Pas issue

[Ebikeotis]

Hi guys. Now that I’ve got my wheel working again with new halls my pedal assist has stopped working (it has been working previously). Can they blow? I think I might have plugged mine back in whilst the battery and controller were turned on. If that is the issue are the ones on the net all universal and is there a way to check them like you can with the hall sensors?

 

[HazEbike]

yeah, so if you send us a pic of your PAS connector we can probably guess the pinout, usually, red is 5v, black is GND and white/green/blue/blurple (or any other color literally) is the sense wire. A few steps.

- Make sure PAS is plugged in
- turn controller on
- get multimeter and put in voltage reading mode.
- connect one side to GND
- connect other side to colored or white cable( the third, not 5v cable)

hard part is having a third hand turn the pedal, you should see voltage change from 5 to 0. this is for a 3 pin wired PAS similar to throttle wiring.

if this works, then it may be a setting or your controller. if it doesnt, then either its not a 3 wire, uses some other weird method to judge PAS(or torque sensing?) or it may just be dead due to a bad all sensor in the PAS or demagnetized magnets(unlikely as this happens under high heat and PAS is probably one of the coldest components on an e bike.)


Edited due to typo requesting use of continuity mode.(thanks amberwolf)

 

[Ebikeotis]

yeah, so if you send us a pic of your PAS connector we can probably guess the pinout, usually, red is 5v, black is GND and white/green/blue/blurple (or any other color literally) is the sense wire. A few steps.

- Make sure PAS is plugged in
- turn controller on
- get multimeter and put in continuity mode.
- connect one side to GND
- connect other side to colored or white cable( the third, not 5v cable)

hard part is having a third hand turn the pedal, you should see voltage change from 5 to 0. this is for a 3 pin wired PAS similar to throttle wiring.

if this works, then it may be a setting or your controller. if it doesnt, then either its not a 3 wire, uses some other weird method to judge PAS(or torque sensing?) or it may just be dead due to a bad all sensor in the PAS or demagnetized magnets(unlikely as this happens under high heat and PAS is probably one of the coldest components on an e bike.)

Thanks for the reply. I’ve tried the continuity test and it seems it’s broken. Can I just buy any 3 pin one to replace the one I have? Connection is a 3 pin black red and a colour

 

[HazEbike]

Yeah 3 pin pas should work. Just make sure red to red black to black and color to color and you should be good. Seems like its a hall sense one.

 

[amberwolf]

- get multimeter and put in continuity mode.
<snip>
you should see voltage change from 5 to 0.

Hopefully this was just a typo, but in case you didn't know this:

Continuity mode is not for testing voltage. You can actually damage your meter by measuring voltage with it set to continuity (the cheap ones often have no protection against wrong connections). This mode outputs a small voltage on it's leads in order to do the continuity test, and if a higher voltage is present across the points it's connected to, it may damage this function (sometimes more than just this one).

Continuity is only for checking *unpowered* wires (or diodes, etc), to see if they have a connection.

So I would recommend reinstructing the OP on how to do the test correctly with it set to DC Volts, on the 20V range (unless the meter is autoranging), as his report that the test failed isn't valid, as the voltage test hasn't been done yet.


If his PAS sensor actually is bad, then he should also be made aware that they are not all universal. There are several kinds, with different kinds of outputs, and some controllers will not work with all of them. So most of the time any random sensor should work...they don't always.

 

[HazEbike]

Thank you amberwolf for chiming in.

T'was a typo, had a secondary train of thought going on for testing a different thing.

While they are not universal, a three wire pas is typically a hall sensor due to the engineering limitations of the package size, no?

3 pins 1 for 5v, one for Sense, and one for GND seems most likely, just not guaranteed.

What is the best option?


Also, incase ive been unclear, retest your PAS ebikeotis. My mistaken choice of mode for your multimeter may have yielded a false positive on a bad PAS.


Edit: forgot my manners.

 

[amberwolf]

While they are not universal, a three wire pas is typically a hall sensor due to the engineering limitations of the package size, no?

3 pins 1 for 5v, one for Sense, and one for GND seems most likely, just not guaranteed.

While they do indeed usually use a hall sensor to read the magnet passes, they may have other electronics in there too. In those cases they output something other than a simple pulse everytime the magnet passes.

THe most common type I've seen / read of sends simple pulses whenever a magnet passes in the forward direction, but doesn't output anything when the pedals are rotated backwards. So it matters which way the sensor *and* the ring are mounted, and there are left-crank and right-crank versions. Some people have gotten the one to work on the other side, and some haven't; it's not clear why.

Some sensors output a pulse regardless of direction.

Some sensors output a different pulsetrain for forwards vs reverse. Depending on the kind of pulsetrain and how the controller works, they may still work with a controller that requires a simple pulse whenever magnet passes. But the controllers that use this type probably wont' work correctly with the other kind as they don't get the data they need.

Some sensors output a kind of PWM instead of a simple pulsetrain, so the pulse is just shorter (or longer) the faster you pedal.

There are some threads around here that discuss them, but it's tough to find the specific posts because "PAS" is everywhere, as is "sensor", and the search engine sucks.

 

[HazEbike]

That provides a ton of insight as I was sure there were other ways to do PAS but I wasnt sure what other types of signals could be sent out.

Id be leery of a pas sensor that fires the same pulse forwards or backwards as it reminds me of when I mounted my PAS on the wrong side of my bike, it gave me quite the wallop when I tried to line the pedals up in a stop. .

I've noticed the search issues, been trying to compensate by using terms and adding "endless sphere" on the end in regular google, or using the built in google search option.

I appreciate the wealth of knowledge that you and the other guys have to offer here as it's been helpful on my first e bike build even if the search sucks sometimes

 

[HK12K]

You can actually damage your meter by measuring voltage with it set to continuity...

Can confirm. Once tested a 240v circuit with the meter accidentally set to 200k Ω. Meter exploded in my hands. Never made that oversight again. :lol: