167 Air Conditioning System Leak
Topic number

LI83.30-P-077763

Version

23

Function group

83.30 - Air conditioning

Date

10/1/25

Validity

167

Reason for change

Remedy

Complaint
Customer concern of Air Conditioning not cooling.
*NOTE - Use of tracer DYE for leak checks is not approved. Only approved leak check procedures as per WIS are approved.

Cause
Possible refrigerant leak.

Remedy
Perform the following measures :
*Important* - Photo documentation requirement is no longer in effect as of 10/1/2025.
Remedy 1: Replace Evaporator
(Only applies to vehicles produced PRIOR to April 15, 2022 and has NOT had the evaporator replaced previously)

1.
2.

Ensure that the rest of the AC system has been thoroughly checked for leaks with forming gas as per WIS before condemning the evaporator.
If no other leaks are found, replace the evaporator

Note - *If the evaporator housing has been opened or the evaporator or housing has been tampered with, the claim
will be debited.
Remedy 2:
(Applies to all vehicles produced on or AFTER April 15, 2022 up to April 1, 2025)
1.

Ensure that the entire AC system has been thoroughly checked for leaks with forming gas as per WIS .

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2.
3.
4.
5.
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7.
8.
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If no leaks were found AND the system came in with no cooling/low charge, OR the evaporator is suspected of
leaking:
Replace ONLY the expansion valve bracket, seals, and bolts as supplied in kit A 167 832 47 00, in accordance
with the procedure outlined in WIS document AR83.30-P-5520ME.
IF THE PRODUCTION DATE IS BETWEEN JUNE 1, 2023 AND JULY 1, 2024, REPLACE THE DRYER AS
WELL. (NOT THE CONDENSER)
After, charge the system and perform a few drive cycles.
Recheck the vehicle for leaks.
If no leaks are found, the vehicle can be released.
If a minor leak is detected that is less than 50ppm, then perform the following steps:
If a leak is detected, fill the system with forming gas
Close all doors and windows for 10 minutes.
Vehicle off with no blower activation.
Open the driver's door and measure ppm detection as soon as the door is open and the sniffer goes into the vehicle.
If no leaks are measured, fill the system and release.

Remedy 3:
(Only applies to vehicles produced AFTER April 1, 2025) *TIPS Case Required if leak is found*
Ensure that the entire AC system has been thoroughly checked for leaks with forming gas as per WIS .
If any leaks are found, then open a TIPS case with the following:

1.
2.
3.
4.
5.
6.
7.

Initial Quick Test
Create a short video of the actual pressures via AC machine, showing the engine running, and hold a copy of
the VIN/RO in view as well.
OBS recording of XENTRY AC actual values of compressor request to be on and current value. (Instructions in
Attachments)
Video recording of the leak being found via sniffer at the R/F AC drain after removing the under dash panel if the
evaporator is suspected. (see attached videos)
If the evaporator is found to be leaking via sniffer, another video needs to be uploaded (or a continuation if only
making the video after checks), showing the expansion valve being checked for leaks.
If no leaks are found with the sniffer at the expansion valve, spray soapy water mix on the expansion valve and
check for leaks. Upload a video showing the spray test and VIN.
Open a TIPS case in the HV/LV inbox labeled "167 AC leak after April 1, 2025" with all attachments.

NOTE: (Applies to all 167's)

•
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Please see the list of WIS documents for forming gas leak check and recharging of the system.
Review PCTT 9/25 for forming gas best practices.
Review PCTT 5/25 for bracket removal best practices.
Condenser replacement is NOT authorized as a suitable repair in lieu of the dryer not being available.
Ensure that the correct damage code is used for failed component. (see list of damage codes)
Evaporator housings that have been disassembled, present with physical damage, or tags that show signs of
tampering will be debited in full.

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Attachments
File

Description

Expansion valve leak.mkv
Leak at drain hose.mkv
Using OBS Studio For Xentry Kits.pptx

WIS-References
Document number

Title

Note

AR83.30-P-1760ME

Drain, evacuate and recharge air con- Performing drain and refill
ditioning, check for proper operation
and check for leaks

AR83.30-P-1761ME

Check air conditioning system for lea- Must be done for all leak checks
kage

AR83.30-P-1785ME

Flush air conditioning

Only to be performed if debris is found
in the system

SI83.30-P-0021A

Service Information: Damage code

Notes for damage code to be used.

Disclaimer
NOTE: The information contained in this document is intended for use by trained, professional technicians with the
knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz
approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and
provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect
is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a
symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes
resulting in the same or similar symptoms or conditions described in this document, and trained professional service
technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained
in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

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

Operation numbers/damage codes
Op. no.

Operation text

Time

Damage
code

Dryer desiccant cartridge

H

8350C7

Condenser

H

834370

Evaporator Damage Code

H

8343204

Expansion valve

H

834314

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Note

Use this for the expansion valve bracket

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