Hello iatn Fellows:

A Volkswagen Passat 2010 came with the following problem with its Automatic Klimatronic. It cools badly, sometimes improve a little and sometimes goes bad again. Scanned and no code present. Connected the oscilloscope to the signal wire of the solenoid valve and the signal is showing the system wants to enlarge the displacement (maximum positive pulse width) The low pressure is 62 psi and high pressure 165 psi idling and at 2000 rpm the low pressure goes down a little and after 5 seconds goes up again to the same value and no change in high pressure value. Very high ambient temperature, 36 degree. I think that the cause is the compressor or perhaps it is the solenoid valve. I really do not know how I can realize if it is the compressor or just the solenoid valve. I didn't attempt to add refrigerant because of its high low pressure. You can see the picture of the signal. Perhaps some of you can give me some advise. Thank you very much. Francisco

Diego Gaynor
Educator/Instructor
Cise Electronics
Buenos Aires, Argentina