JB4 ECU CANbus Harness (OBDII Alternative) for BMW G Chassis

Simplify your G Chassis BMW and GR Supra JB4 installation with our new Direct CANbus Harness. This plug-and-play harness connects the JB4 directly to the vehicle’s CANbus at the ECU, eliminating the need to route a CAN/OBDII cable through the firewall and into the passenger compartment.

The result is a cleaner, faster, and easier JB4 installation with no need to run wires inside the passenger compartment to access the OBDII port under the dash.

Also allows passive CANbus mode where the JB4 uses read only channels for its basic tuning, allowing full use of the OBDII port for logging via MHD or any other scan tool during full throttle runs! 

NOTE: Requires compatible JB4 or JB4PRO firmware and settings to enable. For JB4PRO B58/S58 systems turn on option 11 to enable, and turn on option 12 to run the JB4PRO in passive mode only. In passive mode certain channels such as AFR and timing corrections are not available, so this mode would normally only be used while the OBDII port is otherwise occupied. Not compatible with 2025+ Gen3 B48/B58 platforms.

Features & Benefits

• Direct CANbus connection at the ECU
• Eliminates routing wiring into the passenger compartment
• Cleaner, more professional installation
• Significantly reduces installation time and hassle
• Plug-and-play design for G Series B58 S58 BMW and B58 Supra
• Higher CANbus sample rate being directly on PTCAN

Vehicle fitment