Test Requirements

• Ambient temperature greater than 15 °C (59 °F).
• Radiator and condenser are clean (clean if necessary).
• The ribbed belt, which drives the A/C compressor, is OK and tensioned correctly. The belt pulley is actually driving the A/C compressor (vehicles without a high-voltage system).
• All air ducts, covers and seals are OK and properly installed.
• Seal between the engine compartment, hood and plenum chamber is OK and installed correctly. Refer to BULKHEAD ; (Overview - Plenum Chamber Cover) to check.
• The airflow through the dust and pollen filter is not obstructed by debris. Refer to DUST AND POLLEN FILTER, REMOVING AND INSTALLING to check.
• The heater and A/C unit air intake (in fresh air and recirculating air modes) is not obstructed by dirt or retrofitted components.
• Vehicles without glove compartment cooling: glove compartment cooling connection is sealed on the A/C unit.
• Vehicles with glove compartment cooling: glove compartment cooling connection is installed on the A/C unit according to the specification.
• The vehicle is not exposed to sunlight.
• Engine is warm; coolant temperature is greater than 80 °C (176 °F).

• The DTC memory for the A/C Control Module -J301- /Climatronic Control Module -J255- control head was checked and erased, the basic setting performed and the A/C Control Module -J301- /Climatronic Control Module -J255- coding checked using the Vehicle Diagnostic Tester in the "Guided Fault Finding  " function.
• A/C Control Module -J301- /Climatronic Control Module -J255- adaptation checked using the Vehicle Diagnostic Tester in the "Guided Fault Finding  " function.
• All instrument panel vents and, if present, vents in the rear center console are opened.
• Check that the air outlet from the rear footwell vents (under the front seats) is not blocked by the floor mats or other objects.
• Front lid closed.

On Vehicles with a High-Voltage System (Hybrid Vehicles) 

• The ignition is switched on and the ready mode is activated (note the display in the instrument cluster), the engine starts or only runs, for example, when the High-Voltage Battery 1 -AX2- is not charged enough or the hood is unlocked. Refer to the Owner's Manual.
• With the ignition switched on and the temperature preset "warm" on the Climatronic Control Module -J255- A/C control head ("HI" in the display), the coolant flow through the heater and A/C unit heater core is maintained via the High Temperature Circuit Coolant Pump -V467-. Refer to High-Voltage Heater (PTC) -Z115-, INCORPORATION IN COOLANT CIRCUIT and OVERVIEW - COOLANT PUMP/THERMOSTAT .

-- Switch the ignition on.

-- Move the selector lever into position P.

-- Activate the parking brake.

-- Switch off the ignition.

-- Open the hood.

-- Connect the charger, for example Battery Charger :VAS5095A  , to the jump start point for the 12V vehicle electrical system

-- Switch the ignition on.

-- Activate the ready mode (the engine does not need to start at first).

Vehicles without High-Voltage System 

-- Start the engine.

-- The engine runs (if necessary, change the setting on the A/C Control Module -J301- or the Climatronic Control Module -J255- control head in the direction "heat").

Vehicles with Manual Climate Control System: 

Fig 1: Identifying Display And Control Unit, Electric Manual Climate Control System

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Adjust the following settings on the A/C Control Module -J301- control head: 

• Turn the temperature setting regulator -11- to the "cold" stop.
• A/C compressor on: The indicator lamp in the A/C  button -2- illuminates.
• Recirculating air mode on: the indicator lamp in the recirculation  button -4- illuminates.
• Turn the air distribution regulator -7- to the "instrument panel vent" stop.
• Turn the fresh air blower regulator -9- to the maximum speed.

Vehicles with Automatic Climate Control System (with and without a High-Voltage System): 

Fig 2: Display Control Head, Climatronic

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Adjust the following settings on the Climatronic Control Module -J255- control head: 

• "Auto" mode: the indicator lamp in the AUTO  button -14- illuminates.
• Set the temperature preset "cold" via the regulators -21 and 11- : "LO" for the driver and front passenger side in the display -1 and 8- of the Climatronic Control Module -J255-.
• A/C compressor on: The indicator lamp in the A/C  button -10- illuminates.
• Turn the fresh air blower regulator -16- to the maximum speed.

Continuation for All Vehicles: 

Functions with the engine running (on vehicles without a high-voltage system): 

Functions with ready mode activated (on vehicles with a high-voltage system): 

• The Radiator Fan -V7- /Radiator Fan 2 -V177- run. The activation and speed depend on the pressure in the refrigerant circuit and the engine temperature.

• The fresh air blower runs at maximum speed.

• The A/C system goes into recirculating air mode. Approximately one minute after starting the engine (activating the ready mode), the back pressure/fresh air door is closed and the recirculation door is opened. The fresh air blower extracts the air from passenger compartment below instrument panel / behind the glove compartment.

If one of these requirements is not met: 

-- Check the DTC memory, perform an output diagnostic test and read the measured values using the Vehicle Diagnostic Tester in the "Guided Fault Finding  " function.

Continuation: 

Refer to COOLING OUTPUT, CHECKING, VEHICLES WITH MANUAL CLIMATE CONTROL SYSTEM 

Refer to COOLING OUTPUT, CHECKING, VEHICLES WITH AUTOMATIC CLIMATE CONTROL SYSTEM (WITHOUT HIGH-VOLTAGE SYSTEM) 

Refer to COOLING OUTPUT, CHECKING, VEHICLES WITH AUTOMATIC CLIMATE CONTROL SYSTEM (WITH HIGH-VOLTAGE SYSTEM)