GLC43 Harsh 1to2 2to3 3to4, jolting when accelerating from stop
Topic number

LI27.60-P-079083

Version

6

Function group

27.60 - Gearshift, control

Date

2/6/26

Validity

MODEL 254 with ENGINE M139 and TRANSMISSION
725.164

Reason for change

Clarified Remedy Software

Complaint
•
•
•

Harsh 1-2, 2-3, and/or 3-4 shift
Jerky shifting
Jolting when accelerating from stop

Cause
Insufficient software application causing elevated K81/K27/B05 fill time adaptations and elevated torque adaptations
for concerning shift.

Remedy
As of 1/28/2026 the resolution software has been released.
With this software update, the transmission will adapt less often during normal driving. This will reduce the frequency
of the customer experiencing the concern by ensuring the learned adaptation values stay within acceptable range for
longer.
Please ensure your Xentry machine is up to date with the latest Add Ons and continue with the following steps:
Note: ALL steps must be performed to rectify concern
1. Perform software update for VGS control unit (A 001 902 20 34)
2. Check transmission oil level and correct, if necessary (transmission oil temperature > 60 °C)
3. Perform Xentry Valve Flushing procedure at least 3x
4. Perform a standstill adaptation, then read out new EEPROM data
5. Perform driving adaptation(s) while adhering to the below parameters for at least 20-30 miles until the shift quality
improves.
Note: There is no menu in Xentry for this procedure. We recommend displaying the torque in the instrument cluster. If
all below parameters are met at the time the shift, a driving adaptation will automatically occur.

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© Copyright Mercedes-Benz AG

SAHARRY

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Harsh 1-2
Perform a driving adaptation of 4-5 (adapts K81 for the 1-2 shift)
Harsh 2-3
Perform a driving adaptation of 2-3 (adapts B05 directly)
Harsh 3-4
Perform a driving adaptation of 3-4 (adapts K27 directly)
- Level track (no incline/decline)
- Slippery drive program
- Display the torque in the instrument cluster: The torque must be between 100 and 250 Nm (about 184 ft lbs), preferably closer to the maximum torque
- Constant engine torque
- Engine speed below 2500 rpm
- Do not shift via paddle
If the vehicle returns and already has the updated software, please submit a TIPS case to the Powertraininbox and
ensure the following is included:
- Initial Quick Test w/ Freeze Frame Data
- VGS Control Unit Log
- Initial EEPROM (before any adaptations or Xentry procedures were performed)
- Detailed vehicle history of the complaint

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
Power transmission > Automatic transmission > Function > Poor shift quality

Parts
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© Copyright Mercedes-Benz AG

SAHARRY

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Part number

ES1 ES2 Designation

A 001 902 20 34

Quantity Note

New Software Part Number

EPC

1

X

Operation numbers/damage codes
Op. no.

Operation text

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© Copyright Mercedes-Benz AG

Time

SAHARRY

Damage
code

Note

2701245

Please refer to this TIPS document
in the dealer text

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