Unlocking/repairing the 48-volt hybrid battery – Mercedes-Benz

Unlocking and repairing 48-volt hybrid batteries used in Mercedes-Benz vehicles.

Most common symptoms:

❌ No start
❌ Starter does not turn
❌ The message “48-volt battery - see user manual / malfunction”

The most common causes of the problem:

• Locking after an accident (accident data);
• Deep discharge of the 48-volt battery;
• Intentional discharge or disconnection of the battery during sea transportation (USA).

In such cases, the car does not start, despite a working 12-volt system.

Service area:

• Unlocking the 48-volt battery after an accident;
• Unlocking after a deep discharge;
• Restoring the normal operation of the mild hybrid system;
• Removing software and logical locks.

Replacing the battery is not required, the car is not coded required.

Common errors stored in control units:

• B183349 – Internal electrical fault of the 48-volt battery;
• B183319 – Low voltage mild hybrid system error;
• B183371 – 48-volt battery malfunction;
• B183384 – Battery signal is out of range.

Supported 48V battery numbers:

• A0009820216
• A0009820416
• A0009820316
• A0009823217
• A0009823316
• A0009823317
• A0009823413
• A0009823417
• A0009823513
• A0009823516
• A0009824212
• A0009824220
• A0009824312
• A0009824420
• A0009824520
• A0009825213
• A0009825313
• A0009826222
• A0009826714
• A0009826814
• A0009827113
• A0009827116
• A0009827216

Affected Mercedes models:

• C-Class W205
• E-Class W213
• E Coupe / Cabrio W238
• GLC W253
• CLS W257
• GLE/GLS W167
• S-Class W222
• AMG GT C209

and other versions with 48-volt mild hybrid system.

Why is it worth it?

• Experience with Mercedes-Benz electronics.
• No need to buy a new, very expensive 48-volt battery.
• No need to reprogram another used/new battery.
• Solving a problem typical of American-made cars.