Fatbike error codes explained – malfunctions & solutions

Are you getting an error code on your fat bike display and is your electric fat bike no longer working properly? On this Hero Fatbikes page, you'll find a complete and clear overview of the most common fat bike error codes , including an explanation of the error and possible solutions.

Below you can look up your fat bike error code for each display type, such as QMWHEEL (H6C display) , OUXI (M5 display) , and the C80 fat bike (C80 display) . Click on the error code to immediately see what it means , what the possible cause is , and what you can do .

Are you having trouble or does the problem keep recurring? Hero Fatbikes is ready to help you with advice, repairs, and parts.

Here you will find all meanings and solutions of possible error codes

Error codes V20 Pro QMWHEEL (H6C Display)

Code E01 – Engine fault / engine cable problem

What does this error code mean?

Error code E01 indicates a problem with the motor or motor cable. The display is not receiving a correct signal from the motor.

Possible causes:


  • Loose or damaged motor cable

  • Internal engine error

  • Short circuit in the motor

What can you check/do:


  • Check that the motor cable is properly secured

  • Inspect the cable and connectors for damage

  • If the error persists, the engine may be defective

Need a motor or motor cable? Everything is in stock at Hero Fatbikes.

Code E02 – Brake active / brake fault

What does this error code mean?

Error code E02 indicates that the system thinks the brake is being pressed, which switches off motor support.

Possible causes:


  • Brake lever sensor defect

  • Brake switch sticks

What can you check/do:


  • Check that both brake levers return fully

  • Inspect brake sensors and wiring

  • Test if the error disappears by disconnecting one brake

Brake sensors and brake levers are in stock at Hero Fatbikes.

Code E04 – Communication error (display ↔ controller)

Code E04 – Communication error

What does this error code mean?

Error code E04 indicates a communication problem between the display and the controller.

Possible causes:


  • Bad connection display ↔ controller

  • Cable break

  • Plugs not connected properly

What can you check/do:


  • Check all communication cables

  • Disconnect and reconnect plugs

  • Inspect connectors for dirt or damage

👉 Displays, controllers and cables are immediately available from Hero Fatbikes.

Code E08 – Low battery voltage

What does this error code mean?

Error code E08 indicates that the battery voltage is too low.

Possible causes:


  • Battery almost empty

  • Loose or poor wiring

  • Voltage drops under load

What can you check/do:


  • Fully charge the battery

  • Check battery connections and wiring

  • Check whether the voltage remains stable during use

Batteries and chargers for QMWHEEL fat bikes are available directly from Hero Fatbikes.

Code E10 – Communication or reception error

Code E10 – Communication reception/error

What does this error code mean?

Error code E10 indicates a communication problem between the display, controller or battery.

Possible causes:


  • Poor connection of plugs

  • Damage to controller or cabling

  • Mismatch between display and controller

What can you check/do:


  • Check all connectors and cables

  • Disconnect and reconnect

  • If necessary, test or replace the controller

👉 Displays and controllers are in stock at Hero Fatbikes.

Code E20 – Throttle error / Throttle setting

What does this error code mean?

Error code E20 indicates that the throttle is incorrectly set or remains active.

Possible causes:


  • Incorrect throttle setting

  • Throttle input remains active

What can you check/do:


  • Check throttle signal and wiring

  • Reset the settings if necessary

  • Test whether the error disappears after correction

Throttles and displays are immediately available from Hero Fatbikes.

Code E40 – Engine short circuit / serious engine fault

What does this error code mean?

Error code E40 indicates a serious engine fault or short circuit.

Possible causes:


  • Internal winding defect

  • Short circuit in the motor

  • Engine not responding to controller

What can you check/do:


  • Inspect engine internally

  • Measure for short circuit

  • Replace engine if proven defective

New QMWHEEL engines and parts are available directly from stock at Hero Fatbikes.

Here you will find all meanings and solutions of possible error codes

Error codes OUXI V8 (M5 Display)

Code E00 – Normal operation

What does this error code mean?

Error code E00 means the fat bike is functioning normally . There is no malfunction.

Possible causes:


  • No error detected

What can you check/do:


  • No action required

Do you have any questions about how your OUXI M5 display works? Hero Fatbikes is happy to help.

Code E01 – Engine failure

What does this error code mean?

Error code E01 indicates a problem with the motor or motor cable . The controller is not receiving a correct signal from the motor.

Possible causes:


  • Motor cable loose or damaged

  • Internal engine failure

  • Short circuit in the motor

What can you check/do:


  • Check that the motor connector is properly secured

  • Inspect the motor cable for damage

  • If the error persists, the engine may be defective

Need a motor or motor cable? These are available directly from stock at Hero Fatbikes .

Code E02 – Brake active / brake fault

What does this error code mean?

Error code E02 means that the system thinks the brake is pressed , which switches off motor support.

Possible causes:


  • Brake lever sensor defect

  • Brake switch sticks

  • Loose or damaged brake cable

  • Brake lever does not return properly

What can you check/do:


  • Check that both brake levers return fully

  • Inspect brake sensors and wiring

  • Test if the error disappears by disconnecting one brake

Brake sensors and brake levers are in stock at Hero Fatbikes .

Code E03 – PAS sensor error

What does this error code mean?

Error code E03 indicates a fault in the PAS (pedal assistance) sensor .

Possible causes:


  • PAS sensor defective

  • Cable break

  • Magnet ring incorrectly mounted

What can you check/do:


  • Check the PAS sensor connection

  • Inspect cable and magnet ring

  • Check that the sensor is aligned correctly

Wiring is available directly from Hero Fatbikes .

Code E04 – Communication error

What does this error code mean?

Error code E04 indicates a communication problem between the display and the controller .

Possible causes:


  • Bad plug connection

  • Cable break

  • Corrosion in connectors

What can you check/do:


  • Check all display and controller cables

  • Disconnect and reconnect plugs

  • Inspect connectors for dirt or corrosion

👉 Displays, controllers and cable sets are in stock at Hero Fatbikes .

Code E05 – Cruise / real-time cruise error

What does this error code mean?

Error code E05 relates to a malfunction in the cruise control function .

Possible causes:


  • Cruise setting not working properly

  • Software or controller problem

What can you check/do:


  • Check the display settings

  • Reset the OUXI M5 display

  • If the error persists, the controller may be defective

👉 Need a controller replaced or checked? Hero Fatbikes has everything in stock.

Code E06 – Undervoltage / low battery voltage

What does this error code mean?

Error code E06 indicates that the battery voltage is too low .

Possible causes:


  • Battery almost empty

  • Bad battery connector

  • Worn battery cells

  • Voltage drops under load

What can you check/do:


  • Fully charge the battery

  • Check battery connections

  • Test whether the voltage remains stable during use

👉 Batteries and chargers for OUXI fat bikes are immediately available from Hero Fatbikes .

Code E07 – Engine fault / hall sensor error

What does this error code mean?

Error code E07 usually indicates a problem with the hall sensors in the engine .

Possible causes:


  • Faulty hall sensors

  • Loose cable between motor and controller

  • Internal motor coil damaged

What can you check/do:


  • Check engine wiring

  • Inspect sensor connections

  • In case of persistent failure, engine replacement is often necessary

👉 OUXI engines and parts are in stock at Hero Fatbikes .

Code E08 – Low battery voltage / throttle fault

What does this error code mean?

Error code E08 may indicate low battery voltage or a malfunction in the throttle .

Possible causes:


  • Battery (almost) empty

  • Throttle malfunction

  • Bad throttle wiring

What can you check/do:


  • Fully charge the battery

  • Check throttle cable and connectors

  • If the battery no longer charges, it may be defective

Need a throttle, battery, or wiring? We have everything in stock at Hero Fatbikes .

Code E09 – Controller error

Error code E09 means that the controller detects an internal fault .

Possible causes:


  • Overload

  • Overheating

  • Moisture or internal damage

What can you check/do:


  • Disconnect the controller and reconnect it

  • Check for moisture or heat

  • If the error persists, replacement is necessary

New OUXI controllers are immediately available at Hero Fatbikes .

Code E10 – Communication error

What does this error code mean?

Error code E10 indicates a communication problem between display, controller and battery .

Possible causes:


  • Damaged cables

  • Bad plug connection

What can you check/do:


  • Check all communication cables

  • Reset the system

  • The display or controller may be defective.

We have displays and controllers in stock for quick resolution .

Code E11 – Variant communication error

What does this error code mean?

Error code E11 is a variant of E10 and also indicates a communication failure.

Possible causes:


  • Same causes as with E10

What can you check/do:


  • Perform the same checks as for Code E10

👉 Hero Fatbikes helps you quickly with diagnosis and parts .

Code E12 – BMS communication error

What does this error code mean?

Error code E12 means that there is no good communication with the BMS (Battery Management System) .

Possible causes:


  • BMS defect

  • Bad battery connector

What can you check/do:


  • Check the battery connections

  • Reset the BMS if possible

  • If the error persists, battery replacement is necessary

Batteries with BMS are in stock at Hero Fatbikes .

Code E13 – Headlight error

What does this error code mean?

Error code E13 indicates a fault in the headlight or the light connection .

Possible causes:


  • Lamp defect

  • Cable break

What can you check/do:


  • Test the headlight separately

  • Check light cables and connection

Headlights and cable sets are available directly from Hero Fatbikes .

Code E20 – Throttle error (setting)

What does this error code mean?

Error code E20 indicates an incorrect throttle setting .

Possible causes:


  • Throttle input remains active

  • Display setting incorrect

What can you check/do:


  • Reset settings:

    press and hold + and – at the same time → go to P06 → set value to 000

Not working? Throttles and displays are in stock at Hero Fatbikes .

Code E40 – Engine failure / short circuit

What does this error code mean?

Error code E40 indicates a serious engine fault or short circuit .

Possible causes:


  • Internal motor coil defective

  • Short circuit in the motor

  • Controller detects motor fault

What can you check/do:


  • Test the motor with another controller (if possible)

  • If a short circuit is confirmed, engine replacement is necessary

New OUXI engines are available directly from stock at Hero Fatbikes .

Here you will find all meanings and solutions of possible error codes

Error codes OUXI (C80 Display)

Code E02 – Brake active / brake fault / brake signal detection

What does this error code mean?

Error code E02 indicates that the system thinks the brake is being pressed, which switches off motor support.

Possible causes:


  • Brake lever sensor defect

  • Loose brake cable

  • Switch remains pressed

  • Brake lever mechanically fixed

What can you check/do:


  • Check brake levers, brake cables and brake switch

  • Check that the brake lever returns completely to the neutral position

Brake sensors, brake levers and cabling are immediately available from Hero Fatbikes.

Code E05 – Overvoltage

What does this error code mean?

Error code E05 indicates that the battery or system is receiving too much voltage.

Possible causes:


  • Battery voltage too high

  • Charging problem

  • Defective component drawing too much tension

What can you check/do:


  • Measure the battery voltage

  • Check if the charger is compatible

  • Inspect controller and wiring for possible damage

👉 Chargers, controllers and cabling are available directly from Hero Fatbikes.

Code E06 – Undervoltage / low battery voltage

What does this error code mean?

Error code E06 indicates that the battery voltage is too low.

Possible causes:


  • Battery low

  • Loose connector

  • Bad battery cells or defective charging circuit

What can you check/do:


  • Fully charge the battery

  • Check all connectors and wiring

  • Test whether the voltage remains stable under load

👉 Batteries and chargers for C80 are immediately in stock at Hero Fatbikes.

Code E07 – Hall sensor engine fault / engine fault

What does this error code mean?

Error code E07 indicates a problem with the hall sensors or internal engine components.

Possible causes:


  • Hall sensors defective

  • Loose wire between motor and controller

  • Short circuit or open circuit in internal coils

What can you check/do:


  • Check cables to the engine

  • Disconnect the engine to inspect sensor connections

  • If error persists, replace engine

👉 Motors and hall sensors are immediately available from Hero Fatbikes.

Code E08 – Throttle fault

What does this error code mean?

Error code E08 indicates that there is a problem with the throttle lever.

Possible causes:


  • Throttle lever defect

  • Loose thread

  • Throttle lever remains on "gas"

  • Wrong resistance

What can you check/do:


  • Check throttle cable and connectors

  • Measure throttle resistance and signal

  • Clean or replace the throttle lever if necessary

Throttle levers are immediately in stock at Hero Fatbikes.

Code E09 – Controller error

What does this error code mean?

Error code E09 indicates an internal error in the controller.

Possible causes:


  • Controller internal defect

  • Overload or heat problem

  • Damaged internal components

What can you check/do:


  • Ensure proper cooling of the controller

  • Check that the controller is dry and intact

  • Disconnect and reconnect

  • Replace the controller if necessary

    New C80 controllers are immediately available from Hero Fatbikes.

Code E10 – Communication error

What does this error code mean?

Error code E10 indicates a communication problem between the display, controller or battery.

Possible causes:


  • Bad connections

  • Damaged cables

  • Signal loss

What can you check/do:


  • Check all communication cables and connectors

  • Check if the display is receiving signals

  • Reset the system

  • Test whether display or controller needs to be replaced

Displays, controllers and cables are in stock at Hero Fatbikes.

Code E16 – Communication variants

What does this error code mean?

Error code E16 is similar to E10 and concerns communication problems.

Possible causes:


  • See E10

What can you check/do:


  • Perform the same checks as for Code E10

Hero Fatbikes supplies all necessary parts directly from stock.

Code E21 – Speed ​​sensor / Crank sensor error

What does this error code mean?

Error code E21 indicates a problem with the speed sensor.

Possible causes:


  • Magnets not properly aligned

  • Sensor loose or damaged

  • Cable break

What can you check/do:


  • Check magnets on the spoke

  • Inspect sensor distance and mounting

  • Check for corrosion or moisture in connectors

Pedal sensors and accessories are available directly from Hero Fatbikes.

All parts immediately available | Hero Fatbikes

Whether you have a V20 Pro, V8, or C80 fat bike, you can order all your parts directly from Hero Fatbikes. From motors, controllers, and displays to brake sensors, throttles, batteries, and cables – everything is in stock and ready to ship.

Do you have questions about an error code or need advice on replacing parts? Our team is ready to help!

Call us: 06 30 19 82 89

WhatsApp us: 06 30 19 82 89

Choose fast service, expert advice and parts that work – all at Hero Fatbikes .

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