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Service bulletin LI54.10-P-079534

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11021802
Published by NHTSA2025-08-12
Manufacturer's numberLI54.10-P-079534
Manufacturer's date2025-08-08
NHTSA componentELECTRICAL SYSTEM

NHTSA's summary

Complaint: Red 12 V battery warning message in IC DTC stored in EZS or currently: B161609 No DTC in DC/DC converter DC/DC converter is not providing any output voltage or output current Cause: Due to a reduction in resistance at the HV voltage divider, the DC/DC converter measures an incorrect HV voltage. Regulation of the 12 V output voltage is therefore unstable or turns off. Remedy: Check of the DC/DC converter via XENTRY Diagnosis Actuate BUCK mode for approx. 40 s Normally, the output current will jump up to a high value (e.g. 100 A) and then slowly drop to the current specified value (e.g. 50 A) and then only change slowly and in small increments (video in attachment). In the event of this error cause, the DC/DC converter may react in two possible ways: 1) Despite displayed BUCK mode, the DC/DC converter does not provide any output voltage or output current (video in attachment). 2) The output voltage and output current may experience significant fluctuations/jumps (several 1-10 A) (video in attachment). Perform in XENTRY -> DC/DC converter N83/1 -> Special procedures -> "Evaluation of the HV resistance reduction of the DC/DC converter control unit". The special procedure compares the serial number of the installed DC/DC converter with the list of potentially affected parts. Depending on the result: If the serial number can be found in the list of potentially affected component parts, then replace the DC/DC converter. If the serial number cannot be found in the list of potentially affected parts but the problem described applies, then please open a TIPS case and forward to HQ.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system

Trouble codes named

B1616

Vehicles listed
MERCEDES-BENZ AMG EQS2022 to 2024
MERCEDES-BENZ AMG EQS 532022 to 2023
MERCEDES-BENZ AMG EQS 53 4MATIC2023 to 2024
MERCEDES-BENZ EQS 4502022
MERCEDES-BENZ EQS 450 4MATIC2023 to 2024
MERCEDES-BENZ EQS 450+2022 to 2024
MERCEDES-BENZ EQS 5802022 to 2024
MERCEDES-BENZ EQS 580 4MATIC2022 to 2023
MERCEDES-BENZ EQS SUV 450 4MATIC2023 to 2025
MERCEDES-BENZ EQS SUV 450+2023 to 2025
MERCEDES-BENZ EQS SUV 580 4MATIC2023 to 2025
MERCEDES-BENZ redundant EQS 4502023 to 2024
MERCEDES-MAYBACH EQS SUV 680 4MATIC2024 to 2025

Listing a model year does not mean every vehicle of it is concerned: the document says which.