Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Notes On Display And Control Head
-- Climatronic Control Module -J255- A/C display and control head, removing and installing. Refer to DISPLAY AND CONTROL HEAD, REMOVING AND INSTALLING .
The Climatronic Control Module -J255- A/C display and control heads cannot currently be interchanged as usual; the component protection is in effect. The component protection (anti-theft protection) can only be canceled by entering specific vehicle data, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function
If a Climatronic Control Module -J255- A/C display and 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. Convenience functions can no longer be selected. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
When replacing a Climatronic Control Module -J255- A/C display and control head, pay attention to the exact allocation. Different versions for vehicles with the "Basis" A/C system version or the "Convenience" A/C system version, for vehicles with left-hand driver or right-hand drive; with or without buttons for seat heating and/or seat ventilation, etc.
The setting for the seat heating and ventilation is adjusted on the Climatronic Control Module -J255- A/C display and control head; this adjustment is transmitted to the Vehicle Electrical System Control Module -J519- via the Data Bus. The target temperatures for the different seat heating and seat ventilation settings are stored in the Vehicle Electrical System Control Module -J519-. Depending on the version of the Vehicle Electrical System Control Module -J519- and on the vehicle date of manufacture, the specified temperature for the seat heating and ventilation can be different with the same setting on the Climatronic Control Module -J255- A/C display and control head, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function (for the Vehicle Electrical System Control Module -J519-).
If a new Climatronic Control Module -J255- A/C display and control head was installed and basic setting was not performed, the A/C system regulation is limited and this is displayed in the DTC memory as a malfunction. After installing the Climatronic Control Module -J255- A/C display and control head, perform the basic setting for the A/C system according to specification, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
The Climatronic Control Module -J255- A/C display and control head buttons, display and knobs are illuminated by LEDs (the LEDs cannot be replaced).
The function and indicator lamps in the buttons and in the knobs cannot be replaced separately.
If the Instrument Panel Temperature Sensor -G56- measurement is incorrect, check the Climatronic Control Module -J255- A/C display and control head intake grille trim (it must not be closed) and the function of the Interior Temperature Sensor Fan -V42-, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
The selected functions are displayed when the function and indicator lamps in the various Climatronic Control Module -J255- A/C display and control head buttons, knobs or display fields light up.
Depending on the version of the Climatronic Control Module -J255- A/C display control head, the currently selected functions will appear only on the Multi Media Interface (MMI) display (on the "Basis" version) or on the Climatronic Control Module -J255- A/C display control head display and on the Multi Media Interface (MMI) display (MMI, on "Convenience" version). The duration of display can be adjusted via the Guided Fault Finding "Adaptation" function for the Climatronic Control Module -J255- A/C display and control head, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
If no malfunction is stored and the Climatronic Control Module -J255- A/C display and control head is not working, check the adaptation (the function may be switched off by adjusting the function). If necessary, reset the adaptations in all adaptation channels to the manufacturer setting, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
If there is a condition, where the heating or ventilation of the driver of passenger seat cannot be switched on, this will be stored as a malfunction in the Vehicle Electrical System Control Module -J519-, in the Memory Seat/Steering Column Adjustment Control Module -J136- or in Front Passenger Memory Seat Control Module -J521- (depending on the vehicle type and the vehicle equipment level). Currently no information is sent to the Climatronic Control Module -J255- A/C display and control head via the Data Bus system; the DTC memory must be read out in each control unit or in the Comfort System Central Control Module -J393-, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function. In the event of a complaint regarding seat heating or seat ventilation, first check the DTC memory of the control modules activating the seat heating and seat ventilation.
From MY 2010, this vehicle has a Start/Stop System for specific engines as optional equipment. On vehicles with Start/Stop system, the Climatronic Control Module -J255- display and control head prevents the Stop function depending on the setting. If, for example, "defrost" is selected, the stop function is not possible or will be interrupted and the engine will start. The same applies in the case of heating and cooling. The difference between the selected and actual temperature exceeds a certain value, using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Vehicles with the Start/Stop System have an additional coolant pump for the Stop function depending on the vehicle equipment level and on the version of the vehicle. Refer to, COOLANT SYSTEM/COOLANT and using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- On the Audi Q5, the Climatronic Control Module -J255- -A- display and control head has additional trim -B-.
As a replacement part, the trim piece -B- is supplied with a two-sided adhesive strip already installed -C-.
If the trim -B- is going to be reused when replacing the display and control unit, the Climatronic Control Module -J255- -A- is also reused. Remove the adhesive strip -C- from the trim -B-. Clean the adhesive surface on the trim -B- as described in the instructions which came with the adhesive strip. Affix to the trim piece -B- a strip (dimension: 204 mm x 10 mm) of the two-sided adhesive tape -C- with material strength approximately 1.2 mm (for example with adhesive tape D 438 515 A1.
At the start of production, this trim piece -B- is secured by clips -C- into the openings -D- in the Climatronic Control Module -J255- -A- display and control head. Later, the trim piece -B- was redesigned so that it can be secured by a suitable two-sided adhesive tape. The retaining tabs -F- are no longer on these trim pieces -B-.
Since the openings -D- and slits -E- are no longer being used, the trim piece -B- is only supplied as a replacement part in the version that is secured with two-sided adhesive tape on the Climatronic Control Module -J255- -A- display and control head.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.