New bike pedal assist issue

[shauny2801]

Hi I got my first ebike 2 weeks ago all work fine for a week then pedal assist stopped working but throttle still works I've checked all wiring connectors they are ok so can't figure out why? This is my bike from a warehouse clearance not heard of the make but its nice to ride

 

[harryS]

Have you checked the PAS sensor on the pedals? If it is a two piece unit with a separate magnet disk, one common problem is that the disk slipped on the pedals and is positioned too far from its sensor, They can be found on either side of the pedals,

 

[shauny2801]

It's just on the left pedal no separate magnet reading up on this problem could the issue be with the brake sensor?

 

[McCorby]

Wouldn’t expect the throttle to work either if it was a brake switch issue. The brake cutout switch should disable the throttle too when the brakes are applied.

 

[shauny2801]

It's just on the left pedal no separate magnet reading up on this problem could the issue be with the brake sensor

Wouldn’t expect the throttle to work either if it was a brake switch issue. The brake cutout switch should disable the throttle too when the brakes are applied.

The pedal sensor is on left crank but I can't see a magnet anywhere on wheel where else would it be?

 

[harryS]

If it;s a one piece unit, the disk is enclosed in a housing like this one. There's not much to check visually on one of these. I have seem the plastic that grab the axle deteriorate with age, and then they slip and don't turn.

If you still cant find it, show us a picture of the left side of pedals.

There will be a cable coming out of the unit. The electrical check starts by following where the cable connects to the ebike electronics and making sure the connection is intact. If that looks good, then the next step ,if you don't have an electrical background, is to buy an exact replacement, These are fairly common on ebay/amaxon.

 

[shauny2801]

If it;s a one piece unit, the disk is enclosed in a housing like this one. There's not much to check visually on one of these. I have seem the plastic that grab the axle deteriorate with age, and then they slip and don't turn.
View attachment 170771

If you still cant find it, show us a picture of the left side of pedals.

There will be a cable coming out of the unit. The

electrical check starts by following where the cable connects to the ebike electronics and making sure the connection is intact. If that looks good, then the next step ,if you don't have an electrical background, is to buy an exact replacement, These are fairly common on ebay/amaxon.

Mine looks exactly like that I've checked cable all is good there the only thing I have noticed is the casing on the sensor is loose

 

[harryS]

At this point, you can do several things.

-One is to trace the sensor cable to the controller. Unplug it and replug it. Hope that fixes it.
-Another is to check the signals on the sensor while it's connected, with a meter while turning the pedals
-Also another is to buy a new pedal sensor with the same exact connector. See if it works.

It's going to be bad connection, bad sensor, or bad controller.

There are some scenarios where you could have been fooling around with the controller settings and turned off pedal assist. You have to find the manual for your display to see if you did that,

 

[shauny2801]

If it;s a one piece unit, the disk is enclosed in a housing like this one. There's not much to check visually on one of these. I have seem the plastic that grab the axle deteriorate with age, and then they slip and don't turn.
View attachment 170771

If you still cant find it, show us a picture of the left side of pedals.

There will be a cable coming out of the unit. The electrical check starts by following where the cable connects to the ebike electronics and making sure the connection is intact. If that looks good, then the next step ,if you don't have an electrical background, is to buy an exact replacement, These are fairly common

At this point, you can do several things.

-One is to trace the sensor cable to the controller. Unplug it and replug it. Hope that fixes it.
-Another is to check the signals on the sensor while it's connected, with a meter while turning the pedals
-Also another is to buy a new pedal sensor with the same exact connector. See if it works.

It's going to be bad connection, bad sensor, or bad controller.

There are some scenarios where you could have been fooling around with the controller settings and turned off pedal assist. You have to find the manual for your display to see if you did that,

I have taken sensor off I unplugged connection and reconnected it and refit sensor but still nothing pictures of sensor and control panel attached.

 

[harryS]

If you lift the motor wheel off the ground, and turn the sensor with your finger, does anything happen?

You probably want to try a new sensor. There's only three wires in the cable..^5V power, ground, and signal, The signal will toggle between 0 and 5V when the sensor rotates. Some of them have an LED that lights up to indicate they have power, Don;t buy that type unless yours is like that,

 

[shauny2801]

Do you mean when sensor is on crank or like in the picture in my hand? I've ordered a new one anyway just to see if it is a sensor issue

 

[PedalUma]

@harryS is spot on in all regards here. I once worked on one where pedal assist did not work in the lowest power level. There can be weirdness like that as a factor that is not linearly logical in diagnosis. It was a warehouse closeout for a reason.

 

[harryS]

Well it's not working on the crank. Maybe it's slipping. Won't happen with your fingers turning the center section. Make sure your helper has the wheel is off the ground (being an optimist),
.

 

[shauny2801]

Well it's not working on the crank. Maybe it's slipping. Won't happen with your fingers turning the center section. Make sure your helper has the wheel is off the ground (being an optimist),
.

Ye I recon its not turning on the crank it's probably slipping

 

[shauny2801]

An idea maybe I could try is put some electrical tape on the axel then put sensor over that then it won't slip maybe

 

[shauny2801]

Ye I recon its not turning on the crank it's probably slipping

Does it have to fit on crank in a certain direction

 

[PedalUma]

Does it have to fit on crank in a certain direction

Yes, that is very important. The idea of having a friend lift the rear of the bike is very good. That way you can test it with your fingers and mark the left outboard side with tape before installing it.

 

[shauny2801]

At last I've solved it as you say it's slipping on crank I took it off and spun it with my finger and back wheel moved

 

[PedalUma]

Use something like silicone gasket sealant to secure it. That would work much better than tape.

 

[shauny2801]

The new sensor I got was a much tighter fit but the connector was a female not male so I've put silicone on old one to see if it stops it slipping