Yamaha pwx3 just stopped working!!

My 2 year old haibike allmtn 10 with Yamaha pwx3 motor stopped working yesterday. The display is lit and it changes modes. I unplugged the 2 wire power cable to motor and IAM getting 38 volts there. Not sure wether to pull motor out and open it up. I've only done about 500 miles from new so looks like new still. Any suggestions greatly appreciated.

Nosbod007 said:

My 2 year old haibike allmtn 10 with Yamaha pwx3 motor stopped working yesterday. The display is lit and it changes modes. I unplugged the 2 wire power cable to motor and IAM getting 38 volts there. Not sure wether to pull motor out and open it up. I've only done about 500 miles from new so looks li...

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38V at the motor plug tells you the battery and its wiring are fine - the fault's downstream of that connector, not upstream. So don't waste time chasing the battery end; it's doing its job.

The lit display cycling modes is just the display doing its own thing off USB-ish power from the loom - it can stay perfectly happy even if the drive unit itself has flagged a fault and shut down.

The real diagnosis on a PW-X3 needs Yamaha's diagnostic tool plugged in to pull an actual fault code, because "motor gets voltage but does nothing" covers everything from a dead controller board to a tripped internal cutoff to a corroded pin inside the connector itself.

Given it's a 2-year-old bike with only 500 miles on it, I'd hold off pulling the unit apart.

A couple of reasons:

• If it's still within Yamaha's motor warranty window, opening the case yourself is likely to void any claim - worth getting a Haibike dealer to confirm warranty status before you touch a single screw.

• Diagnosing a dead PW-X3 from the outside with a multimeter only gets you as far as "power's present" - you've already proven that.

Anything past that (controller fault, internal comms) genuinely needs Yamaha's own diagnostic software, which dealers have and home mechanics generally don't.

Worth also checking the connector itself for corrosion or a bent pin while it's unplugged - low mileage but two years is plenty of time for damp Peak District weather to get into a poorly-seated connector, even if the rest of the bike looks showroom fresh.