Shimano STEPS error E034: Drive unit firmware fault on Shimano STEPS

Shimano STEPS (E5000, E6100, E7000, E8000, EP6, EP801)Dealer neededDo not keep riding

The motor controller has detected an internal firmware problem inside the drive unit, so the system cuts all electrical assist to protect the electronics. On some display firmware versions the same fault is reported as E013 instead of E034. Pedalling without power is still possible, but walk assist, automatic support modes and any speed-triggered functions are all disabled until the code is cleared.

Drive system	Shimano STEPS (E5000, E6100, E7000, E8000, EP6, EP801)
Severity	Dealer needed
Keep riding?	Do not keep riding
Typical cost	A dealer diagnostic and firmware reflash typically runs 40 to 90 euro, and a replacement drive unit if needed is 450 to 900 euro depending on the STEPS model.

Likely causes

Firmware flash corrupted during a partial or interrupted update
Internal memory or processor fault inside the drive unit
Voltage spike from a failing battery, loose battery mount or bad contact
Moisture or contamination inside the drive unit housing or wiring
Incompatible part fitted after a previous repair or retrofit

How to fix Shimano STEPS error E034

Stop riding and remove the charger from the bike.
Power the system off, wait 30 seconds, then power it back on to see if the code clears.
Reseat the battery and wipe the contacts with a dry cloth so the drive unit gets clean power.
Inspect the visible drive unit cable connectors for moisture, bent pins or green corrosion.
Check on the Shimano E-Tube app or dealer tool whether a firmware update is available for your drive unit.
If E034 returns after a power cycle, take the bike to the place of purchase or an authorised Shimano dealer for a diagnostic reflash.
Do not continue riding with motor assist cut, especially on hills or in traffic.

Go to a dealer if: A Shimano dealer must read the fault log and reflash the drive unit firmware, or replace the drive unit if the memory is unrecoverable.
Warranty: A genuine firmware or internal component fault on a Shimano STEPS drive unit is normally covered by the two year manufacturer warranty, while water ingress, crash damage and aftermarket modifications are not.
Typical cost: A dealer diagnostic and firmware reflash typically runs 40 to 90 euro, and a replacement drive unit if needed is 450 to 900 euro depending on the STEPS model.

Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.

Frequently asked

Can I reset shimano error E034?

A power cycle can clear a transient glitch, but a confirmed firmware fault will not clear without a Shimano dealer diagnostic tool. Trying random button combinations risks corrupting the firmware further.

Is it safe to keep riding with E034?

No. The drive unit cuts assist and walk mode stops working, which is hazardous on hills and in traffic. The system should be checked by a dealer before the bike is used again.

Will Shimano fix this under warranty?

A genuine firmware fault on a STEPS drive unit is usually covered inside the two year warranty. Water damage, crash damage and modified firmware are treated as out of warranty and charged to the owner.

Related Shimano STEPS codes

E013 · Drive unit firmware fault detected E010 · Drive unit internal fault detected E011 · Shimano Steps general system error E015 · Internal drive unit fault detected

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.