Vehicle Error Codes Reference

When a vehicle reports an error, it appears in the Status & telemetry section of the vehicle detail page. This guide explains every error code, what it means, and what to do about it.

Severity levels:

Critical — Vehicle should not be ridden. Fix before deploying.
Error — Significant issue that needs attention. May affect performance or safety.
Warning — Minor issue. Vehicle may still operate but should be inspected soon.

OKAI Scooter Errors

These errors are reported by OKAI scooter ECU (Electronic Control Unit) and IoT modules, including ES300, ES400, ES600, and EB100 models.

Controls and Safety

Head lamp fault

Severity: Warning

The headlight circuit has failed. The scooter can still be ridden during daylight, but should not be deployed for evening or night use.

What to do:

Check the headlight bulb/LED connection
Inspect the wiring harness to the headlight
Replace the headlight assembly if the connection is solid but the light doesn't work

Meter firmware lost

Severity: Error

The dashboard display has lost its firmware. The scooter may still function but the rider won't see speed, battery level, or other telemetry on the display.

What to do:

Power cycle the scooter (turn off, wait 10 seconds, turn on)
If the display remains blank after power cycling, the display module may need replacement
Contact your vehicle supplier for a firmware reflash if available

Turning handle fault

Severity: Critical

The throttle sensor or wiring has a fault. The throttle may behave unpredictably — it could fail to respond or could send incorrect speed signals.

What to do:

Do not deploy this scooter until resolved
Inspect the throttle cable and connector for damage or disconnection
Check for water ingress in the throttle housing
Replace the throttle assembly if the wiring is intact

The throttle is physically stuck in a non-zero position and hasn't sprung back to the resting/neutral position. The scooter's controller refuses to unlock as a safety measure — if it unlocked with throttle engaged, the scooter would immediately accelerate.

What to do:

Do not deploy this scooter until resolved
Physically push the throttle grip all the way back to the resting position
Check for debris, a bent grip, or a cable pinch preventing the throttle from returning to zero
If the throttle moves freely but the error persists, the throttle sensor (hall sensor) inside the grip is faulty — replace the grip assembly
Power cycle the scooter after fixing, then retry the unlock

Left brake crank fault

Severity: Critical

The left brake lever sensor has failed. The scooter cannot reliably detect when the rider is braking.

What to do:

Do not deploy this scooter until resolved
Check the brake lever sensor connector
Inspect the brake lever for physical damage
Replace the brake lever assembly if the sensor is faulty

Right brake crank fault

Severity: Critical

The right brake lever sensor has failed. Same as left brake — the scooter cannot reliably detect braking.

What to do:

Do not deploy this scooter until resolved
Check the brake lever sensor connector
Inspect the brake lever for physical damage
Replace the brake lever assembly if the sensor is faulty

Left brake crank not returned

Severity: Critical

The left brake lever is stuck in the engaged/pressed position. The scooter may apply regenerative braking continuously or refuse to accelerate.

What to do:

Do not deploy this scooter until resolved
Check if the brake lever physically springs back when released
Look for debris or cable binding preventing the lever from returning
If the lever moves freely, the brake sensor is faulty — replace the brake lever assembly

Right brake crank not returned

Severity: Critical

The right brake lever is stuck in the engaged/pressed position. Same issue as the left brake — continuous braking or refusal to accelerate.

What to do:

Do not deploy this scooter until resolved
Check if the brake lever physically springs back when released
Look for debris or cable binding preventing the lever from returning
If the lever moves freely, the brake sensor is faulty — replace the brake lever assembly

Communication Errors

ECU heartbeat error

Severity: Error

The IoT module has lost communication with the main controller board (ECU). Commands may fail and telemetry may be stale.

What to do:

Power cycle the scooter
Check the internal wiring between the IoT module and the ECU
If the error persists after power cycling, the ECU or IoT module may need replacement

BMS heartbeat error

Severity: Error

The IoT module has lost communication with the Battery Management System (BMS). Battery level readings may be inaccurate and charging protection may not function.

What to do:

Power cycle the scooter
Check the battery connector and internal wiring
Ensure the battery is properly seated in its housing
If the error persists, the BMS board inside the battery may be faulty

Meter heartbeat error

Severity: Warning

The IoT module has lost communication with the dashboard display. The scooter still functions but the display may be blank or show stale data.

What to do:

Power cycle the scooter
Check the display cable connection
Usually resolves on its own after a power cycle

Abnormal communication with Hub-Lock

Severity: Warning

The IoT module is having trouble communicating with the hub lock. Lock and unlock commands may be delayed or fail.

What to do:

Power cycle the scooter
Check the wiring from the IoT module to the hub lock motor
If lock/unlock commands consistently fail, the hub lock motor or its controller may need replacement

Temperature and Charging

Over legal charging temperature

Severity: Error

The battery temperature is too high for safe charging. The BMS has disabled charging to prevent damage or fire risk.

What to do:

Stop charging immediately
Move the scooter to a cool, shaded area
Wait for the battery to cool down before attempting to charge again
Do not charge in direct sunlight or in enclosed hot spaces

Discharging over heating

Severity: Critical

The battery is overheating during use. This is a fire risk if the scooter continues to operate.

What to do:

Stop riding immediately
Power off the scooter and move it away from people and flammable materials
Allow the battery to cool completely before inspecting
Check for cell damage or swelling — if the battery is swollen, do not use it

Charging under temperature

Severity: Warning

The battery is too cold for safe charging. Charging lithium batteries below freezing can cause permanent damage.

What to do:

Move the scooter to a warmer environment (above 40°F / 5°C)
Wait for the battery to warm up before charging
Do not attempt to force-charge in cold conditions

Discharging under temperature

Severity: Warning

The battery is too cold for optimal performance. The scooter will have reduced range and power but can still be used with caution.

What to do:

Expect reduced range in cold weather
If possible, store scooters indoors overnight during cold months
Performance will return to normal as the battery warms during use

MOS over heating

Severity: Critical

The power electronics (MOSFET transistors) inside the battery are overheating. This can lead to component failure or fire.

What to do:

Stop riding immediately
Power off and allow the scooter to cool completely
Inspect for signs of electrical damage or burning smell
If the error recurs, the battery pack needs professional inspection or replacement

Other over heating

Severity: Error

A temperature sensor outside the main battery cells is reading too high. This could be the controller, motor, or another component.

What to do:

Stop riding and allow the scooter to cool
Check if the motor or controller housing is abnormally hot
Inspect for blocked ventilation or debris around heat-generating components

Pre-discharge error

Severity: Critical

The battery's pre-discharge circuit has failed. The battery cannot safely deliver power to the motor.

What to do:

Do not deploy this scooter
The battery pack likely needs replacement
Do not attempt to bypass this protection — it exists to prevent short circuits

Pre-charge error

Severity: Error

The battery's pre-charge circuit has failed. The battery may not charge properly or may charge unsafely.

What to do:

Do not charge this battery until inspected
The battery pack may need replacement
Check the charger and charging port for damage

Voltage and Current Protection

Under voltage first layer protection

Severity: Warning

Battery voltage is getting low. This is the first warning — the scooter can still operate but should be charged soon.

What to do:

Charge the scooter as soon as practical
If this appears on a scooter that was just charged, the battery may have a weak cell

Under voltage second layer protection

Severity: Critical

Battery voltage is critically low. The BMS is shutting down power output to prevent permanent battery damage from deep discharge.

What to do:

Charge immediately — deep discharge damages lithium cells permanently
If the scooter won't charge after reaching this level, the battery may already be damaged
If this happens repeatedly despite charging, the battery needs replacement

Over voltage first layer protection

Severity: Warning

Battery voltage is higher than normal. This can happen briefly during regenerative braking on a full battery.

What to do:

Usually transient — monitor to see if it clears
If persistent, stop charging and check the charger output voltage
Do not use a third-party charger that may output the wrong voltage

Over voltage second layer protection

Severity: Error

Battery voltage is dangerously high. The BMS is actively protecting against overcharge.

What to do:

Stop charging immediately
Disconnect the charger
Check the charger — it may be outputting the wrong voltage
Only use the manufacturer-specified charger

Over current first layer protection

Severity: Warning

The motor is drawing more current than usual. This can happen on steep hills or with heavy riders.

What to do:

Reduce speed on hills
Usually transient — monitor the error
If it appears frequently on flat ground, the motor may have increased resistance (bearing issue or winding fault)

Over current second layer protection

Severity: Error

Significant current overload detected. The controller is reducing power to protect the battery and wiring.

What to do:

Reduce speed and avoid steep inclines
Check for a dragging brake or seized bearing that would increase motor load
If persistent, inspect the motor and controller connections

Over current third layer protection

Severity: Critical

Severe current overload. The scooter is at risk of wiring damage or fire.

What to do:

Stop riding immediately
Check for short circuits, damaged wiring, or a seized motor
The scooter needs professional inspection before redeployment

Over current fourth layer protection

Severity: Critical

Maximum current protection triggered. The BMS has cut power to prevent immediate damage.

What to do:

Do not ride
This indicates a serious electrical fault — likely a short circuit or major component failure
Professional inspection and likely component replacement required

Battery and BMS

Cell temperature sensor damage

Severity: Error

The temperature sensor inside the battery pack is broken. The BMS cannot accurately monitor battery temperature, which reduces its ability to protect against overheating.

What to do:

The battery can still be used with caution in moderate temperatures
Schedule battery replacement — running without temperature monitoring is risky long-term
Avoid charging in extreme heat or cold

Large charging discharging temperature difference

Severity: Warning

The temperature sensors inside the battery are reading very different values, suggesting uneven heating. This can indicate a failing cell or poor thermal management.

What to do:

Monitor the battery closely
If the imbalance grows worse over time, schedule battery inspection
Usually not immediately dangerous but indicates aging battery cells

Charging fuse broken

Severity: Critical

The internal charging fuse has blown. The battery cannot be charged.

What to do:

The battery needs professional repair or replacement
The fuse blew to protect against a fault — simply replacing the fuse without diagnosing the cause risks fire
Do not attempt to bypass the fuse

Discharging fuse broken

Severity: Critical

The internal discharge fuse has blown. The battery cannot deliver power to the motor.

What to do:

The battery needs professional repair or replacement
Same as charging fuse — diagnose the root cause before replacing
The scooter is inoperable until fixed

Cell imbalance

Severity: Warning

The individual cells in the battery pack have drifted apart in voltage. This reduces effective capacity and can worsen over time.

What to do:

Perform a full charge cycle (charge to 100%, then use until low, then charge again)
Some BMS boards auto-balance during full charge — leave the charger connected for a few extra hours
If imbalance persists after several full cycles, the battery is aging and may need replacement

Cell drop

Severity: Critical

One or more battery cells have failed entirely. The battery is dangerous to use — a dead cell can cause the remaining cells to overcharge.

What to do:

Remove this battery from service immediately
Do not charge or use this battery
Replace the battery pack

Charging over current

Severity: Error

The charging current is higher than the BMS allows. This usually means the wrong charger is being used.

What to do:

Disconnect the charger immediately
Verify you're using the correct charger (check voltage and amperage ratings)
Do not use fast chargers or third-party chargers that aren't rated for the battery

System Components

Failed to communicate with protection chip

Severity: Error

The BMS cannot communicate with the hardware protection IC. This chip provides a last line of defense against overcurrent and overvoltage.

What to do:

Power cycle the scooter
If the error persists, the battery needs professional inspection
Operating without the protection chip is risky — schedule repair promptly

Metering device damage

Severity: Warning

The coulomb counter or fuel gauge chip inside the battery is damaged. Battery percentage readings may be inaccurate.

What to do:

The scooter can still operate but battery level shown to riders will be unreliable
Schedule battery replacement when practical
Riders may experience unexpected shutdowns if the displayed level is wrong

Flash chip damage

Severity: Error

The flash memory chip in the BMS is damaged. The BMS may lose calibration data and configuration.

What to do:

The battery may still function but BMS behavior may be degraded
Schedule battery replacement
If the battery behaves erratically (unexpected shutdowns, wrong readings), remove from service

Charge MOS damage

Severity: Critical

The charging MOSFET transistor is damaged. The battery cannot safely control charging current.

What to do:

Do not charge this battery — charging without the MOSFET controlling current risks overcharge and fire
Replace the battery pack

Discharge MOS damage

Severity: Critical

The discharge MOSFET transistor is damaged. The battery cannot safely control power output.

What to do:

Do not ride — the battery cannot limit current delivery, risking wiring damage or fire
Replace the battery pack

MCU ROM damage

Severity: Critical

The BMS microcontroller's read-only memory is corrupted. The BMS firmware is compromised and battery protection logic may not function correctly.

What to do:

Remove from service immediately
The battery pack needs replacement — ROM corruption cannot be field-repaired

MCU RAM damage

Severity: Critical

The BMS microcontroller's RAM is faulty. Real-time battery protection calculations may be wrong.

What to do:

Remove from service immediately
The battery pack needs replacement

Controller and Motor

Controller under voltage

Severity: Error

The main motor controller isn't receiving enough voltage. This can be caused by a weak battery, corroded connectors, or damaged wiring.

What to do:

Check the battery level — charge if low
Inspect the main power connector between battery and controller for corrosion or looseness
If the battery is charged and connectors are clean, the controller may be faulty

Controller firmware lost

Severity: Critical

The motor controller has lost its firmware. The scooter cannot operate.

What to do:

Do not deploy
The controller needs a firmware reflash or replacement
Contact your vehicle supplier for controller firmware

ECU upper MOS damage

Severity: Critical

One of the high-side power transistors in the motor controller has failed.

What to do:

Do not ride — a damaged MOSFET can cause short circuits or uncontrolled motor behavior
Replace the motor controller

ECU lower MOS damage

Severity: Critical

One of the low-side power transistors in the motor controller has failed.

What to do:

Do not ride
Replace the motor controller

Motor hall fault

Severity: Critical

The motor's hall effect sensors have failed. These sensors tell the controller the rotor position — without them, the motor cannot be driven correctly and may jerk, stall, or spin uncontrollably.

What to do:

Do not ride
Check the motor hall sensor cable connection at the controller
If the cable is connected and undamaged, the motor's internal hall sensors are faulty — replace the motor or motor assembly

Motor phase line fault

Severity: Critical

One or more of the three motor phase wires are damaged, disconnected, or shorted.

What to do:

Do not ride — phase faults can cause the motor to lock up or the controller to overheat
Inspect the three thick motor wires for damage, cuts, or loose connectors
If the wires are intact, the motor windings may be damaged — replace the motor

Motor temperature protection

Severity: Error

The motor is overheating. The controller is reducing power to protect the motor windings.

What to do:

Stop riding and allow the motor to cool
Check for a dragging brake pad rubbing on the disc
Check for debris wrapped around the wheel or axle increasing friction
In hot weather, motors may overheat under heavy load (hills, heavy rider) — this is normal but the scooter should rest and cool

Motor stalling

Severity: Critical

The motor has stalled — it's receiving power but not spinning. This causes extreme current draw and rapid overheating.

What to do:

Stop immediately — a stalled motor can burn out the controller and wiring in seconds
Check for mechanical obstructions (debris in wheel, seized bearing)
If the wheel spins freely by hand, the motor windings may be shorted — replace the motor

ECU abnormal shutdown

Severity: Error

The ECU (motor controller) shut down unexpectedly — it powered off without going through a normal shutdown sequence. This is typically caused by a sudden loss of power, a voltage spike, a controller fault, or the battery being disconnected while the scooter was running.

What to do:

Power cycle the scooter (turn off, wait 10 seconds, turn on)
Check the main power connector between the battery and controller for looseness or corrosion
If the battery was recently swapped, make sure it's seated and connected properly
If the error clears after power cycling, monitor for recurrence — a single instance after a rough ride or power interruption is usually benign
If it recurs frequently, inspect the controller for heat damage or faulty capacitors and consider replacement

ECU MOS over temperature

Severity: Critical

The power transistors in the motor controller are overheating. This usually follows sustained high-current operation.

What to do:

Stop riding and allow the controller to cool
Check for adequate ventilation around the controller housing
If recurring, the controller may need replacement or the motor load is too high (check for mechanical drag)

ECU firmware lost

Severity: Critical

The motor controller has lost its firmware. The scooter cannot operate without firmware — it won't respond to commands or rider input.

What to do:

Do not deploy
The controller requires a firmware reflash or replacement
Contact your vehicle supplier for the correct firmware version for this controller model

Device rebooted

Severity: Warning

The IoT module rebooted unexpectedly. This can happen due to a watchdog timeout (the firmware detected a hang and self-recovered), a power interruption, or a firmware fault. A single reboot is usually harmless — the device reconnects automatically and normal operation resumes.

What to do:

If the device is online and reporting normally, no action needed
If reboots are frequent (multiple per day), check the power supply to the IoT module and inspect the wiring for intermittent disconnections
If the device doesn't come back online after rebooting, power cycle the scooter

Vehicle overturned

Severity: Error

The IoT module's accelerometer detected that the scooter has fallen over or been knocked down. The error shows a state of detected (tilt sensor triggered), confirmed (sustained tilt beyond recovery threshold), or unknown (state couldn't be determined).

What to do:

Physically check the scooter — right it if it's on its side
Inspect for visible damage (mirrors, fenders, display, cables)
The error will clear automatically once the scooter is upright and a new telemetry report is received
If the scooter is upright but still shows this error, power cycle it to force a fresh status report

Service request

Severity: Warning

The vehicle's IoT module received a remote service or maintenance request signal. This is typically triggered by a technician command or an automated maintenance workflow.

What to do:

Check the dashboard task list for any associated maintenance task
If unexpected, verify no automated maintenance jobs targeted this vehicle in error
The error will clear once the service request is acknowledged or completed

Torque pedal not in position

Severity: Warning

The pedal-assist sensor (on e-bike models) is not reading the correct resting position.

What to do:

Check the pedal sensor alignment
Inspect the sensor magnet on the crank arm
Usually a minor adjustment fixes this — refer to the model-specific repair guide

OKAI Lock and Unlock Failures

These errors appear when a lock or unlock command fails at the vehicle level.

Error or timeout occurred while locking

Severity: Error

The lock command was sent but the hub lock motor didn't confirm it completed in time.

What to do:

Retry the lock command from the dashboard
If the lock motor is jammed, there may be debris in the lock mechanism
Power cycle the scooter and retry

Error or timeout occurred while unlocking

Severity: Error

The unlock command was sent but didn't complete successfully.

What to do:

Retry the unlock command
Check the vehicle's IoT connection status — the device may be offline
Power cycle and retry

ECU type unmatched

Severity: Error

The IoT module doesn't recognize the connected ECU (controller). This can happen after a controller replacement if the new controller isn't the expected model.

What to do:

Verify the replacement controller is the correct model for this scooter
The IoT module may need reconfiguration to accept the new ECU type

ECU timeout

Severity: Error

The ECU (controller) didn't respond to the unlock sequence in time.

What to do:

Power cycle the scooter
Check internal wiring between IoT module and ECU
If persistent, the ECU may be faulty

Main battery type unmatched

Severity: Error

The IoT module doesn't recognize the connected battery. This can happen after a battery swap if the replacement battery has a different BMS protocol.

What to do:

Verify the replacement battery is the correct model
The IoT module may need reconfiguration

Main battery timeout

Severity: Error

The battery didn't respond during the unlock sequence.

What to do:

Check the battery connection — it may be loose or disconnected
Ensure the battery has charge
Power cycle and retry

ECU and main battery timeout

Severity: Error

Both the controller and battery failed to respond during unlock. This usually indicates a power issue.

What to do:

Check if the scooter has power at all (any lights, display)
The main power connector may be disconnected
If the scooter is completely dead, charge the battery or check the main fuse

Main battery not powered

Severity: Error

The battery is not delivering power. The scooter cannot unlock because there's no power to run the motor controller.

What to do:

Check battery charge level
Verify the battery is properly connected
Try charging — the battery may be in deep discharge protection mode
If the battery won't accept a charge, it may need replacement

Battery lock unlock failed

Severity: Error

The command to unlock or lock the battery compartment failed. This is distinct from the wheel lock — it refers to the removable battery's locking mechanism.

What to do:

Retry the battery unlock command from the dashboard
Physically inspect the battery compartment — debris or a bent latch may be blocking the mechanism
Power cycle the scooter and retry
If the mechanism is jammed, the battery lock actuator may need replacement