Test Requirements

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.

• Clean radiator and condenser (clean if necessary).

• 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.

• DTC memory of Climatronic Control Module (J255). was checked and erased, basic setting was performed using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• The Climatronic Control Module coding has been checked using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• The Climatronic Control Module adaptation has been checked using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

Adjustments on vehicle

- Open all instrument panel vents.

- Close hood.

- Set operating mode "Auto" on Climatronic Control Module (J255).

- Set temperature preselect for driver and front passenger side to "Lo" on Climatronic Control Module (J255).

Functions with engine running

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

• The air conditioner goes in recirculating air mode (approximately 1 minute after starting the engine), the fresh air intake is closed and the recirculating air intake opens ( Fresh air blower (V2) extracts the air from passenger compartment below instrument panel / glove compartment).

• The Coolant fans (V7) run (activation and speed depends on pressure in refrigerant circuit and on the engine temperature).

• Depending on version of Climatronic Control Module (J255) , Coolant Fan (V7) is switched on immediately or only from a certain pressure in refrigerant circuit (from a pressure of 9 bar at this time). The actuation of the A/C compressor regulator valve (N280) is displayed in the vehicle electrical system control module measured values block using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• If one of these test requirements is not fulfilled, perform Guided Fault Finding using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.