Aventon Mid-Drive Bikes – E45 Speed Sensor Error TroubleshootingUpdated 2 days ago
This article explains how to troubleshoot the E45 “Speed Sensor Error” on Aventon mid-drive bikes.
Use this article if your bike:
- Shows error code E45
- Displays “Speed Sensor Error”
- Has inaccurate speed readings
- Experiences intermittent pedal assist behavior
- Does not properly detect wheel speed
If you are unsure about any step or notice anything unsafe, stop troubleshooting and contact support.
Before You Start
Please prepare the following:
- order number
- Aventon model
- photo or video of the issue
- photo of the E45 error code
- when the issue first appeared
- whether the bike powers on
- whether the battery charges
- whether the display turns on
- whether the motor engages
- whether the issue happened after charging, riding, transport, storage, wheel removal, rotor replacement, water exposure, crash, impact, modification, or third-party repair
- photos of any visible damage
Safety Warnings
- Do not continue riding if the bike has visible damage, overheating, smoke, burning smell, water exposure, or a persistent error code.
- 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 Error Means
E45 indicates a speed sensor fault involving the speed sensor system.
The issue may be caused by:
- a faulty speed sensor
- a missing or damaged speed sensor magnet
- damaged speed sensor wiring
- communication issues between the speed sensor and mid-drive unit
Possible Causes
- damaged speed sensor
- damaged speed sensor magnet
- damaged speed sensor harness
- damaged cable between the speed sensor and mid-drive unit
- worn cable
- broken connector
- internal open circuit
Important Installation Note
If wheels or rotors were swapped or removed, ensure the speed sensor magnet or speed sensing ring was properly reinstalled.
Failure to reinstall the speed sensor magnet or speed sensing ring may trigger the E45 error.
Troubleshooting Steps
Step 1 – Disconnect, Inspect, and Clean the Speed Sensor Components
Disconnect, inspect, and clean:
- speed sensor
- speed sensor harness
- speed sensor magnet
After reconnecting all components, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by a loose or dirty connection.
If the issue remains
Inspect the speed sensor system for visible damage.
Step 2 – Inspect for Visible Damage
Inspect the following components for visible damage:
- speed sensor
- speed sensor harness
- speed sensor magnet
If the speed sensor harness is damaged
Replace the speed sensor harness.
After replacement, restart the bike and check whether the E45 code remains.
If the speed sensor is damaged
Replace the speed sensor.
After replacement, restart the bike and check whether the E45 code remains.
If the speed sensor magnet is missing or damaged
Replace or reinstall the speed sensor magnet.
After replacement or installation, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by the damaged or missing component that was replaced.
If the issue remains
Replace the remaining speed sensor communication components.
Step 3 – Replace the Speed Sensor
Replace the speed sensor if:
- the issue remains after replacing the speed sensor harness
- the speed sensor shows visible damage
- inaccurate speed readings continue
After replacement, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by a faulty speed sensor.
If the issue remains
Replace the speed sensor harness.
Step 4 – Replace the Speed Sensor Harness
Replace the speed sensor harness if:
- the issue remains after replacing the speed sensor
- the harness shows visible damage
- communication issues continue after reconnecting components
After replacement, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by a faulty speed sensor harness.
If the issue remains
Replace the speed sensor magnet.
Step 5 – Replace the Speed Sensor Magnet
Replace or reinstall the speed sensor magnet if:
- the magnet is damaged or missing
- the issue remains after replacing the speed sensor and harness
- the wheel or rotor was recently removed or replaced
After replacement or installation, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by a missing or faulty speed sensor magnet.
If the issue remains
Replace the mid-drive unit.
Step 6 – Replace the Mid-Drive Unit
Replace the mid-drive unit if:
- the issue remains after replacing the speed sensor
- the issue remains after replacing the speed sensor harness
- the issue remains after replacing or reinstalling the speed sensor magnet
- communication issues continue after all previous troubleshooting steps
After replacement, restart the bike and check whether the E45 code remains.
If the issue clears
The issue was likely caused by a faulty mid-drive unit.
If the issue remains
Please contact support for further diagnosis.
When To Contact Support
Please contact support if:
- the E45 error remains after completing the steps above
- there is visible damage
- the battery does not charge
- the bike does not power on
- the display does not power on
- the motor does not engage
- the speed reading is inaccurate or missing
- the issue appears related to the speed sensor, speed sensor magnet, harness, connectors, mid-drive unit, or internal wiring
- 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
- you need warranty, repair, replacement part, refund, or replacement support
If the issue remains after this step, please contact our support team and include the photos/videos listed below.
What To Send Support
Please send:
- order number
- Aventon model
- photo or video of the E45 error code
- photo of the display
- photo of the speed sensor area
- photo of the speed sensor magnet or speed sensing ring
- photo of accessible connectors or harnesses, if safe
- photos of visible damage
- confirmation of whether the bike powers on
- confirmation of whether the battery charges
- confirmation of whether the display turns on
- confirmation of whether the motor engages
- confirmation of whether wheel, rotor, or sensor components were recently removed or replaced
- confirmation of whether there was water exposure, crash, impact, modification, or third-party repair
- list of troubleshooting steps already completed
Important Safety Notes
- Do not continue riding if the E45 error remains.
- Do not ride if there is visible damage, overheating, smoke, burning smell, water exposure, or motor resistance.
- Do not open the battery, controller, display, mid-drive unit, 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.