BBSHD pedal assist not working but throttle works

[jbtlong]

I was super excited, I got my programming cable and my bike perfected. So I figured why not treat my bike to some of this Mobil 28 grease everyone on the forums is talking about.

i pulled up the Luna cycle bbshd tear down and did everything as best as I could, though I’ll admit the white silicon step was tough.

I patched the bike back and throttle and everything works. But the pedal assist 1-9 doesn’t work! I checked the cables and unplugged and replugged everything several times and I am not color blind.

does anyone have any suggestions ? Everything was working fine and this motor has 300 miles on it. If it means anything I put grease in the nylon gear and that big long spiral metal gear. I don’t think I need a new controller

[Retrorockit]

Check the rear wheel magnet for proper position to the sensor, and if you have a kick stand or center stand be sure the wiring isn't pinched there or some other place.

[jbtlong]

everything was working fine until I opened the motor, my speed is sensed fine with throttle. Its just the PAS not working.

is there a way I could use the multimeter to see if a cable is bad?

[AZguy]

With the controller open you can probe between the gray wire and ground (black wire) that comes from the pedal cadence sensor with a DVM and slowly turn the crank and see the voltage go between about 0V and about 5V

It is also possible to disable PAS operation with programming so you might want to share the programming to make sure that's not the issue

[jbtlong]

I took a photo of the motor right before the incident, but obviously I will have to open it up again. I have attached the programming from today for now and appears normal, I’m using the limitless setting.

I’m going to test out the multimeter suggestion tommorow, are you saying to focus on testing the voltage of the black cable with multiple skinny wires and not the thick cables? I’ve never used a multimeter before.

i removed quite a bit of that white stuff holding the cables in place, once I figure this out should I put caulking or something to seal the controller from the motor?

hopefully some of these pics help, I’ll provide more if needed

[AZguy]

The wires I'm talking about are on the controller side of things - opposite the motor side you have in your pictures... the controller is what looks like it's touching the floor behind the motor next to the sharpie and is easily accessed without removing the motor... there's a four wire (black, red, gray and white) connector that goes from the pedal cadence sensor to the controller. When the connector is still plugged in you can access the contacts in the connector with a multimeter easily. Black is "ground" (0V), red is "V_CC" (~5V) and these supply power to the sensor, gray and white are the signals coming back from the sensor and they switch between ground and V_CC - the gray is the important one...

[jbtlong]

That makes more sense as to which cable to focus on and sort of what I do with the multimeter, but I’m confused on what to do at this point. Do I seperate the black cable with 4 wires? Where does the red and black go, I don’t see a 5 or 0 on the multimeter and it looks like Mayan dialect.

thanks again for the help!

Also I broke the black seal and white silicon on most of the wires. Do I need to reseal that? Last tidbit is the nylon gear, I just spun it and kept it in its chamber and applied Mobil 28 rather than removing the gear and oiling it. Not sure if that would have anything to do with the issue

[AZguy]

Nope - leave them all hooked up - unplugged you can't see anything... On the other side of that black connector you'll see little slots that expose the contacts. You'll want you voltmeter set to volts (DC), turn on the bike and place one lead on the black and the other other on the red and you should see about 5V. Then connect one to black and the other to gray and turn the pedals slowly (you may need a helper) and you should see the voltage go between about 0V and 5V - if so the sensor is working and sending the signal to the controller and the issue more likely lies in the controller, possibly the programming, possibly something else, if not it suggest something's up with the sensor

It's a very easy test so just one place to start

[jbtlong]

There’s no expose slots unless i unplug the black connector

[jbtlong]

BBSHD PAS not working after new Luna controller on electric bike.com forum


The user that posted is Renn and his situation sounds extremely similar to mine. I unfortunately can’t figure out how he solved his problem. It seems like it was his Pas sensor PCB but no idea what he did. Is this something to possibly look into?

[AZguy]

There’s no expose slots unless i unplug the black connector

Sorry, I'm relying on memory and I'm old, likely drink too much and the memory is feeble - what were we talking about?

You can still probe by sticking pins or paper clips into the back of the connectors - be creative ;-}

[jbtlong]

All good bro! Yeah I’m not seeing any exposed cables, but even to jam it in, I’ll contact Luna tommorow and see what they say though.

[AZguy]

I've probed them in the past and it was easy

I still think it's a good idea to see "which side of the pedal cadence connector" your issue is

[jbtlong]

Luna suggested it’s either the controller is bad, or I tugged hard on a wire on the motor side. Do you see anything that stands out to you? Only thing I noticed is a slight discoloration on the copper right above the white tab thing.

as far as probing the controller, is there any videos or pictures demonstrating this?

i can’t seem to find any for anything that looks like a bbshd controller. I’m still not sure how to probe that four wire set.

[AZguy]

Probing the controller PCA directly is very difficult since it's potted... you can probe the motor hall sensor but that's clearly not an issue since the motor runs on throttle... you can also probe the pedal cadence sensor signals easily (haven't done this yet?) and that is the signal pertinent to your issue and probing it will tell you whether the cadence sensor is working properly which is pretty much the only thing I can think of that could cause what you are describing outside the controller... IMO shotgunning the controller is premature until you probe those and if you don't probe them I can't help you much past where we're at....