W003
What code W003 means on a Shimano electric bike, what causes it, and which part to check first.
● SEVERITY: MEDIUM
Shimano W003 means: Battery temperature warning. The documented cause is:
What W003 means
Battery temperature warning
The display shows W003 and the machine stops until the fault is cleared.
Replacement parts
Tools you'll need
Worth repairing, or worth replacing?
The battery: how long it lasts, when to replace it, what it costs
Before you open anything
Switch the system off and remove the battery before opening any connector. A traction battery stores enough energy to melt a tool and start a fire, and a damaged cell can ignite hours later. Never charge a swollen, dented or wet battery, and never leave one charging unattended.
What to check, in order
From the quickest check to the one that needs a technician.
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Frequently asked questions
What does W003 mean on a Shimano?
Battery temperature warning The documented cause is:
Can I fix W003 myself?
It depends on the part involved: Clearing a filter or straightening a hose is within reach of anyone; anything behind a panel means mains electricity and water together — that is a job for a technician.
Can I keep riding with this code showing?
Yes: we document 18 other codes for Shimano on this electric bikes. They are listed at the bottom of this page, each with its own meaning.
Does the same code mean the same thing on other brands?
Often not. The same two characters can point to completely different faults depending on the manufacturer — always check the page for your own brand.