A/C System

A/C System

DANGER!
Before working on electrical system, remove relevant fuse(s)

• Refer to Vehicle Diagnosis, Testing and Information System (VAS 5051 A) via the "Guided Fault Finding " function Vehicle Diagnosis, Testing and Information System VAS5051 in "Guided Fault Finding" function.

• Applicable wiring diagrams can be found in Electrical Wiring Diagrams.

• A data plate in engine compartment indicates the refrigerant used and capacity.

• Before performing electric welding on the vehicle, disconnect battery.

Refrigerant circuit of A/C system must not be discharged and opened. Refer to => [ Draining Refrigerant Circuit ] Draining Refrigerant Circuit. Unless this is necessary because of safety precautions. Refer to => [ Servicing Refrigerant Circuit ] Servicing Refrigerant Circuit or unless components of the refrigerant circuit of the A/C system have to be to replaced.

When performing all other usual vehicle repair work, the refrigerant circuit of the A/C system should remain closed.

Servicing operations that can be performed on the heating and air conditioning system without opening the refrigerant circuit are described in this Repair Manual. Refer to => [ Servicing Refrigerant Circuit ] Servicing Refrigerant Circuit.

• The connections for the senders/switches described in this Workshop Manual are fitted with a valve which closes automatically when the switches are unscrewed. These switches can thus be replaced in any Audi and Volkswagen workshop even though the refrigerant circuit is fully charged.

This repair manual also describes service procedures that require the refrigerant circuit to be emptied, even though they cannot be performed in every Audi or VW workshop. Refer to => [ Servicing Refrigerant Circuit ] Servicing Refrigerant Circuit to drain the refrigerant circuit, bring the vehicle to a workshop that has the necessary tools and qualified personnel.

A/C System OBD Information

• Climatronic Control Module and Rear A/C Control Head Climatronic are available in different versions. Pay attention to precise assignment on replacement.

• A/C system OBD is performed in the "Guided Fault Finding" function with the Vehicle Diagnosis, Testing And Information System (VAS 5051 A) Vehicle diagnosis, testing and information system in the "Guided Fault Finding" function.

• Front A/C control heads can no longer be cross-exchanged in the familiar way; as soon as a front A/C control head, the Climatronic Control Module (J255) has been adapted in a vehicle, the component protection takes effect. Component protection can only be canceled by entering specific vehicle data Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

• If a climatronic control module front A/C control head with active component protection anti-theft system is installed in a different vehicle, only the functions necessary for vehicle safety can be selected. Comfort functions cannot be selected Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• If a Climatronic Control Module (J255) front A/C control head or Rear A/C Control Head (Climatronic) (E265)) is to be replaced, check the coding (Climatronic Control Module (J255) front A/C control head) and adaptation front Climatronic Control Module (J255) and Rear A/C Control Head (Climatronic) (E265) before removing with the "Replace control module" function of Guided Fault Finding for this control head Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• The function "electrical testing" is not described in this Repair Manual. Perform the electronic test with the "Guided Fault Finding" function. This also contains information on the functions that should be tested. Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• The temperature-dependent resistance values for the various temperature sensors are in the table. They can be accessed with the "Guided Fault Finding" function. Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• Pressing and holding the buttons on the Climatronic Control Module (J255)front A/C control head or Rear A/C Display Control Head (E265) for an extended period of time. For an example setting an object down on them can cause an entry in the DTC memory due to stuck buttons. If necessary, check the function of the buttons and erase the DTC memory if no malfunction is found.

• When OBD is started, the control modules which are activated by the front A/C control head, Climatronic Control Module (J255) / Rear A/C Control Head (Climatronic) (E265) are indicated,. Driver's Seat Ventilation Control Module (J672), Heated Windshield Control Module (J505), etc. (depending on vehicle equipment).

• From model year 2009, the Climatronic Control Module (J255) front A/C control head with part number 4E0 820 043 from index "J" will be installed as a running change. On vehicles with these front A/C control heads, the screen in the "MMI" display will not switch to "A/C system" when the buttons and knobs on the front A/C control head are pressed. The selected A/C system functions are shown in the running display. Certain A/C system functions in these vehicles will be selected and activated with the rotary push buttons on the "MMI" unit => Owner's Manual and => " Infotainment/MMI" Owner's Manual. On these front A/C control heads, the Setup button is replaced with the A/C button and the ON /OFF button is replaced with the OFF button => Owner's Manual.

• Make sure the Climatronic Control Module (J255) front A/C control head is allocated correctly to the Information Electronics Control Module 1 (J794) different versions. If the allocation is incorrect, various A/C system functions cannot be displayed and selected in the MMI.

• The engine type is coded with a Climatronic Control Module (J255) front A/C control head from software version " X078". With an FSI engine, the gear ratio to the belt pulleys and thus the torque for the compressor drive is different from other engines. Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• The layout and display of various display groups is different between the Rear A/C Display Control Heads (Climatronic) (E265) that were installed through November 2002 and those installed from November 2002. Certain display groups are not used in the version installed from November 2002 Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

A/C System Component Electrical Test

• The "electrical testing" function is not described in this repair manual. Perform the electronic test with the "Guided Fault Finding" function. This also contains information on the functions that should be tested Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.

• The temperature-dependent resistance values for the various temperature sensors are in the table. They can be accessed with the "Guided Fault Finding" function Vehicle diagnosis, testing and information system VAS 5051 in "Guided Fault Finding" function.