Aventon Mid-Drive Bikes – E42 Motor Fault TroubleshootingUpdated 2 days ago
This article explains how to troubleshoot the E42 “Motor Fault” error on Aventon mid-drive bikes.
Use this article if your bike:
- Shows error code E42
- Displays “Motor Fault”
- Experiences motor performance issues
- Has intermittent motor operation
- Does not properly engage motor assistance
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 E42 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, 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
E42 indicates a motor fault involving the mid-drive motor system.
The issue may be caused by:
- an internal motor warning or error
- damaged motor components
- damaged display or motor communication wiring
Possible Causes
- internal motor warning or error
- damaged motor
- damaged display-to-mid-drive harness
- damaged internal motor-to-controller cable
- worn cable
- broken connector
- internal open circuit
Troubleshooting Steps
Step 1 – Disconnect, Inspect, and Clean the Mid-Drive Motor Connections
Disconnect, inspect, and clean:
- mid-drive motor assembly
- motor connections
- display harness connections
Ensure there are no obvious signs of damage.
After reconnecting all components, restart the bike and check whether the E42 code remains.
If the issue clears
The issue was likely caused by a loose or dirty connection.
If the issue remains
Inspect the mid-drive unit and display harness for visible damage.
Step 2 – Inspect for Visible Damage
Inspect the following components for visible damage:
- mid-drive unit
- display harness
If the mid-drive unit is damaged
Replace the mid-drive unit.
After replacement, restart the bike and check whether the E42 code remains.
If the display harness is damaged
Replace the display harness.
After replacement, restart the bike and check whether the E42 code remains.
If the issue clears
The issue was likely caused by the damaged component that was replaced.
If the issue remains
Replace the remaining communication component.
Step 3 – Replace the Display Harness
Replace the display harness if:
- the issue remains after replacing the mid-drive unit
- the harness shows visible damage
- communication issues continue after reconnecting components
After replacement, restart the bike and check whether the E42 code remains.
If the issue clears
The issue was likely caused by a faulty display harness.
If the issue remains
Replace the mid-drive unit.
Step 4 – Replace the Mid-Drive Unit
Replace the mid-drive unit if:
- the issue remains after replacing the display harness
- the motor shows visible damage
- the motor fault continues after reconnecting components
After replacement, restart the bike and check whether the E42 code remains.
If the issue clears
The issue was likely caused by a faulty mid-drive unit.
If the issue remains
Replace both the mid-drive unit and display harness.
Step 5 – Replace the Mid-Drive Unit and Display Harness
Replace:
- the mid-drive unit
- the display harness
After replacement, restart the bike and check whether the E42 code remains.
If the issue clears
The issue was likely caused by a communication failure between the motor and display system.
If the issue remains
Please contact support for further diagnosis.
When To Contact Support
Please contact support if:
- the E42 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 issue appears related to the motor, display 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 E42 error code
- photo of the display
- photo of the battery area
- 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 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 E42 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.