Error Code 04 Troubleshooting: Alpha IIUpdated 20 days ago

Uh oh! It's Error Code 04! 

What's Error Code 04?

The error code denotes a fault with the brake cutoff sensor(s) installed on the underside of the Shimano MT200 brake levers on your Alpha II. The goal of the brake cutoff switch is to cut power to the motor when the brakes are applied. 

Brake Cutoff Components

The system is comprised of two components on either brake lever:

1) An MT200 lever, the magnet, and the sensor 

The magnet, specific to the right and left sides, clips onto the hinge where the lever connects to the master cylinder. 

The sensor is attached to the clamp body using the clamp bolt, which affixes the lever to the handlebar.

2) Magnet and sensor installed correctly

For the system to work as intended, the magnet must be within range of the sensor but not too close. If that magnet is either out of range or too close, the sensor will throw the fault, and you'll see Err 04 on your handlebar display.

Possible Causes

• The magnet is either too close or too far away from the sensor.
• The sensor is corrupted. 
• The bike has fallen over or been knocked, and the wires within the sensor have become dislodged from the circuit board.

Solutions

1. Identify which sensor is causing the fault:
   1. Unplug the rear (right) side sensor while the bike is powered on. Hold either plug firmly and gently rock it back and forth while pulling them apart. Do not twist these plugs! 
   2. If the error remains on the display, plug in the right-side sensor and unplug the front (left) side sensor. 
   3. Plug in both sensors once you've identified which side is causing the fault. 
2. Ensure the magnet is fully seated and clipped to the brake lever.
   1. Refer to image 2 for a correctly installed magnet and sensor
3. If the magnet is installed correctly, use a 2mm hex wrench to adjust the brake lever reach outwards by turning clockwise:
   1. You should only need to adjust the reach by a quarter to half-turn

If the troubleshooting steps outlined in this guide do not resolve the error code, please email [email protected] for further assistance!