SpecAuto New Version Mercedes CAN Filter/CAN Blocker Fbs3/4 Emulator PCB

The SpecAuto New Version Mercedes CAN Filter / CAN Blocker FBS3 / FBS4 Emulator PCB is a small electronic module used on Mercedes-Benz vehicles that operate on FBS3 and FBS4 systems (common in models like W204, W212, W222, W205, W213, etc.).

🔧 What it is

It is a CAN-bus signal modification device (PCB module) designed to:

• Filter or block specific CAN messages
• Interfere with communication between modules (EZS, ECU, cluster, gearbox, etc.)
• Prevent or alter synchronization between control units
• Modify diagnostic or system communication behavior on the CAN line

In most listings it is described as a “CAN Filter / CAN Blocker PCB” or “FBS3/FBS4 emulator”.

Simple summary

It’s basically a small PCB module that sits on the CAN network of Mercedes cars and alters or blocks communication between electronic control units, mainly for advanced diagnostic or modification purposes.