A2059052809 Auxiliary Battery Voltage Converter

A2059052809 Voltage converter also known as Auxiliary Battery.

A205 905 28 09 replacement voltage converter is factory fitted to many different cars such as: C W205 S205 C205 GLC C253 E W213 S213 C238 S W222.

Voltage converter is direct replacement to aftermarket or mercede benz brand part.

It is used in Eco Stop Start function and it recharged by regenerative braking system.

Mercedes voltage converter location is at the passenger front side footwell place.

To access and replace part you will need to remove some protection parts, move carpet a little bit backwards and under the second layer of protection part you will find and access auxiliary battery voltage converter.

Capacitor is located at the same place for all cars.

What is the failure symptoms of Mercedes-Benz voltage converter?

The most common issue and symptom of failing voltage converter is Auxiliary Battery Malfunction warning message.

Once you see this fault message there is no need to visit dealer shop and do secondary diagnostic and spend extra money as dealer suggests.

No coding is required after replacing voltage module.

The most common Mercedes-Benz warning messages

• Auxiliary Battery Malfunction
• Backup-batteri Fejl
• Batterie de reserve defaut
• Bateria auxiliar falha
• Batería auxiliar Avería
• Backup Batterie Störung
• Backup-batterie Fejl
• Backup-batteri störning
• Zalozni akumulator Porucha
• Backup accu Storing
• Backup batteria anomalia
• Usterka akumulatora dodatkowego
• Yedekleme akusu Ariza

The most common diagnostic trouble codes DTCs

• B21DC01 - The buffer battery of the electronic ignition lock has a malfunction. There is a general electrical fault
• B21DC01 The buffer battery of the electronic ignition switch (EIS/EZS) is faulty. A general electrical fault exists

Mercedes-Benz part numbers

• A205 905 28 09
• A2059052809

Compatible Mercedes-Benz cars

• C Cass W205 Saloon Sedan
• C Class S205 Estate Wagon
• C Class A205 Cabriolet Convertible
• C Class C205 Coupe
• C Class 2014 2015 2016 2017 2018
• C180d C200d C220 BlueTec C250d diesel
• C300 C400 C450 4MATIC C43 C63 AMG petrol gasoline
• C350e Plug In Hybrid
• CLC W257 2017 2018 2019
• E ClasS W213 Sedan Saloon
• E Class S213 Estate Wagon
• E Class C238 Coupe
• E Class A238 Convertible
• E Class 2016 2017 2018 2019
• E Class E200 E250 E300 E350e Hybrid E400 E450
• E200d E220d E300d E350d E400d 4MATIC AMG Line
• E43 E63 AMG
• GLC X253 C253 W253 Hatchback Coupe 2015 2016 2017 2018 2019
• GLC GLC300 GLC350e GLC220d GLC 220d GLC250d GLC350d 4MATIC GLC43 GLC63 AMG
• S Class W222 Sedan 2013 2014 2015 2016 2017 2018
• S Class C217 Coupe 2013 2014 2015 2016 2017 2018
• S Class S300 BlueTec S320 S350 S400 Hybrid S500 S550 S65 S63 AMG
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Please note: this list is not full, sensor may fit other car models as well.