air at maximum fresh-air blower speed*
l  Air flaps in air conditioning unit, heater and evaporator reach end position*
l  Fresh-air intake ducts beneath bonnet and in passenger compartment as well as corresponding water drain valves OK* → Heating, air conditioning; Rep. gr.87 or → Air conditioning; Rep. gr.87 (vehicle-specific workshop manual).
l  Engine at operating temperature
l  Vehicle not exposed to sunlight → Heating, air conditioning; Rep. gr.87 or → Air conditioning; Rep. gr.87 (vehicle-specific workshop manual).
l  Ambient temperature above 15 ° C
l  All dash panel vents open.
–  Start engine.
Setting at the operating and display unit for Climatronic air conditioning system -E87- or the Climatronic control unit -J255- (and the rear Climatronic operating and display unit -E265- on vehicles with two air conditioner units):
–  Preselect „Auto“ mode (air conditioner compressor on).
–  Set „LO“ temperature for driver's and front passenger's side (and rear left and right on vehicles with two air conditioner units).
Settings on heater controls:
–  Press A/C button and "Rec" or air recirculation button.
–  Turn the rotary temperature control towards the „cold“ stop.
–  Set rotary fresh-air blower control to „4“.
Subsequently, the following system test requirements should be met:
l  Operation of radiator fan(s) -V7- (at least speed 1).*
  Note
With some versions, the fan is not switched on until the pressure in the refrigerant circuit has exceeded a specified value.
l  Fresh air blower -V2- (and rear fresh air blower -V80- on vehicles with two air conditioning units) run(s) at maximum speed.
l  Recirculated/fresh-air flap set to „Recirculated air mode“ (within 1 min. after starting vehicle, air-flow flap is closed and recirculated-air flap opened)*
l  Coolant shut-off valve closed.*
l  Valves of pump valve unit closed and no coolant circulation pump delivery.*
l  Air conditioner compressor is actually driven (air conditioning system magnetic clutch -N25- energised, overload safeguard (if fitted) not tripped).*
  Note
Depending on the engine, the air conditioner compressor is driven by different components (belt or drive shaft). To protect these components and the engine, the pulley or the air conditioner compressor drive unit is fitted with an overload safeguard which is tripped if the air conditioner compressor is not operating smoothly → Heating, air conditioning; Rep. gr.87 or → Air conditioning; Rep. gr.87 (vehicle-specific workshop manual).
   

Checking pressures > < Checking pressures in refrigerant circuit with air conditioner service station (with ignition switched off)