Mercedes B-Class Radio Code — Unlock It Online

Your Mercedes B-Class stereo is displaying CODE or asking for a number after a battery change or a few weeks without power — this is completely normal. Every B-Class fitted with a Becker-made head unit (sold under the Audio 10, Audio 20, or Audio 5 branding) stores a unique four- or five-digit unlock code that is tied to the serial number on the radio itself. This guide walks you through exactly how to find that serial and how to get back on the road with your music.

Why Your B-Class Radio Is Locked

Mercedes-Benz installs a PIN-lock on its OEM radios as a theft deterrent. Whenever the unit loses power — whether the battery went flat, you disconnected it, or the car sat in a garage for an extended period — the radio reboots into a protected state and demands a code before it will operate. The unit is not broken; it simply will not play until you supply the correct PIN.

For B-Class owners, the relevant audio head units are manufactured by Becker (a Harman subsidiary) and appear in the dashboard as Audio 5, Audio 10 CD, Audio 20, or the more advanced COMAND NTG systems. Depending on trim level and year, you may have a simple push-button unit or a touchscreen system with navigation.

Finding the Serial Number

The serial number is the key that links your specific radio to its unlock code. On Mercedes B-Class models, the serial carries a BE prefix (sometimes shown as BE/—). Here are the two reliable methods to retrieve it:

Button-combination method (no removal needed)

1. Switch the ignition to position II (accessories on), but do not start the engine.
2. With the radio displaying CODE, press and hold preset buttons 1 and 6 simultaneously for approximately two seconds.
3. The display should briefly show a serial string beginning with BE followed by several digits.
4. Write this sequence down exactly — it is case-sensitive.

If the button combination does not work on your unit (some NTG touchscreen variants behave differently), proceed to the label method.

Reading the label on the unit itself

1. Use a set of DIN radio extraction keys (or two flat-headed tools wrapped in tape) to release the head unit from the dashboard.
2. Look for a white or silver sticker on the top or side of the unit.
3. Note the serial number beginning with BE.
4. Re-seat the unit in the dashboard without fully reconnecting it if you just want to note the serial.

Getting Your Unlock Code Online

Once you have the serial number, the fastest route is to order your code through an online decoding service. Visit our supported brands page to confirm Mercedes B-Class compatibility, then submit the serial. Most codes are delivered within minutes to your email address. You will not need to visit a dealer or wait for a postal response card.

1. Go to our order page and select Mercedes as the brand.
2. Enter the full serial number including the BE prefix.
3. Pay securely and receive your code by email, usually within minutes.
4. Follow the entry instructions below to unlock the radio.

Entering the Code

Entry differs slightly between the push-button Audio units and the COMAND/touchscreen systems:

Push-button Audio 10 / Audio 20 units

1. Switch on the ignition; the radio will show CODE.
2. Use preset buttons 1–4 (or 1–5 on five-digit codes) to enter each digit of your code. Each press of a button increments that digit upward — button 1 controls the first digit, button 2 the second, and so on.
3. When all digits are set correctly, press the OK or seek button (on some units, press and hold button 5 or the FM button) to confirm.
4. The radio should return to normal operation immediately.

COMAND NTG touchscreen systems

1. The touchscreen will prompt for a code on-screen.
2. Use the on-screen keypad or the COMAND controller to enter each digit.
3. Confirm with the central OK button.

Differences by Generation

The B-Class has undergone three generations, each bringing a different infotainment architecture:

Generation	Years	Typical Radio	Serial Prefix	Entry Method
B-Klasse I (W245)	2005–2011	Audio 5 / Audio 10 CD	BE	Preset buttons 1–4
B-Klasse II (W246)	2011–2018	Audio 20 / NTG4.5	BE	Buttons or COMAND controller
B-Klasse III (W247)	2018–2025	MBUX / Audio 20 NTG6	BE / VIN-linked	Touchscreen or dealer only

Note: W247 models with MBUX may use a VIN-linked system that cannot be unlocked with a standalone code — in that case a Mercedes dealer is required. Check your head unit model before ordering.

Troubleshooting Common Error Messages

If you encounter a message other than CODE, here is what each state means:

• CODE — Normal locked state; enter your code now.
• SAFE — The unit detected multiple wrong attempts and has entered a safety lockout. Switch the ignition on (without starting the engine) and leave it on for 30–60 minutes; the unit will reset and show CODE again.
• WAIT — Similar to SAFE; the radio is counting down an enforced delay. Do not switch off the ignition — allow the countdown to complete.
• LOCKED — The maximum wrong-attempt threshold (typically ten attempts) has been reached. The radio requires a dealer reset or a longer wait period (up to one hour with the ignition on).
• ERR — The code you entered does not match. Double-check the serial number and that you ordered the correct code for your unit type.
• 1000 — Not applicable to Mercedes; this display is more common on Volkswagen/Audi group units.

If you have exhausted your attempts, do not guess further codes. Contact our support team with your serial number and we will verify the correct code before you try again.

Frequently Asked Questions

How many wrong attempts am I allowed before the radio locks permanently?

Most Mercedes OEM radios manufactured by Becker allow up to ten incorrect entries before entering an extended lockout. After that, you typically need to leave the ignition on (engine off) for one full hour before the radio resets and allows further attempts. It does not lock permanently unless the unit is a VIN-bound COMAND system.

Can I get the code from a Mercedes dealership?

Yes, most dealers can retrieve the code using your VIN, though this often involves an administration fee and may require proof of ownership. An online service is faster and generally less expensive for Becker-based Audio units.

My B-Class radio says SAFE every time I switch it on — is it broken?

No. SAFE appears when the unit is in lockout mode following multiple wrong attempts. Switch the ignition on (accessories position, engine off) and wait up to one hour without switching off. Once the lockout expires, CODE will reappear and you can try again.

Does my W247 B-Class need a code at all?

The W247 (2018 onward) may use the MBUX infotainment platform, which in many configurations is bound to the vehicle's VIN rather than relying on a standalone PIN. If your unit does not display CODE after a power loss, it is likely VIN-linked and unlocks automatically when connected to the correct vehicle — no code needed, but also not transferable.

Where can I find more information about other Mercedes models?

We cover the full Mercedes range including the A-Class, C-Class, E-Class, GLC, and CLA. Visit our Mercedes brand page to see all supported models and order a code instantly.