Can I bypass brake sensors entirely on a Bafang system?

Yes. Most Bafang controllers allow brake sensors to be bypassed by connecting the two brake sensor wires together (short circuit). This permanently tells the controller the brake is released. The motor will then respond normally to throttle and PAS without brake cutoff. Note this disables the motor cutoff safety feature when braking.

Bafang E-Bike Error 33: Brake Detection Circuit Fault Fix

What Error 33 Means

Error 33 on Bafang eBike systems signals that the brake detection circuit is showing a permanently activated state — the controller thinks the brakes are permanently engaged. Bafang systems use magnetic brake sensors (or motor inhibitor switches) in the brake levers. When a brake is pulled, the sensor sends a signal that cuts motor output. Error 33 means this cut-off signal is permanently active even when no brakes are applied.

The practical symptom is often not error 33 directly but rather motor output being completely absent — the bike starts without error but the motor never engages. Error 33 typically appears when the fault is persistent enough for the controller to log it.

Fix Procedure

Step 1: Disconnect Brake Sensors One at a Time

Locate the brake sensor connectors — typically small 2-pin connectors on the brake lever cables that plug into the main harness. Disconnect the front brake sensor connector. Power on and test if motor now responds. If yes, the front brake sensor is permanently activated. Reconnect the front and repeat with the rear.

Step 2: Inspect the Brake Lever Magnet

The Bafang magnetic brake sensor works by detecting a small magnet on the brake lever body moving away from the sensor when the lever is pulled. When the lever is released, the magnet should move back close to the sensor. If the magnet has shifted position, fallen off, or if the sensor has moved, the sensor reads "activated" permanently. Check that the magnet is in the correct position on the lever body.

Step 3: Test the Sensor

On a 2-wire Bafang brake sensor, use a multimeter on continuity mode: at rest (brake released) the sensor should show open circuit (no continuity). With the brake pulled, it should show closed circuit (continuity). A sensor that shows closed circuit regardless of brake lever position has failed.

Step 4: Replace the Sensor

Bafang brake sensors are inexpensive (EUR 5 to EUR 15) and plug-and-play replacement. If you prefer not to use brake sensors, they can be bypassed on most Bafang controllers by connecting the two sensor wires together — this tells the controller the brake is permanently released.

Bafang E-Bike Error Code 33: Brake Sensor Fault