This article explains how to troubleshoot the W03 Controller Overheat Protection warning on an Aventon eBike.

Use this article if your bike:

• Shows a W03 warning code
• Loses motor assistance during riding
• Stops assisting after heavy riding or climbing
• Feels unusually hot after use

If you are unsure of your Aventon model, please confirm your model before continuing.

Stop troubleshooting immediately if anything looks unsafe, overheated, damaged, or smells burnt.

Before You Start

Please prepare the following:

• Order number
• Aventon model
• Photo or video of the W03 warning code
• Photo of the display
• Photo of the controller area, if relevant
• When the issue first appeared
• Whether the bike powers on
• Whether the display turns on
• Whether the motor engages
• Whether the issue happened during climbing, heavy riding load, transport, storage, water exposure, crash, impact, modification, or third-party repair
• Photos of visible damage

Safety Warnings

• Do not continue riding if the bike is overheating, smoking, or has a burning smell.
• Do not continue riding if the bike behaves abnormally or loses power unexpectedly.
• Do not open sealed electrical components.
• Do not work on wiring while the bike is powered on or charging.
• Stop and contact support if you are unsure.

What This Warning Means

The W03 Controller Overheat Protection warning means the controller has overheated due to prolonged use.

The system may automatically shut off power output to help prevent damage.

This may happen during heavy riding conditions such as climbing steep hills with maximum pedal assist.

Possible Causes

Possible causes include:

• Controller overheating from prolonged use
• Extended climbing with maximum pedal assist
• Heavy riding load
• Damaged controller
• Damaged motor

Troubleshooting Steps

Step 1 – Allow the Bike to Cool Down

Turn the bike off before continuing.

Allow the bike to cool down for 1 hour.

After cooling:

• Restart the bike
• Check whether the W03 warning returns

If yes – The W03 warning still appears

Continue to Step 2.

If no – The warning clears

The issue was likely caused by temporary controller overheating during heavy riding conditions.

To help prevent overheating:

• Lower the pedal assist level during climbs
• Take short breaks during extended climbing
• Reduce prolonged heavy motor load

Monitor the bike during future riding.

If the issue clears

Continue normal use and monitor the bike.

If the issue remains

Continue to Step 2.

Step 2 – Check Whether the Warning Persists

After the bike has cooled down and restarted, check whether the W03 warning returns during riding.

If yes – The W03 warning still appears

The issue may involve the controller system.

Please contact our support team with the photos/videos listed below so we can review the next step.

If no – The warning no longer appears

The issue was likely caused by temporary overheating during prolonged riding load.

Continue monitoring the bike during use.

Step 3 – Check Riding Conditions

Check whether the issue happened:

• During steep climbing
• With maximum pedal assist
• During prolonged heavy riding
• During hot weather conditions

If yes

The controller may have entered protection mode due to excessive heat.

Reduce pedal assist during long climbs and allow cooling breaks during heavy riding.

If no

The issue may involve the controller system.

Please contact support for further assessment.

If the issue remains

Please contact support.

Step 4 – Inspect for Visible Controller Damage

Inspect the accessible controller area for:

• Visible damage
• Burning smell
• Signs of overheating
• Water exposure
• Impact damage
• Damaged cables or connectors

If yes – Visible damage is found

Stop using the bike immediately.

Do not continue riding or charging the bike.

Please contact our support team with photos/videos of the controller area.

If no – No visible damage is found

Restart the bike and check whether the W03 warning returns.

If the issue remains

The controller or motor system may require further inspection.

Please contact support.

Step 5 – Check Whether Motor Problems Continue

Check whether:

• The motor does not engage
• Motor assistance cuts out repeatedly
• The bike loses power during riding
• The W03 warning returns repeatedly

If yes

The issue may involve:

• The controller system
• Motor communication
• The motor system

Please contact our support team with:

• Video of the issue
• Video of the display during riding
• Photos of accessible connectors and wiring

If the issue remains

Please contact support.

When To Contact Support

Please contact support if:

• The W03 warning remains after completing these checks
• The motor does not engage
• The bike overheats repeatedly
• There is visible controller damage
• The bike shuts down repeatedly during normal riding
• The bike has been exposed to water, crash, impact, transport damage, modification, or third-party repair
• You are unsure how to safely complete a step

If the issue remains after these steps, please contact our support team and include the photos/videos listed below.

What To Send Support

Please send:

• Order number
• Aventon model
• Photo/video of the W03 warning code
• Photo of the display
• Photo/video of the controller area
• Photos of visible damage
• Confirmation of whether the bike powers on
• Confirmation of whether the display turns on
• Confirmation of whether the motor engages
• Confirmation of whether the issue happened during climbing, heavy riding, or hot weather
• Confirmation of whether the bike overheats repeatedly
• Confirmation of whether the issue happened after water exposure, crash, impact, modification, or third-party repair
• Confirmation of the troubleshooting steps already completed

Important Safety Notes

• Do not continue riding if the W03 warning remains.
• Do not ride the bike if there is visible damage, overheating, smoke, burning smell, or abnormal bike behaviour.
• Do not open the controller, motor, battery, or sealed electrical components.
• Do not force connectors.
• Do not work on wiring while the bike is powered on or connected to the charger.
• Contact support if you are unsure.