Complaint
Insufficient cooling capacity and/or noises from refrigerant compressor
Cause
Under analysis
Remedy
In order to detect the fault, please perform the following test steps:
1. Connect manometer of air conditioning service unit in order to read off high pressure and low pressure
2. Connect XENTRY and bring up all climate control actual values in air conditioning menu under "actual values"
3. Set blower to speed 7
4. Set temperature on both sides (driver and front passenger) to LOW
5. Activate AC ON
Result 1: Only a small pressure ratio is established (e.g high pressure 7-8 bar; low pressure 5-6 bar). Continue with
step (A)
Result 2: A larger pressure ratio is established (e.g high pressure 12-16 bar; low pressure 0-2 bar). Continue with step
(B)
(A): Check the dryer package for black oil and particles.
(A.1) Black oil and particles present: Replace refrigerant compressor and valves, flush refrigerant circuit according
to instructions in WIS (Refrigerant-only flushing method). Then put system into operation. If the high pressure and
low pressure values are OK and the system functions as intended, the vehicle can be returned to the customer. If the
pressure ratio is still not correct, continue with step (C)
(A.2) No black oil or particles present: continue with step (B)
(B): Disconnect vehicle-side power supply for shutoff valve Y19/3 and externally power shutoff valve Y19/3 with 12 V.
With the blower setting still set to speed 7, allow the air conditioning system to run. Measure the low pressure while
this occurs.
