Aventon Mid Drive – W108 / W109 Bike Lock Failed TroubleshootingUpdated 2 days ago
This article explains how to troubleshoot the W108 and W109 Bike Lock Failed errors on Aventon mid drive eBikes with an ACU/ECU (Aventon Control Unit).
Use this article if your bike:
shows a W108 or W109 error code
cannot engage or release the bike lock correctly
has a kickstand lock or hub lock issue
shows a bike lock warning in the display or Aventon app
If you are unsure about any step or anything looks unsafe, stop and contact support before continuing.
Before You Start
Please prepare the following before troubleshooting:
your order number
your Aventon model
a photo or video of the W108 or W109 error code
a photo or video showing the bike lock issue
when the issue first appeared
confirmation of whether the bike powers on
confirmation of whether the display turns on
confirmation of whether the lock mechanism engages or releases
confirmation of whether the issue started after transport, storage, water exposure, impact, crash, modification, software update, or third-party repair
photos of any visible damage
Safety Warnings
Do not continue riding if the bike has a persistent error code.
Do not continue riding if the lock mechanism appears damaged or obstructed.
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 about any step.
What This Error Means
The W108 and W109 errors mean the bike lock system has failed or cannot operate correctly.
This may happen if:
the bike is moving while the lock is engaging
the lock mechanism is obstructed
the lock position is incorrect
there is a software issue
the lock system or controller has a fault or connection issue
Possible Causes
Possible causes include:
the bike is in motion while locking
the lock mechanism is blocked
incorrect lock position
software issue in the ECU version
damaged bike lock
damaged ECU
disconnected controller
damaged controller
Troubleshooting Steps
Step 1 – Make Sure the Bike Is Stopped and the Lock Mechanism Is Clear
Ensure the bike is fully stopped before using the lock feature.
Check that the lock mechanism is not obstructed.
Kickstand Lock
Lower the kickstand fully into the correct position.
Then try to re-engage the lock.
Hub Lock
Gently rock the bike forwards and backwards.
Then try to re-engage the lock.
If yes
If the lock now operates normally and the error clears:
continue monitoring the bike during normal use
If no
If the lock still does not operate correctly or the error remains:
continue to Step 2
If the issue clears
The issue was likely caused by lock position, movement, or an obstruction preventing the lock from engaging correctly.
Continue monitoring the bike.
If the issue remains
Continue to Step 2.
Step 2 – Check for Visible Controller Issues
Inspect accessible areas around the controller and visible wiring for:
obvious disconnection
visible damage
loose accessible connectors
Do not open sealed components or disconnect internal wiring.
If yes
If you can see visible damage or a disconnected accessible connector:
do not continue riding
please contact our support team with the photos and videos listed below so we can review the next step
If no
If there is no visible damage or disconnection:
continue to Step 3
If the issue clears
If the issue clears after checking accessible connections:
continue monitoring the bike during normal use
If the issue remains
Continue to Step 3.
Step 3 – Update the ACU Software Using the Aventon App
Open the Aventon app and check for available ACU software updates.
If updates are available:
update the ACU software to the latest version using the Aventon app
keep the bike powered on during the update process
do not disconnect the app during updates
After the update:
restart the bike
reconnect the bike to the Aventon app
check whether the W108 or W109 error remains
If yes
If the error clears after the update:
continue monitoring the bike and lock function during normal use
If no
If the error remains after updating:
continue to Step 4
If the issue clears
The issue was likely related to software communication or lock system control.
Continue monitoring the bike.
If the issue remains
Continue to Step 4.
Step 4 – Check Whether the Error Persists
After completing the previous steps, check whether the lock system still fails or whether the W108 or W109 error remains active.
If yes
If the error still remains:
stop using the bike
please contact our support team with the photos and videos listed below so we can review the next step
If no
If the error no longer appears:
continue monitoring the bike during normal riding and locking
If the issue clears
The issue may have been caused by lock positioning, obstruction, connection, or software communication.
Continue monitoring the bike.
If the issue remains
Please contact support.
When To Contact Support
Please contact support if:
the W108 or W109 error remains after completing the steps above
the lock mechanism will not engage or release correctly
there is visible damage
the bike does not power on
the display does not turn on
the issue appears to involve the controller, ECU, lock assembly, connector, cable, or internal wiring
the bike has been exposed to water, crash damage, impact, transport damage, modification, or third-party repair
you are unsure how to safely complete any step
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 the following:
your order number
your Aventon model
a photo or video of the W108 or W109 error code
a video showing the lock issue
a photo of the display
screenshots of the Aventon app, if relevant
photos of the lock mechanism area
photos of accessible connectors, if safe and visible
photos of any visible damage
confirmation of whether the bike powers on
confirmation of whether the display turns on
confirmation of whether the lock mechanism engages or releases
confirmation of whether the issue started after transport, storage, water exposure, impact, crash, modification, software update, or third-party repair
confirmation of which troubleshooting steps you have already completed
Important Safety Notes
Do not continue riding if the W108 or W109 error remains.
Do not ride the bike if the lock mechanism is not operating correctly.
Do not ride the bike if there is visible damage, overheating, smoke, a burning smell, or water exposure.
Do not open the battery, controller, ACU/ECU, or sealed electrical components.
Do not force connectors or lock mechanisms.
Do not work on wiring while the bike is powered on or connected to the charger.
Contact support if you are unsure about any step.