Location
Kaunas, Lithuania
Smart Media Connect: CAN Filter Installation Guide
The Smart Media Connect navigation unit (also known as “Smart Media – System Connect”) becomes locked when removed from its original SMART 453 vehicle, making it unusable for bench testing or retrofitting into another car. On every startup, the unit checks security codes with the vehicle’s immobilizer system. If the codes don’t match, the device displays a lock screen.
Locked device displays a message in several languages:
“DEVICE IS LOCKED !”, “APPAREIL BLOQUÉ !”, “GERÄT IST GESPERRT !”, “NAPRAWA ZAKLEJENA !”
To bypass this restriction, a CAN filter (immobilizer emulator) can be installed. This device allows the unit to function in another vehicle or on a test bench by overriding the security check.
Smart Media Connect Applications
The Smart Media Connect navigation unit is used in the following Smart 453 series vehicles:
- Smart Fortwo (C453) 2015-2024
- Smart Forfour (W453) 2015-2024
- Smart EQ Fortwo (C453, A453) 2015-2024
- Smart EQ ForFour (C453, A453) 2015-2024
Supported Part Numbers
Below are some of the supported part numbers for Smart Media Connect units. Please note that the list is not exhaustive:
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Mercedes-Benz Part Numbers:
A4539014402,A4539016502,A4539017302, … -
Renault Part Numbers:
259150408R,259157424R,259157473R, … -
Bosch Part Numbers:
7503700000,7503700005,503700006, …
Head Unit Connectors
The Smart Media Connect head unit features ISO connectors on the rear panel, along with several additional antenna and USB connectors. Below is the rear view of the unit and a basic pinout diagram showing the minimum required connections to power up the device on a bench or in a retrofit installation.
CAN Bus Filter Configuration
⚠️ Important: The CAN filter must be configured for Smart Media Connect units by soldering jumper J2 on the PCB.
When testing the unit on a bench or retrofitting it into a vehicle other than the SMART 453, the navigation unit requires a wake-up signal on the CAN bus. Supplying Ignition (ACC) and VCC (12V+) through the external power connector is not sufficient to power on the device.
To provide the necessary wake-up signal, jumpers J1 and J2 on the CAN filter must be connected. This enables the CAN filter to broadcast the wake-up command to the navigation unit.
CAN Bus Filter Installation
The CAN bus filter (immobilizer emulator) can be installed in one of two ways: externally on the wiring or internally inside the head unit.
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🔧 External Installation
Installing the CAN filter externally — on the harness or test bench wiring — is ideal for bench testing or non-professional use. This method is easier, reversible, and does not require opening the navigation unit. -
🛠 Internal Installation
For a cleaner and more integrated solution, the CAN filter can be installed inside the Smart Media Connect unit. This method allows the unit to function seamlessly in any compatible vehicle without external wiring. By performing an internal installation, there is no need for external wiring modifications, offering a clean, OEM-like appearance and permanent security override functionality.⚠️ Note: Professional Installation Recommended
Internal installation requires advanced electronics knowledge and soldering skills. It is recommended for professionals only due to the complexity and risk of damaging internal components.
External CAN Bus Filter Installation
To override the immobilizer system for testing on a bench or to install the unit in a different vehicle, the CAN filter can be connected externally as follows:
🔌 Power Supply:
- +12V → Connect to ignition voltage (ACC)
- GND → Connect to ground
🔗 CAN Bus Connection:
- CAN2 → Connect to the unit’s CAN lines
- Required for bench testing
- CAN1 → Connect only during vehicle installation
💡 Bench Testing Setup:
For bench operation:
- Only CAN2 ↔ CAN connection is required.
- CAN1 can be left disconnected.
🚗 Vehicle Installation Scenario:
For in-vehicle use:
- Cut the CAN wires in the vehicle’s harness.
- Connect the CAN1 side of the filter to the vehicle CAN.
- Connect the CAN2 side of the filter to the head unit.
- This places the CAN filter in series between the car and the navigation unit, allowing it to filter or emulate signals as needed.
Internal CAN Bus Filter Installation
⚠️ Warning: Professional Handling Required
Working with internal components of the navigation unit exposes sensitive electronics to electrostatic discharge (ESD) and the risk of permanent damage.
Always follow ESD safety precautions and use proper tools when soldering or handling the PCB.
Internal installation should only be performed by experienced technicians.
Working with internal components of the navigation unit exposes sensitive electronics to electrostatic discharge (ESD) and the risk of permanent damage.
Always follow ESD safety precautions and use proper tools when soldering or handling the PCB.
Internal installation should only be performed by experienced technicians.
To perform an internal CAN filter installation, follow these steps:
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Disassemble the Navigation Unit
Carefully open the Smart Media Connect unit to gain access to the mainboard components.
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Attach the CAN Filter PCB
Secure the CAN filter board to the mainboard using hot glue, double-sided tape, or another proper method to avoid movement and short circuit during operation. -
Locate Connection Points
Identify the necessary connection points on the mainboard as shown in the reference images below.
-
Modify the CAN Bus Line
Remove the two resistors on the CAN bus line to allow proper integration of the emulator.
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Connect the Filter
Solder the +5V, GND, and CAN lines from the filter to the mainboard, following the diagram below.
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Reassemble and Test
Reassemble the unit and apply power to verify proper startup and functionality.
⚠️ Final Important Note: Initial Code Learning Process
When the CAN filter is connected for the first time to a Smart Media Connect unit, it must automatically learn the unit’s security codes. This process takes approximately 30 seconds.During this process:
When the CAN filter is connected for the first time to a Smart Media Connect unit, it must automatically learn the unit’s security codes. This process takes approximately 30 seconds.During this process:
- The navigation unit displays “DEVICE LOCKED”.
- The CAN filter’s LED blinks to indicate learning is active.
- When finished, the LED turns off and the lock screen disappears.
✅ This process occurs only once per unit. On future startups, the system will boot immediately.
🔁 If the CAN filter is installed in a different unit, the learning cycle will automatically run again.
⚠️ Do not disconnect or power off the system during the learning phase.
▶️ Watch: CAN Filter Initial Learning Process
This short video demonstrates the first-time learning process of the CAN filter when connected to a Smart Media System Connect unit.
You’ll see the LED blinking during code learning and the “DEVICE LOCKED” screen disappearing once the process is complete.
Hello Zelemar , looking for a solution for the A453 900 1003 (Smart 453 2015) and the related pin out (unit differs from the shown instruction set) in the way the connections are done.
Do you do such an item / regards Ian G
Hi, it should be a R-Link radio and pinout is different from Bosch Smart Media-System connect. I haven’t tested my emulator on this unit.
The wiring diagram for R-Link can be found here: https://evilution.co.uk/mod/453-multimedia-radio-pin-out.htm