Power assist keeps cutting out on Giant Trance (Yamaha motor)

Andy B

New member
Local time
10:40 PM
Apr 23, 2024
Plymouth, UK
I've just bought a Giant Trance X Advanced 2022 with a Yamaha engine. On my first trip I found the power assist kept cutting out at very inopportune moments (e.g. when climbing). This happened about 10-12 times during a 3 hour ride. When this happened a single red LED appeared on the display. The only way to get power back was to turn off the system and restart it again.
Can anyone offer any reasons for this please and how to resolve it?
P.S. It wasn't a hot day and the battery wasn't overheating.
I don't own that type of bike, sorry. I would go on Giant's website and download the user manual for your model. You should be able to find out what the led light is intended to represent. That's probably the safest place to start.

The next time it happens check the temp of the motor. Pay attention to what gear you are in and how much leg power you are using on the hill vs how much of the work you are asking from the motor. Those are torque sensing motors, correct? If it's not a technical issue with the bike itself, it could be a battery low voltage cut-off or you could have been in too high of a gear for the hill and pedaling too slowly. Come back and let us know the deets! Good luck!
I bought a 2022 Trance e-3 and had same problem, but never got the red light. The motor would always start again but frustating to be always stopping & starting. Took it back to the shop and the guy adjusted the battery clamp and went well for about a year. Whenever the battery starts cutting out, I just stop trailside, remove battery & reinsert with the bike upright, and tighten it all up and then goes well again. Can't explain the fix but maybe the contacts work loose. Always carry the Torx T25 now.