# Service bulletin LI54.10\-P\-080199

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.

- Type: Service bulletin
- NHTSA id: 11027656
- Published by NHTSA: 2026\-01\-14
- Manufacturer's number: LI54.10\-P\-080199
- Manufacturer's date: 2026\-01\-14
- NHTSA component: ELECTRICAL SYSTEM

## NHTSA's summary

Complaint For the potentially affected vehicles, excessively high aging of the battery was calculated at cold battery temperatures \(\<10°C\) and the MIL activated accordingly, even though there is no corresponding high level of aging physically. In this regard, the fault code P0A7F00 "The age limit of the hybrid/high\-voltage battery module has been reached" is displayed in the N127 PTCU control unit and/or A66 battery module control unit \(48 V battery\). Cause Faulty computation of the age limit of the 48 V battery. Remedy Step 1: Software update of A66 battery module \(48 V battery\) Step 2: Perform reset routine: 2.1 Read out actual value 056 in A66 control unit \(age limit SOH\-R\) a. If SOH\-R \<= 125%: Delete fault memory in PTCU control unit \(N127\) and 48 V battery \(A66\). Process ended. b. If SOH\-R \> 125%: Drive for 60 min to add SOH\-R value. 2.2 Read out actual value 056 in A66 control unit \(age limit SOH\-R\) a. If SOH\-R \<= 125%: Delete fault memory in PTCU control unit \(N127\) and 48 V battery \(A66\). Process ended. b. If SOH\-R \> 125%: Park vehicle \> 12 hours in the workshop at a warm ambient temperature \> 15°C, then drive for 60 min. 2.3 Read out actual value 056 in A66 control unit \(age limit SOH\-R\) a. If SOH\-R \<= 125%: Delete fault memory in PTCU control unit \(N127\) and 48 V battery \(A66\). Process ended. b. If SOH\-R \> 125%: Create TIPS case

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11027656-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11027656-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system

## Trouble codes named

P0A7F

## Vehicles listed

- 2023 to 2024 MERCEDES\-BENZ AMG C43
- 2023 to 2026 MERCEDES\-BENZ AMG C43 4MATIC
- 2024 MERCEDES\-BENZ AMG C63 S E
- 2024 to 2025 MERCEDES\-BENZ AMG C63 S E 4MATIC\+
- 2026 MERCEDES\-BENZ AMG C63 S E PERFORMANCE 4MATIC\+
- 2023 MERCEDES\-BENZ AMG E53E
- 2024 MERCEDES\-BENZ AMG GLC43
- 2024 to 2026 MERCEDES\-BENZ AMG GLC43 4MATIC
- 2024 to 2025 MERCEDES\-BENZ AMG GLC43 4MATIC COUPE
- 2025 MERCEDES\-BENZ AMG GLC63 S E
- 2025 to 2026 MERCEDES\-BENZ AMG GLC63 S E 4MATIC\+
- 2025 to 2026 MERCEDES\-BENZ AMG GLC63 S E 4MATIC\+ COUPE
- 2023 to 2025 MERCEDES\-BENZ AMG S 63 E 4MATIC\+
- 2022 to 2026 MERCEDES\-BENZ C 300
- 2022 to 2026 MERCEDES\-BENZ C 300 4MATIC
- 2025 to 2026 MERCEDES\-BENZ E 350
- 2024 to 2026 MERCEDES\-BENZ E 350 4MATIC
- 2024 MERCEDES\-BENZ E 450
- 2024 to 2026 MERCEDES\-BENZ E 450 4MATIC
- 2024 to 2026 MERCEDES\-BENZ E 450 4MATIC ALL\-TERRAIN
- 2025 MERCEDES\-BENZ E53 E 4MATIC\+
- 2026 MERCEDES\-BENZ E53 E 4MATIC\+ ALL\-TERRAIN
- 2023 to 2026 MERCEDES\-BENZ GLC 300
- 2023 to 2026 MERCEDES\-BENZ GLC 300 4MATIC
- 2024 to 2026 MERCEDES\-BENZ GLC 300 4MATIC COUPE
- 2024 MERCEDES\-BENZ GLC 300 COUPE
- 2025 to 2026 MERCEDES\-BENZ GLC 350 E 4MATIC
- 2026 MERCEDES\-BENZ GLC43 4MATIC COUPE
- 2021 MERCEDES\-BENZ S 500
- 2023 MERCEDES\-BENZ S 500
- 2022 to 2025 MERCEDES\-BENZ S 500 4MATIC
- 2021 MERCEDES\-BENZ S 580
- 2023 MERCEDES\-BENZ S 580
- 2022 to 2025 MERCEDES\-BENZ S 580 4MATIC
- 2023 MERCEDES\-BENZ S 580 E
- 2023 to 2025 MERCEDES\-BENZ S 580 E 4MATIC
- 2021 MERCEDES\-MAYBACH S 580
- 2022 to 2025 MERCEDES\-MAYBACH S 580 4MATIC
- 2023 to 2024 MERCEDES\-MAYBACH S 680
- 2022 to 2023 MERCEDES\-MAYBACH S 680 4MATIC
- 2025 MERCEDES\-MAYBACH S 680 4MATIC

JSON: [/v1/bulletins/11027656](/v1/bulletins/11027656)

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