84 | Controller - Controller communication error

Troubleshoot battery communication errors.

Written by Alex Kovell

Last published at: September 9th, 2025

Table of Contents

1 Prepare for E-Bike Inspection 2 When the controller is in BTL mode, connect to HST to perform rescue process 3 Check the connector between Controller and HMI 4 Examine the cable, connectors and pins 5 Reboot the e-bike Rule out the possibility of Torque sensor issue Rule out the possibility of Motor issue 6 Replace the Controller 7 Replace the HMI 8 Reach out to the Service Team if you need additional support!

Description

System communication with the controller is interrupted due to a potential connection issue between components. This disruption can lead to erratic behavior or malfunctions in the bike's performance, as the controller relies on accurate data transmission to regulate functions such as power assistance levels and motor control. Promptly addressing and resolving this connection issue is imperative to ensure seamless communication and optimal operation of the bike system.

⚠️ Triggers of Error Code

The following are possible causes of error code 84:

  • Any component, except for the battery, may cause error code 84 due to an abnormality, leading to communication interruptions between parts.

1 Prepare for E-Bike Inspection

Before proceeding with the inspection, ensure the e-bike is stationary. Do not sit on the bike, pedal, or apply any force to the pedals. Long press the power button to turn off the e-bike.

mceclip0.png
 
 

2 When the controller is in BTL mode, connect to HST to perform rescue process

When the controller is in BTL mode, please connect the bike to HST and perform the rescue process.If the error code persists, please proceed to the next step.

(Note:The Bluetooth function still operates normally when the controller is in BTL mode.)

 

CC-02_Controller-Bootloader.gif

LCD Compact

1_CE-03-Error.gif

LED Multi

4_CE-05-Error.gif

LED Chip 2
CE-EL19A

CE-TR19A_Error.gif

CE-TR19A

 

 
 

3 Check the connector between Controller and HMI

Find the connection cable between [Controller] and [HMI], and check if the cable connector is plugged in properly. If the connection is loose, plug the connector back in tight carefully. When plugging the connectors, ensure the arrow symbols on the two connectors must be aligned.

Tips: If there's an extension cable connecting the [Controller] and [HMI] on this e-bike, replace it with a new spare. Then, turn on the e-bike to check if the error code persists. If the issue is not resolved, proceed to the next step.

 
 

4 Examine the cable, connectors and pins

Check the cable for damage. Then, unplug the cable connector and examine the connector pins for bends or breakage. If any issues are found, replace the damaged component or extension cable. If both the cable and connector are in good condition, proceed to the next step.

 
 

5 Reboot the e-bike

Repeat the above steps to check all component connections with the Controller. After inspection, reboot the e-bike to check if the error code persists. If the issue is not resolved, proceed to the next step.
system_reboot_icon_180895.png

 
 

Rule out the possibility of Torque sensor issue

Disconnect the connector between [Torque sensor] and [Controller]. Reboot the e-bike to check for the error code. If the error code 84 doesn't appear, replace [Torque sensor]. If the error code persists, proceed to the next step.


How to replace Torque sensor?

 
 

Rule out the possibility of Motor issue

Disconnect the connector between [Motor] and [Controller]. Reboot the e-bike to check for the error code. If the error code 84 doesn't appear, replace [Motor]. If the error code persists, proceed to the next step.


How to replace Motor?

 
 

6 Replace the Controller

Replace the [Controller] with a new spare, then reboot the e-bike to check if the error code still exists. If this doesn't fix the issue, proceed to the next step.

 
 

7 Replace the HMI

Replace the [HMI] with a new spare, then reboot the e-bike to check if the error code still exists. If this doesn't fix the issue, proceed to the next step.

 
 

8 Reach out to the Service Team if you need additional support!

Contact Customer Care or the Hyena Service Center for further technical assistance.

 
 

 

Source

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