Bafang Error 30: Communication Fault (Display to Controller TX/RX Lost) — 3-Step Fix & Part Fitment
Cause: Display powers on from battery voltage, but serial UART/CAN communication lines (Green/Yellow wires) between display and motor controller are interrupted. Ride Status: STOP — No PAS or Throttle Response. Signal Pattern: Error 30 / 30H on Display. Most riders resolve ERR 30 in 10–20 min using the 3-step diagnostic checklist below (starting with the free mechanical/connector reset before ordering a €0 – €24 replacement sensor).
Interactive 3-Step Workshop Repair Checklist (Check as You Test)
Unplug the green 5-pin Higo connector near the handlebars and the main 8-pin 1T4 splitter cable near the motor. Check for a bent gold pin—forcing a Higo plug without aligning the molded arrows bends the TX/RX pin and causes instant Error 30.
A wet or shorted brake cut-off sensor or thumb throttle on the 1T4 harness pulls down the shared 5V controller regulator, starving the communication chip. Unplug BOTH brake sensors and the throttle, leaving only the display connected, then power on.
If all pins are straight and unplugging peripherals doesn't clear Error 30, the internal signal wire inside the 1T4 EB-Bus cable has snapped at the headtube bend. Swap the 1T4 harness.
Model Variant Pinout & Part Compatibility Matrix
| Model / Generation | OEM Part / Ref | Connector / Harness Type | Workshop Installation Note |
|---|---|---|---|
| Bafang BBS01 / BBS02 / BBSHD Mid-Drive | BF-1T4-EBBUS | 8-Pin Waterproof Main Harness to 4-Way Splitter | Most frequent cause is bent pin on the green 5-pin display plug. |
| Rad Power / Engwe / Aventon / Hub Motors (KT & Bafang) | KT-1T4-WP | Julet Waterproof 1T4 Harness | Unplug headlight and brake sensors first to rule out 5V rail short. |