A/C Cooling Output, Testing Requirements

A/C Cooling Output, Testing Requirements

• Ambient temperature greater than 15 °C (60° F).

• Radiator and condenser are clean (if necessary clean).

• The ribbed belt for the A/C compressor drive is OK and correctly tensioned, and the belt pulley actually drives the A/C compressor (in vehicles with a 6 cylinder engine or 12 cylinder engine) => [ A/C Compressor Belt Pulley ] Service and Repair.

• The A/C compressor drive unit is mounted correctly, and the A/C compressor is actually driven (in vehicles with an 8 cylinder FSI engine), refer to => [ A/C Compressor Drive Unit ] A/C Compressor Drive Unit.

• All air ducts, covers and seals OK and properly installed

• Air flow through dust and pollen filter not obstructed by dirt, refer to => [ Dust and Pollen Filter ] Service and Repair.

• Air intake apparatus (in fresh air and recirculating air mode) is not impaired by soiling or components installed as retrofit.

• The air duct for glove compartment cooling is installed in the glove compartment as specified, refer to => [ Air Duct For Glove Compartment Cooling ] Air Duct For Glove Compartment Cooling.

• Vehicle not exposed to sunlight

• The engine is warm (the coolant temperature is higher than 80 °C (176° F).

• The event memory of the Climatronic control module (J255) (and the rear A/C display control head (E265) if present) was checked and erased, the basic setting was performed, and the coding of the Climatronic control module (and the rear A/C display control head) was checked using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• The adaptation of the Climatronic control module (and the rear A/C display control head if present) was checked using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• The following is set in the MMI (Multi Media Interface) via the "A/C system" function in the "car"/"car systems" menu for the regulation of the A/C system: automatic recirculation off, air flow center and footwell temperature medium (arrow pointing up).

• The various functions for the adjustment of the A/C system in the MMI (Multi Media Interface) (function "A/C" in the "Car" / "Car-System" menu) differ depending on the A/C system version, on the time period of production and on the vehicle version (may not be available for all versions). Refer to the Owner's manual.

• For USA market version vehicles, after a specific date of manufacture, specific settings for the A/C system via the MMI are no longer planned (for example the "Air still" function). Refer to the Owner's manual. Also pay attention to the coding and adaptation of the Climatronic control module (J255) front A/C display and control head. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• All instrument panel vents and the vents in the rear center console and in the B-pillar are open.

• The vent for glove compartment cooling (in the glove compartment) is closed.

• Ensure that the air outlet from the rear footwell vents (under the front seat) is not blocked by floor mats or other objects.

• The hood is closed.

• The engine is running.

Set the following on the Climatronic control module:

• Auto mode (the indicator lamps in both AUTO buttons illuminate).

• Temperature preselection cold for the driver and front passenger side (display LO for the driver and front passenger side in the Climatronic control module display and in the Multi Media Interface display).

• The A/C compressor is switched on (the indicator lamp in the AC button of the Climatronic control module illuminates).

• Preselection for the fresh air blower (V2) (and the rear fresh air blower) maximum speed (shown in the display of the Climatronic control module and in the display of the Multi Media Interface speed 10 or higher).

Set the following on the rear A/C display control head if present:

• Auto mode (the indicator lamps in both AUTO buttons illuminate).

• Temperature preselection cold (display LO for the left and right sides).

• Preselection for the rear fresh air blower maximum speed.

• For vehicles where there is also the version with the rear air distribution housing, there is a rear Climatronic A/C display control head (E265) installed. The air temperature and the air volume calculated and regulated by the Climatronic control module (J255) is also influenced by the setting on the rear Climatronic A/C display control head. However, only the temperature is adjustable for this rear Climatronic A/C display control head and there is only an AUTO button, refer to => [ Rear A/C Control Head (E265) ] Rear A/C Control Head (E265).

• The indicator lamps in the AUTO buttons go out when the fresh air blower speed is changed manually.

• The maximum possible fresh air blower speed depends on several conditions (coolant temperature, vehicle voltage, etc.)

Functions with engine running:

- The radiator fan ( coolant fan (V7) and coolant fan 2 (V177) ) run (activation and speed depend on pressure in coolant circuit and engine temperature).

• Depending on the version of the Climatronic control module, the coolant fan(s) (coolant fan and coolant fan 2) are only switched on starting at a certain pressure in the coolant circuit (currently starting at a pressure of approximately 9 bar). The activation of the coolant fan(s) is displayed in the read measured values function of the Guided Fault Finding using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function

- The fresh air blower (V2) runs with maximum speed (10 or greater).

- The rear fresh air blower (V80) runs at maximum speed.

• The maximum possible fresh air blower speed depends on several conditions (coolant temperature, vehicle voltage, etc.)

- The front A/C system switches to recirculation mode (approximately 1 minute after starting the engine, 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 event memory, perform the output diagnostic test mode and read out the relevant measured values using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function