HELP KT LCD3 error code 3

[TommyCat]

Just some thoughts...

The Bafang display can be bypassed by jumping the power (P+) to the control (PL) pins. Since your display has Battery positive power in (36v Red wire) and control (Control Blue wire) My theory would be you could do the same. (I have not done this)

Or you could just cut to the chase and verify your motor's hall sensors operation to eliminate them as a problem.

https://www.ebikes.ca/documents/HallSensorTestingFinal.pdf

Just for reference, my BAC-601 display on my Magic Pie v5 uses communication for the battery, speed and distance information. The reason I mention this is it seemed counter intuitive at the time getting the battery voltage this way... and it seems like you might have been trying to get an accurate speed indication.

 

[docw009]

Just some thoughts...

The Bafang display can be bypassed by jumping the power (P+) to the control (PL) pins. Since your display has Battery positive power in (36v Red wire) and control (Control Blue wire) My theory would be you could do the same. (I have not done this)

Or you could just cut to the chase and verify your motor's hall sensors operation to eliminate them as a problem.

That's a great idea to try the bike without the display!

I've received KT controllers shipped with the controller input bypassed. On the 5 pin LCD plug, jumper green and yellow, red and blue. ANd this is what the instructions tell us.




Problem is ..original poster has the modular connector to the LCD3. By the way, it's not a Bafang pinout. They are different.

Here is the best LCD3 manual I've found online.
https://03c9aaa.netsolstores.com/manuals/EBO_KT-LCD3_USER_MANUAL.pdf

It has the default C parameters on the last page, and also shows the pinout for an LCD3 higo connector,
View attachment 1

Let's try it. Not saying it works on other folk's harness, but this works on my mine. I didn't do the data jumper, and I didn't have a PAS hooked up, but throttle works and that's all the OP needs to see if the Hall sensors really are bad.

 

[boeb]

Just some thoughts...

The Bafang display can be bypassed by jumping the power (P+) to the control (PL) pins. Since your display has Battery positive power in (36v Red wire) and control (Control Blue wire) My theory would be you could do the same. (I have not done this)

Or you could just cut to the chase and verify your motor's hall sensors operation to eliminate them as a problem.

That's a great idea to try the bike without the display!

I've received KT controllers shipped with the controller input bypassed. On the 5 pin LCD plug, jumper green and yellow, red and blue. ANd this is what the instructions tell us.

Jumper.jpg


Problem is ..original poster has the modular connector to the LCD3. By the way, it's not a Bafang pinout. They are different.

Here is the best LCD3 manual I've found online.
https://03c9aaa.netsolstores.com/manuals/EBO_KT-LCD3_USER_MANUAL.pdf

It has the default C parameters on the last page, and also shows the pinout for an LCD3 higo connector,
LCD3_pinout.jpg

Let's try it. Not saying it works on other folk's harness, but this works on my mine. I didn't do the data jumper, and I didn't have a PAS hooked up, but throttle works and that's all the OP needs to see if the Hall sensors really are bad.

small_lcd3_jumper.jpg

Thanks guys but this is going a little over my head.. I tried messing with electronics but I just don't have the right experience.
Im thinking of just ordering another LCD3 and see if that works, and if not ill just send it back. Thats not a bad idea right?
Im really starting to think that the problem is with the screen given the inconsistencies and the circumstances in which this code error happened. And ill do the same with the controller if thats not the problem. If it comes down to the motor than damnit but at least this way is easy for me.
Its cool your helping me come up with solutions though! again thanks

 

[TommyCat]

Thanks guys but this is going a little over my head..

Disconnecting the display and jumping two pins to eliminate a bad display seems pretty straight forward. Especially after Docw009 verified it can be done and laid it out so nicely for you. But that's your call.

As far as remove and replace. Yes, for some it's easier and recommended by a lot of people. But I like to try everything I can before giving in. At least to get to the true source of the problem. Say you have a controller or wiring harness that is shorting out. Which causes your display to short out. Swapping the display will only get you another bad display. Which is precisely why I would never intentionally "borrow" a vendors part for testing. Plan on keeping it.

I've received KT controllers shipped with the controller input bypassed. On the 5 pin LCD plug, jumper green and yellow, red and blue. ANd this is what the instructions tell us.

Could you clarify? Was your OEM bypassed controller wired differently than the instructions?

 

[docw009]

I've received KT controllers shipped with the controller input bypassed. On the 5 pin LCD plug, jumper green and yellow, red and blue. ANd this is what the instructions tell us.

Could you clarify? Was your OEM bypassed controller wired differently than the instructions?

No difference. They (PSWpower) put the two jumpers on a JST plug and it was inserted into the LCD connector on the controller.

 

[boeb]

Thanks guys but this is going a little over my head..

Disconnecting the display and jumping two pins to eliminate a bad display seems pretty straight forward. Especially after Docw009 verified it can be done and laid it out so nicely for you. But that's your call.

As far as remove and replace. Yes, for some it's easier and recommended by a lot of people. But I like to try everything I can before giving in. At least to get to the true source of the problem. Say you have a controller or wiring harness that is shorting out. Which causes your display to short out. Swapping the display will only get you another bad display. Which is precisely why I would never intentionally "borrow" a vendors part for testing. Plan on keeping it.

I've received KT controllers shipped with the controller input bypassed. On the 5 pin LCD plug, jumper green and yellow, red and blue. ANd this is what the instructions tell us.

Could you clarify? Was your OEM bypassed controller wired differently than the instructions?

Your probably right. I was actually thinking at the end to go to a shop for a diagnoses but its so expensive! I spent almost all my money already on this bike
I just have a hard time understanding what you are describing but I think Im getting it now and yes it does seem like a straight forward option.
I basically need to disconnect the display and loop the cicuit around directly using this extra electrical wire on the picture bypassing the display..it is indeed a great idea if it works. Ill give it a go, could you give me a link of the wire I need to perform this on the higo connector? Sorry I don't know which terms I need to use.

 

[boeb]

All makes sense now..

 

[boeb]

I think I found the wires I need. Would this do the job or its too thick?

https://www.amazon.co.uk/65pcs-solderless-breadboard-jump-wire/dp/B007T9GUZY/ref=sr_1_4?keywords=jump+wire&qid=1555436240&refinements=p_76%3A419158031&rnid=419157031&rps=1&s=gateway&sr=8-4

 

[E-HP]

I think I found the wires I need. Would this do the job or its too thick?

https://www.amazon.co.uk/65pcs-solderless-breadboard-jump-wire/dp/B007T9GUZY/ref=sr_1_4?keywords=jump+wire&qid=1555436240&refinements=p_76%3A419158031&rnid=419157031&rps=1&s=gateway&sr=8-4

Hey those are fancy :thumb: I was going to suggest a paper clip, if it's just for testing.

 

[boeb]

I think I found the wires I need. Would this do the job or its too thick?

https://www.amazon.co.uk/65pcs-solderless-breadboard-jump-wire/dp/B007T9GUZY/ref=sr_1_4?keywords=jump+wire&qid=1555436240&refinements=p_76%3A419158031&rnid=419157031&rps=1&s=gateway&sr=8-4

Hey those are fancy :thumb: I was going to suggest a paper clip, if it's just for testing.

Wow didn't realize u could do this with just paper clips, I guess its obvious! Im really a newb..
How about guitar string? does it need to be a specific kind of metal?

 

[docw009]

I'll put up a clearer pic. What we're doing is looping the 48V from the battery back into the controller to turn it on. This is what the LCD3 does when we press the center button, although it also activates an internal power supply to power up the LCD and also starts communicating with the controller.

As it is 48V, do be careful with what it can touch. A thin wire is probably better than a paper clip as it will act like a fuse and vaporize if you hook it across the wrong pins. Maybe a paper staple. Those holes are small.

I unplugged the controller when I inserted the jumper. Than plugged it back it. I trust your LCD3 cable is the same as mine.

If you choose not to do it, it's OK. I learned something about the LCD3's round pin out that I didn't know.

 

[boeb]

Not working
I used one of those springy wires that holds the allen keys.. I managed to get it all the way in both holes but no response
I guess the hall sensor really isn't working. God knows how that happened..

 

[TommyCat]

Rats! Sorry that it didn't work for you. But with your determination your one step closer!

The motor actually has 3 hall sensors. And can be checked from the five pin motor connector that connects with the controller.
If you'd like to continue by checking them, post a picture of the connection if possible and we will give you specific instructions on how to test.

Does the wheel still turn easily by hand or is there any resistance with the power on or off?

 

[boeb]

Rats! Sorry that it didn't work for you. But with your determination your one step closer!

The motor actually has 3 hall sensors. And can be checked from the five pin motor connector that connects with the controller.
If you'd like to continue by checking them, post a picture of the connection if possible and we will give you specific instructions on how to test.

Does the wheel still turn easily by hand or is there any resistance with the power on or off?

Thanks TommyCat! But at the end Ive sent the kit back to germany and the company has excepted to do a repair. Shipping was expensive but I should of probably done this from the start. At least i've learned quite a bit trying to solve this. You guys have been amazing with your tips and help!
Will give you guys an update as to what was the actual problem. I'm guessing its probably just the hall sensors and maybe I simply had a faulty unit..

 

[docw009]

Maybe that "light shunt mod" that you mentioned caused all your grief.

 

[boeb]

Hey,

Back with an update.
So yeah most of you were right apparently the cable was broken.. I'm not sure how that happened but at least its fixed now. The motor cables seem to be pretty fragile

 

[dcuste]

I just took delivery on a brand new ebike I purchased on ebay. It came with a hub motor and the KT LCD3 display. The very first time I tried to ride it, the error code 3 came in. I checked all the wires and connectors. They all look good. I then used my voltmeter to verify 5v going to the motor hall sensors between the red and black wires. However when I checked each individual sensor to see if the voltage would pulse up and then down to zero as I turned the wheel, only one of the three sensors worked. The other two showed zero volts to ground the whole time as I turned the back wheel.

Does this test indicate the motor must be disassembled and the hall sensors replaced or fixed? If the seller offers to send me a new motor, should I accept or just return the whole bike?

Edit: the seller offered to send me a new controller. Any chance that will solve the error code 3 problem?

TIA

 

[docw009]

Hey,

Back with an update.
So yeah most of you were right apparently the cable was broken.. I'm not sure how that happened but at least its fixed now. The motor cables seem to be pretty fragile

Great. I didn't see your update when you posted originally, but glad to hear you figured it out!

Me, I've been looking for that spare LCD3 for the past few weeks, because I need it to replace one on a bike that fell over. At least I know I had it back in April.

 

[docw009]

I just took delivery on a brand new ebike I purchased on ebay. It came with a hub motor and the KT LCD3 display. The very first time I tried to ride it, the error code 3 came in. I checked all the wires and connectors. They all look good. I then used my voltmeter to verify 5v going to the motor hall sensors between the red and black wires. However when I checked each individual sensor to see if the voltage would pulse up and then down to zero as I turned the wheel, only one of the three sensors worked. The other two showed zero volts to ground the whole time as I turned the back wheel.
TIA

How well did you probe the Hall wires? Was this on the 9 pin connector (practically impossible to probe unless you go inside the controller) or the 3x2 plastic connector?

On a typical KT controller, the power will read 4.5V red to black, and the three inputs (blue, green, yellow) will read 4.9 volts with the connector open. The inputs go to 5 volts with nothing attached, and the Hall sensor outputs in the motors will pull them down to zero when they flip.

Some motors also put a speed sensor in that connector. It behaves the same way.

Finally, if this is a geared motor, you will only see the Halls working if you spin the wheel backwards. Spinning forward, the motor does not rotate so the Halls are inactive. The speed sensor, if you are probing that, will fire once per revolution, while the Halls fire at the product of the magnets x the gearing. A typical number is 47 times per revolution.

So your info needs to be qualified by whether you actually contacted the wires, whether it was a geared motor, and if so, were you spinning backwards. Not to forget the rapid pulse rate of the Halls.

To determine if it's motor or controller, unplug the connector, power up the controller, and try it again. All of the inputs should be at 5 volts.

 

[dcuste]

Thanks for the reply docw.

It is the 9 pin connector. There are nine wires going to the motor, but the white wire doesn't exist on the controller side of the connector. With the connector disconnected, there is about 4.5v to red and 4.8v to the others.

It is a geared motor and it difficult to hold the bike steady and probe so I'm not sure but now it appears to me that they all pulse up to about 4.8 and drop to 0.08 as I turn the wheelon backwards except the blue wire stays at 4.8v and doesn't drop at all.

I'll run the test again more carefully when I have some help. But if I get the same results, is it a pretty good bet that the problem is either a break in the blue wire going from the connector to the motor or a bad sensor in the motor?

 

[docw009]

I'd agree with that. Sensor problem, either continuity or the component is bad. I don't know of any multimeter tests to help here.

Is it a US seller?

 

[quackstar84]

I'll put up a clearer pic. What we're doing is looping the 48V from the battery back into the controller to turn it on. This is what the LCD3 does when we press the center button, although it also activates an internal power supply to power up the LCD and also starts communicating with the controller.

As it is 48V, do be careful with what it can touch. A thin wire is probably better than a paper clip as it will act like a fuse and vaporize if you hook it across the wrong pins. Maybe a paper staple. Those holes are small.

I unplugged the controller when I inserted the jumper. Than plugged it back it. I trust your LCD3 cable is the same as mine.

If you choose not to do it, it's OK. I learned something about the LCD3's round pin out that I didn't know.

jumper_cable.jpg

Thanks for explaining this. Im having the same error and tried this without any luck. The cable going into my motor which bends inwards looks fine thought. However I cant see inside it of course.

 

[yareq76]

Probably hub motor was overheating and you need to replace hall sensors.