How to troubleshoot brake sensor errors Follow

Follow this guide for how to resolve your brake sensor errors.

To perform this fix you will need a 2mm Allen Key and a 7mm Wrench.

Symptoms

• Both Throttle and PAS do not work 
• Error 37 on Stunner LT 
• Error 03 Bafang motors, Stunner, Stunner X, Juggernaut Classic, Juggernaut Classic HD, Juggernaut Ultra, Juggernaut Ultra FS
• This symbol is staying on screen after brakes are released 

Step 1: Determine which motor cutoff switch is causing issues

• Trace the wires coming from brake sensor 
• Disconnect both (Left/Right yellow connectors) brake cut-off switches, ride the bike for a couple minutes and see if the issue reoccurs. If the motor stops cutting out, then there might be an issue with either one of the switches (L or R).
• Connect the right brake cut-off switch. Leave the left brake cut-off switch disconnected, ride the bike for a couple minutes, see if the problem reoccurs. If the issue reoccurs then there is a problem with the Right switch.
• Connect the left brake cut-off switch. Disconnect the right brake cut-off switch, ride the bike for a couple minutes, see if the problem reoccurs. If the issue reoccurs then there is a problem with the left switch.

Step 2: Adjust Brake Lever adjustment screw

Mechanical Brakes

• Make sure levers are returning to original position freely 
  • 

    If Bad

    • A brake adjustment is a necessary DIY found here

If Good

• Tektro
  • Adjust Brake sensor alignment screw
  •  
    
    • Loosen the set screw by a few threads with the 2mm Allen Key
      
    • Loosen adjustment screw 1/2 turn with 7mm Wrench
      
    • Check if the motor cuts off while squeezing the brake
      • If the motor still cuts off with brake released loosen the adjustment screw by 1/4 turn and try again
      • If the motor does not cut off at all with the brake pressed tighten the adjustment screw 1/4 turn and try again
      • Repeat the process until the symbol no longer stays on the display with the brakes fully released and the symbol no longer shows up when riding without the brakes activated.
      • If needed try smaller adjustments to find the "sweet spot"
    • The adjustment screw changes sensitivity of the brake cutoff switch
      • Having this screw looser will trip the cutoff with more brake pressure

      • Having this screw tighter will trip the cutoff with less brake pressure

    • Once adjustment is complete tighten the Set Screw back to it's original position.
• Other
  • Remove lower cover 
  • Check for physical blockage and smooth movement of switch 
  • If neither fixes contact support for replacement

Hydraulic

• Tektro
  • Adjust Brake sensor alignment screw
  •  
    
    • Loosen set screw
      
    • Loosen adjustment screw 1/2 turn
      
    • Check if the motor cuts off while squeezing the brake
      • If the motor still cuts off with brake released loosen the adjustment screw by 1/4 turn and try again
      • If the motor does not cut off at all with the brake pressed tighten the adjustment screw 1/4 turn and try again
      • Repeat the process until the symbol no longer stays on the display with the brakes fully released and the symbol no longer shows up when riding without the brakes activated.
      • If needed try smaller adjustments to find the "sweet spot"
    • The adjustment screw changes sensitivity of the brake cutoff switch
      • Having this screw looser will trip the cutoff with more brake pressure

      • Having this screw tighter will trip the cutoff with less brake pressure

    • Once adjustment is complete tighten the Set Screw back to it's original position.