I bought a Pure Flux One as a “factory second” from a local trader for less than half RRP, and he was clear from the start that it had a month’s warranty. I really like the look of the bike, the low maintenance belt drive, its light weight and disc brakes. It was fine for a few months but then started showing a ‘speed sensor’ error on the LCD control unit.

I removed the sensor by the crank arm and cleaned that and the wiring plugs up but sadly it didn’t help. I couldn’t seem to find where to buy spare parts for the Pure Flux One in the UK, and Pure no longer sell the ebike or have retail shops of their own. The local ebike specialist PoweredBicycles has fixed a few of these (all bought from the same guy!) but advised it can be time intensive to find the part causing the fault.

Pure Flux One ebike pedal sensor location

Pure email support were helpful however and could sell me a new pedal sensor (marked P14L), and gave me the new distributor TGC’s contact details for further help. TGC were also helpful and sold me a pedal sensor (£10) and brake pads (£5ish) which arrived quickly.

Changing the sensor was easy enough – using a crank puller and a 16mm spanner I removed the left crank arm and the sensor was loose so came straight off. The connector was inside the frame on the main loom. The new sensor fitted more snugly and I added a tie wrap to keep it from coming away from the bottom bracket again. Sadly the new pedal sensor didn’t fix the error though.

After more test rides I’ve found the following:

• The speedo says 00 at all times
• When pedalling the motor comes on for a few seconds and then the “speed sensor” error appears and the assist cuts out
• It has a “cool-down” when pedalling stops, the error disappears and then the above repeats when pedalling again
• Under ‘battery info’ in the LCD settings screen, the battery voltage shows as 41.5v when fully charged, but capacity shows 0% and current 0a
• The LCD unit won’t turn off, and gets stuck on the “Pure” screen – have to unplug the LCD or remove battery to turn it off

The Pure Flux One ebike pedal sensor is similar to this and is marked P14L

TGC suggested some troubleshooting advice to check battery voltage and sent me the manual for the display. Battery voltage was fine at around 42v thankfully. They also offered a controller and LCD display on sale or return so I can try those out which is very useful.

To be continued…