Yamaha error 66: Controller fault

What it means

The drive unit controller has reported a fault and assist has stopped. Some controller codes clear after a power restart.

Likely causes

• Drive unit controller fault

Symptoms

• Code 66 shown
• Assist stops

How to fix it

1. Turn the power off and on again.
2. If the code comes back, have the bike checked by a Yamaha e-bike dealer.

How urgent is it?

See a dealer if a restart does not clear it.

Applies to

• PW-SE / PW series SE
• PW-X / PW-X2
• PW series TE / CE / ST
• Display X
• Display A
• Display C

More Yamaha codes

• 61 Controller fault
• 63 Controller fault
• 64 Controller fault
• 62 Motor fault
• 67 Motor fault
• 68 Encoder (motor position sensor) fault

All 28 Yamaha codes →