Service bulletin LI27.19-P-080823
Manufacturer communication, from NHTSA Manufacturer Communications
- Published by NHTSA
- Aug 31, 2026
- Manufacturer
- MERCEDES-BENZ
- NHTSA ID
- 11036514
- NHTSA category
- Service Bulletin/Repair Instructions
- Applies to, as stated by NHTSA
- MERCEDES-BENZ A 220 2021-2022; MERCEDES-BENZ A 220 4MATIC 2021-2022; MERCEDES-BENZ AMG A35 2021; MERCEDES-BENZ AMG CLA35 2021-2023; MERCEDES-BENZ AMG CLA45 2021-2023; MERCEDES-BENZ AMG GLA35 2021-2023; MERCEDES-BENZ AMG GLA45 2021-2023; MERCEDES-BENZ AMG GLA45 S 2021; MERCEDES-BENZ AMG GLB35 2021-2023; MERCEDES-BENZ CLA 250 2021-2023; MERCEDES-BENZ GLA 250 2021-2023; MERCEDES-BENZ GLA 250 4MATIC 2021-2023; MERCEDES-BENZ GLB 250 2021-2023; MERCEDES-BENZ GLB 250 4MATIC 2021-2023
- Component, as stated by NHTSA
- POWER TRAIN
Text of the manufacturer communication
Complaint Customers may report one or more of the following: • Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after ignition cycle When performing a quick test, the following fault code is stored in Y3/14 ‑ Transmission control for 8‑speed dual‑clutch transmission (DKG): P056300 The on‑board power supply voltage is too high. Cause An overvoltage condition is detected exclusively within the transmission control unit, storing fault P056300 once the measured voltage exceeds 16V. Remedy This LI applies if the freeze frame data for P056300 show a supply voltage between 15.75 to 16.50 volts, and no other control units report overvoltage. (figure 1) Long Term Resolution: Software resolutions have been released. Check validity and ensure your Xentry is updated with latest Addons before continuing: 1. Perform software update for Y3/14 ‑ Transmission control for 8‑speed dualclutch transmission (DKG) available software listed in Parts 2. Clear fault memory and perform final test drive If the customer complaint matches this LI and the software currently installed on the vehicle is not listed, please submit a TIPS case to the Powertrain inbox with the following information: ‑ Initial Quick Test w/ Freeze Frame Data ‑ DKG Control Unit Log ‑ Latest EEPROM data ‑ Screenshot of software availability
- Manufacturer document number
- LI27.19-P-080823
- Date of the communication
- 2026-08-25
NHTSA reuses some ID numbers across record types. If its page lists more than one record, this one is the manufacturer communication dated Aug 31, 2026.