Problem with PAS

Hello there lads,

So long story short I bought a OUXI v8.2 fatbike for myself to get to work with since I am not a driver and I work like 10km away from my place but after a couple of months using this bike which is amazing for the price I must say I started receiving problems with the PAS. Happened like a week ago for the first time coming back from a place I went to which was a bit uphill so the bike was struggling even with full pedal assist so I thought maybe it got tired or something haha (not really a bike guy) what happened was that the pedal assist would randomly turn off and after a couple of minutes turn on again then I discovered sometimes it turns off after I use brakes, anyway after a couple of days doing that the pedal assist won't turn on at all, I've watched some videos and guides ok how to fix that issue but with no success, I've checked the sensor which seems to be working because it blinks red when pedaling forward as it used to but the motor is not engaging, I tried with a new sensor but the new one did not turn on at all, no blinking whatsoever. So I am kind of lost at the moment and would appreciate any help or advice.


Thank you for your time.

Does the bike have a throttle, and does that work? If it doesn't have a throttle, is there a walk mode that works? You want to determine whether it's the motor or the PAS system.

A lot of PAS sensors don't use LED's, but if the replacement has one and it doesn't work, it's either defective or has a different wire pin-out in its connector,.

docw009 said:

Does the bike have a throttle, and does that work? If it doesn't have a throttle, is there a walk mode that works? You want to determine whether it's the motor or the PAS system.

A lot of PAS sensors don't use LED's, but if the replacement has one and it doesn't work, it's either defective or has a different wire pin-out in its connector,

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Has no throttle no, there is a walk mode as far as I know but i've never used it so I cannot really tell if it works, I've tried it and I don't think I feel a difference so unless it's super small help I don't think that works either. Actually I don't think the replacement has one.

Because the old PAS started misbehaving and a brand new didn't turn on at all I'd say it's likely a controller issue. The odds are slim that both PAS suddenly started malfunctioning out of the blue or were delivered bricked from factory.

The bike has no throttle? Then perhaps time to order a right thumb throttle. Every ebike controller out there should have a connection for it I doubt yours are any different. As long as you can access the controller have a look what kind of pins they use (3-pin male/female) and order one that suits your bike.

Walk mode spins the motor. Lift the wheel off the ground.

docw009 said:

Walk mode spins the motor. Lift the wheel off the ground.

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Nothing happens

“then I discovered sometimes it turns off after I use brakes”

Does your bike have brake switches? If so it would be a good idea to disconnect them when you are diagnosing the problem.

AGS said:

“then I discovered sometimes it turns off after I use brakes”

Does your bike have brake switches? If so it would be a good idea to disconnect them when you are diagnosing the problem.

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I don't think they do. So far people said the sensor is working it's either the controller or the motor. How can I troubleshoot those 2?

CabbageCat said:

I don't think they do. So far people said the sensor is working it's either the controller or the motor. How can I troubleshoot those 2?

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Most likely there are cutoffs, since it’s a factory bike with PAS. Plus the replacement brake levers on their site clearly have cutoffs. I would unplug those while troubleshooting, as suggested, since it sounds like it could be the issue.

E-HP said:

Most likely there are cutoffs, since it’s a factory bike with PAS. Plus the replacement brake levers on their site clearly have cutoffs. I would unplug those while troubleshooting, as suggested, since it sounds like it could be the issue.

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What do I unplug sorry ? I'm not really good with these things.

Look at you brake levers and trace the wire down until you find a small plug. Then unplug both sides.

This will remove the brake switches to eliminate them while you are fault finding your pas problem.

Your initial post suggests this could be the problem.

Based on the length of the cable in the photo, you likely will trace it all the way to the controller which from photos of the bike, may be located under the seat.

By the way, PAS should always stop assisting when pulling the brake lever; which is a safety feature.
“then I discovered sometimes it turns off after I use brakes”

E-HP said:

Based on the length of the cable in the photo, you likely will trace it all the way to the controller which from photos of the bike, may be located under the seat.

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By the way, PAS should always stop assisting when pulling the brake lever; which is a safety feature.
“then I discovered sometimes it turns off after I use brakes”

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What I meant was that the pedal assist would not turn on after using brakes.

CabbageCat said:

What I meant was that the pedal assist would not turn on after using brakes.

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That’s what happens when there is a faulty brake switch, which is why we are suggesting you disconnect both brake switches.

After unplugging one of the brakes the motor engages again, thank you all for the tips and the help, really appreciate it!!!