What does Giant SyncDrive error code 21 mean?

The motor lost contact with the rest of the system, and assistance stops Check that the plugs are seated and start the bike again. If the code comes back, your dealer needs to look at it.

Giant SyncDrive · Communication · Service codes (Giant Service Tool, 2020 models)

Giant SyncDrive error code 21

The motor lost contact with the rest of the system, and assistance stops

What you can check

Check that the plugs are seated and start the bike again. If the code comes back, your dealer needs to look at it.

A job for your dealer

Trolda reads live data from Giant SyncDrive bikes. What Trolda shows on your bike

All Giant SyncDrive error codes

Sources

Giant MY20 G-System Service Manual (error code table, pp. 84–85) (2020)

Explained in Trolda's own words from the manufacturer's public documentation. Trolda is not affiliated with the manufacturer. If in doubt, ask your dealer.

Trolda for your e-bike

Trolda connects to your Giant SyncDrive bike and shows what you did, what the motor did, and what it cost the battery.

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Trolda is in open testing on iPhone and Android. You get the app through our tester page, it takes a minute.