PAS anomaly (Kunteng KT-D12L)

[Ocelot]

I purchased a front drive MXUS GDF15 and controller, lcd5 display and a splined PAS sensor.
After installing everything except the PAS sensor, I test rode the bike fine.
The next morning, finishing the job, tidying up the cabling and finding out my BB spindle was too thick to accommodate the spinning portion of the PAS unit.
I pulled it off and installed a split ring magnet assy

and sensor, plugged it in to ensure the controller parameters were set for it. When I powered the bike up and the display immediately indicted “throttle” on the lcd. (It thought the throttle was being activated on power-up). Bike wouldn’t spin the motor.
I disconnected the throttle and powered the bike up again and the display then showed “error 1” (throttle anomaly).
Unplugging the PAS, plugging in the throttle and powering up the bike again showed no codes, no “throttle” flag until I advanced the throttle and the bike worked fine on throttle only.

Has anyone seen this before?

 

[docw009]

One way to get a throttle error on a KT LCD is to power up the display with the throttle slightly cracked open. Sometimes happens if the grip is rubbing against the throttle housing,

Another way is if the PAS connector is wired wrong, and it pulls down the 5V power. I've seen this. Don't recall if there was a throttle error on the display, but like you I had just verified the throttle and speed sensor worked. Then I plugged in PAS and nothing worked.

I've always seen the found three pin Julet connectors on PAS sensors work, but the flat JST connectors seem to be wired any which way,

 

[E-HP]

I purchased a front drive MXUS GDF15 and controller, lcd5 display and a splined PAS sensor.
After installing everything except the PAS sensor, I test rode the bike fine.
The next morning, finishing the job, tidying up the cabling and finding out my BB spindle was too thick to accommodate the spinning portion of the PAS unit.
I pulled it off and installed a split ring magnet assy

and sensor, plugged it in to ensure the controller parameters were set for it. When I powered the bike up and the display immediately indicted “throttle” on the lcd. (It thought the throttle was being activated on power-up). Bike wouldn’t spin the motor.
I disconnected the throttle and powered the bike up again and the display then showed “error 1” (throttle anomaly).
Unplugging the PAS, plugging in the throttle and powering up the bike again showed no codes, no “throttle” flag until I advanced the throttle and the bike worked fine on throttle only.

Has anyone seen this before?

If you plug in the first sensor, even without the disc, does it cause an error?

 

[Ocelot]

One way to get a throttle error on a KT LCD is to power up the display with the throttle slightly cracked open. Sometimes happens if the grip is rubbing against the throttle housing,

Another way is if the PAS connector is wired wrong, and it pulls down the 5V power. I've seen this. Don't recall if there was a throttle error on the display, but like you I had just verified the throttle and speed sensor worked. Then I plugged in PAS and nothing worked.

I've always seen the found three pin Julet connectors on PAS sensors work, but the flat JST connectors seem to be wired any which way,

The display shows “throttle” as soon as I powered the bike up. I was aware that most controllers will not start up properly if the brakes are squeezed or throttle applied when booting up, so that’s what I first thought too.
First thing I did was remove the throttle from the bike and test it when holding it in my hand - some message. Then I swapped it with a known good throttle - same message.
I then unplugged the PAS sensor and everything was fine on throttle only.

The issue is my PAS sensor or the controller settings, but in connecting umbilically, a good one piece “spline type” sensor from a neighbouring bike, everything works fine.

 

[E-HP]

The display shows “throttle” as soon as I powered the bike up. I was aware that most controllers will not start up properly if the brakes are squeezed or throttle applied when booting up, so that’s what I first thought too.
First thing I did was remove the throttle from the bike and test it when holding it in my hand - some message. Then I swapped it with a known good throttle - same message.
I then unplugged the PAS sensor and everything was fine on throttle only.

The issue is my PAS sensor or the controller settings, but in connecting umbilically, a good one piece “spline type” sensor from a neighbouring bike, everything works fine.

If the original sensor doesn't produce an error, then you may have the wrong wiring order on the new once, since you didn't buy the controller and sensor as a set.

 

[Ocelot]

Thank you, I’m appreciating the responses.
Both units are from the same vendor, and his programming sheet sheet says that the C1 setting on the controller should be two or seven depending on the side/direction the units spin. Since the KT – v12L is mounted on the long drive side, the guide said it has to be seven.
His instructions say that the split ring magnetic sensor unit should also be seven or two. I’ve tried both settings.

I know from previous experience that if it’s set wrong, the PIS just simply won’t work, but it doesn’t trigger a fault

I’m very much thinking my split ring sensor just simply went bad

 

[amberwolf]

What voltage do you have for the throttle power supply, with the PAS connected, and without?

If it drops with PAS connected, the PAS is probalby miswired for your system, or damaged.

 

[Ocelot]

I’ll have to find a way to check.
But I’m very convinced that since the one-piece splined PAS works but the split ring magnet one doesn’t, that it is for sure the split mag PAS sensor.

I’ve reached out to the vendor to ask, as he pre-configured the original display/but no replies yet (auto reply is saying possibly 3 business days to respond) hence, is there another controller “C” parameter that should be set for these two different units other than C1?

 

[amberwolf]

Even if there is a setting to make your PAS work, there shouldn't be any way for a setting to cause the throttle to not work with one PAS vs another.

The PAS just wouldn't work, or wouldn't do what you expect, etc.

 

[Ocelot]

Even if there is a setting to make your PAS work, there shouldn't be any way for a setting to cause the throttle to not work with one PAS vs another.

The PAS just wouldn't work, or wouldn't do what you expect, etc.

Exactly

I’m very convinced I should just Amazon a new KT-D12L package and give it a go.

 

[Ocelot]

Bought the amazon PAS assy, installed it and proved my diagnosis was correct!
Onward and upwards!

I merely need to put the controller on the back of the seat tube and I’m good-to-go. (Meaning, further development)

40 km/hr top speed so far.

 

[Ocelot]

So far, I'm very impressed with this conversion.
However, in retrospect, the LBS I bought the front tire from for it suggested I use the largest tire I'd dare since the hub motor made the front wheel considerably heavier - to help avoid pinch flats and possibly give me some ride compliance. So I stepped up from a 700c-28 to a 700c-38. I was a bit concerned about clearance around my "sorta tight fitting" dual pivot rim brake short-reach caliper. It turns out there was just enough adjustment in the caliper to allow it to clear the tire and contact the rim properly. I should have initially spec'ed the hub motor in a 27.5 wheel instead. This would have given me the extra space to install a medium reach or even a long-reach caliper and leave me the option to install fenders down the road.