Cooling Performance Test Requirements

Cooling Performance Test Requirements

Special tools, testers and auxiliary items required

• Vehicle diagnosis, testing and information system (VAS5051B) (or Vehicle Diagnosis and Service System (VAS 5052) ).

• A standard thermometer (for temperature measurements, if necessary a thermometer with 2 measuring probes for simultaneous measurement e.g. for temperature on the right and left)

• Ambient temperature greater than 15 °C

• Radiator and condenser are clean (if necessary clean)

• The ribbed belt, which drives the A/C compressor, is OK and is tensioned correctly. The ribbed belt is actually driving the A/C compressor.

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

• Air flow through dust and pollen filter not obstructed by dirt.

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

• Vehicle not exposed to sunlight

• Engine is warm

• Climatronic control module (J255) DTC memory was checked and erased, basic setting was performed and Climatronic control module coding was checked. Refer to (VAS5051B) under "Guided Fault Finding."

• The Climatronic control module was checked using (VAS5051B) under "Guided Fault Finding."

• All instrument panel vents open

• The hood is closed.

• Settings on Climatronic control module:

- "Auto" operating mode (indicator light on the AUTO button lights up).

- Turn the temperature rotary switch to "cold"

- The A/C compressor is on (the indicator lamp on the AC button comes on).

- Fresh air blower rotary switch in "maximum speed" stop.

• 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 radiator fans (coolant fan and coolant fan 2) are only switched on at a certain pressure in the coolant circuit (currently, at a pressure of approximately 9 bar). The radiator fan(s) control is displayed in the measured values block using (VAS5051B) under "Guided Fault Finding."

- Fresh Air Blower (V2) runs at maximum speed.

- The air conditioner goes in recirculation mode (approximately 1 minute after starting the vehicle, the back pressure/fresh air door is closed and the recirculation door is opened, Fresh Air Blower (V2) extracts the air from passenger compartment below instrument panel / glove compartment).

• If one of these test requirements is not fulfilled, check the DTC memory, perform a final control diagnosis and read the measured values block using (VAS5051B) under "Guided Fault Finding."