Shimano STEPS error W965: Drive unit and can device mismatch
The drive unit has detected a CAN-connected accessory or component that is not compatible with it, so it flags a compatibility warning rather than a hard fault. As a result the bike typically cuts motor assist, walk assist stops working, and the speed reading may freeze. Power still comes on so lights and the display remain live, but the rider has no pedalling support until the mismatch is resolved.
| Drive system | Shimano STEPS (E5000, E6100, E7000, E8000, EP6, EP801) |
| Severity | Warning |
| Keep riding? | Ride with caution |
| Typical cost | A diagnostic and firmware update is typically included in a service (0-40 EUR); a compatible replacement CAN device such as a display or switch generally costs 40-180 EUR, and a full junction or wiring harness replacement can run 80-260 EUR fitted. |
Likely causes
- Aftermarket or non-Shimano CAN device fitted to the system (third-party display, GPS unit, or e-bike lock).
- Firmware version on the drive unit does not match the firmware on the CAN device after a partial update.
- Drive unit or junction replaced with a unit from a different Shimano STEPS generation (e.g. E6100 paired with an EP801-era display).
- Damaged, bent, or corroded pins in the CAN connector or E-Tube wiring harness.
- Loose CAN plug at the drive unit, junction, or switch.
- Genuine Shimano accessory fitted but not yet registered or paired through E-Tube Project.
- Battery-side or accessory-side CAN termination issue after a recent service.
How to fix Shimano STEPS error W965
- Stop the bike, switch the system off, and power it on again after 30 seconds to confirm the warning is not transient.
- Unplug any aftermarket accessory connected to the CAN/E-Tube port and retest; a non-Shimano unit is the most common cause.
- Inspect every CAN plug along the wiring harness for bent pins, pushed-in contacts, dirt, or green corrosion; clean with contact cleaner and reseat firmly.
- Confirm that every component in the CAN chain is a genuine Shimano part listed for your drive unit generation; swap any suspect unit for a known-good genuine one.
- Connect the system to Shimano E-Tube Project (dealer or workshop version) and run the firmware update on both drive unit and CAN device so the versions match.
- If the warning persists, the connected device is not electrically compatible with the drive unit and must be replaced with one Shimano lists for that system.
- Book the bike with an authorised Shimano dealer so they can read the diagnostic log, confirm compatibility, and source or programme the correct CAN device.
Warranty: Compatibility and firmware faults on genuine Shimano components within the standard two-year warranty are normally covered as manufacturing defects, but damage from non-genuine accessories, water ingress, crash impact, or unauthorised modification is excluded.
Typical cost: A diagnostic and firmware update is typically included in a service (0-40 EUR); a compatible replacement CAN device such as a display or switch generally costs 40-180 EUR, and a full junction or wiring harness replacement can run 80-260 EUR fitted.
Frequently asked
Can I reset Shimano error W965 myself?
No. There is no user reset that clears W965. The warning reappears at power-on until the incompatible device is removed or the firmware on both ends is matched through E-Tube Project.
Is it safe to keep riding with W965?
Yes, but only without motor support. The bike still rides and brakes normally, so you can roll home carefully or to a workshop, but assist and walk mode are disabled until the mismatch is fixed.
How much will the W965 repair cost and is it under warranty?
On a stock bike with genuine parts inside two years the firmware update and any genuine CAN device replacement are usually covered at no cost. Outside warranty expect 40-180 EUR for a compatible CAN device plus a workshop labour charge of around 30-60 EUR.
Related Shimano STEPS codes
Manuals and video
Official source: si.shimano.com
Not an official Shimano STEPS document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.