Insufficient Cooling Capacity and/or Compressor Noises
Topic number

LI83.30-P-073900

Version

1

Function group

83.30 - Air conditioning

Date

12/9/21

Validity

253 hybrids (code ME05 to ME10)

Reason for change

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.
2.
3.
4.
5.

Connect manometer of air conditioning service unit in order to read off high pressure and low pressure
Connect XENTRY and bring up all climate control actual values in air conditioning menu under "actual values"
Set blower to speed 7
Set temperature on both sides (driver and front passenger) to LOW
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.
09.12.2021 19:42:22
© Copyright Mercedes-Benz AG

JKANTAR

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(B.1) The low pressure goes toward = 2bar: continue with step (C)
(C): Create a PTSS case with the following information:
1.
2.
3.
4.

Compare pressure values of manometer and XENTRY sensor values
Attach additional XENTRY values that describe the problem to the TIPS case
Qualitative video of the problem
Attach all data arising from step (A) and/or (B) to the TIPS case

Attachments
File

Description

Label Check vom Absperrventil Y19_3.JPG

Instruction for taking pictures of shutoff valve Y19/3

Symptoms
Body > Air conditioning > Air conditioning > Insufficient cooling output
Body > Air conditioning > Air conditioning > Noise

Operation numbers/damage codes
Op. no.

Operation text

09.12.2021 19:42:22
© Copyright Mercedes-Benz AG

Time

Damage
code

Note

ZM

8350C

Please only use SSL for the application of step (A)

ZM

8310M

Please only use SSL for the application of step (B)

JKANTAR

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