The dreaded Error 30 (communication error) [Resolved]

[rick_p]

I'm helping a neighbor diagnose his bike, which displays an Error 30 a few moments after you power on the bike. I found dozens of posts about this particular error across several websites, videos on YouTube, and a troubleshooting guide on the bike manufacturer's website. So, I really didn't think I would need to ask for help here, but I have tried everything I can think of, so I'm seeking suggestions.

Bike: 2018 AddMotor folder with 20" wheels.
Motor: Bafang 500w rear hub motor
Display: AddMotor branded but I'm about 99% sure it's a Kingmeter SW-LCD
Controller: Lishui LSW 1250
Battery: 48v

What I've tried thus far:

• Per the manufacturer's troubleshooting guide, I disconnected everything, then connected only the battery and LCD to the controller and turned it on. Same error, so that rules out brakes, throttle, light, and motor.
• Since the most frequent cause of this error is wiring, I removed the harness from the bike and verified each pin of the LCD connector (display end) has continuity (at least 5 ohms resistance) at the controller end of the cable with no short circuits to other pins.
• I changed the controller to a newer model, with only the battery and LCD connected and turned it on. Same error, so that sort of rules out the controller unless it just instantly fried a second controller. (as it turns out, that is not a definitive test. In the end it turned out that the display and the original controller were both fried, so getting the same error with the new controller did NOT rule out the original controller also being bad. Note added after resolution.)
• I didn't have a spare Kingmeter SW-LCD but I did have a spare SW900 so I wired that up. It displayed an Error 10, which is also a communication error a few moments after I powered on the bike. (Not a good test though, not all displays work with all controllers. Note added after resolution.)
• I reconnected the original LCD and did the reset procedure on it (simultaneously hold up and down buttons) and reset all the settings to what seemed like default settings. No difference, same error 30.

It may be worth mentioning that if I connect the throttle and motor cables, the motor works until the display shuts itself off and kills power to everything.

Any and all guidance/suggestions is greatly appreciated. Thank you in advance.

 

[amberwolf]

You may want to post your excellent troubleshooting findings and READINGS in a more direct thread post to help other true electron chasers with correct voltage display readings.

Here in the Ebike Troubleshooting section, you can also mark a post as the solution to the problem, and it retitles the thread SOLVED: (thread title) and shows that post to readers, which effectively does the same thing.

Just make a summary post of the things you want to be in that solution post, and then mark it as the solution.

 

[rick_p]

Was afraid of that, but hey worth a try. For verification, nothing worked? No speed, battery power, or other usable information displayed?

Correct, everything displays for a few moments and then it switches to Error 30, then turns itself off.

The key would be being stuck in the one level of PAS. I don't know of a work around without a communicating display...
Some systems will stick the controller a certain PAS level with display configuration. Then you can remove and bypass. Some people like a "stealth" mode.

To your point, the throttle is limited to 20mph, and whatever level the PAS is stuck in is the same or very close. The owner‘s response to this news was “Beats the hell out of being dead in my garage.” I can’t argue with that, I rode it and it’s felt pretty good to me. Sure, it could be a little faster, but 20mph is not slow.

Since it does stay on for 20 seconds or so, I wonder if I could pump the PAS level up to the top before the error comes on and then remove and bypass . Definitely worth a try.

I would encourage you not to leave the display with a toasted component wired into the system. Just use the bypass jumper.

I didn’t even mount it for the test and immediately removed it when it failed, but thanks for the tip!

You may want to post your excellent troubleshooting findings and READINGS in a more direct thread post to help other true electron chasers with correct voltage display readings.

It’s the least I can do. I was thinking there is some confusing and even incorrect information in the middle of the post, so yeah, a nice concise post with the good troubleshooting and readings is a good idea, I’ll tag you so you can proof it.

Glad to help out. Thanks for taking me along for the ride.
Best regards,
T.C.

 

[rick_p]

Here in the Ebike Troubleshooting section, you can also mark a post as the solution to the problem, and it retitles the thread SOLVED: (thread title) and shows that post to readers, which effectively does the same thing.

Just make a summary post of the things you want to be in that solution post, and then mark it as the solution.

Sounds good

 

[rick_p]

A Summary of this entire thread, with links to key information when diagnosing an Error 30:

I read through the entire thread and added notes and corrections wherever possible to help prevent misleading anyone trying to diagnose their bike for an Error 30 condition.

Key Post: KT and Lishui wiring sequence diagram, and voltage readings indicating abnormal reading on Yellow (TX) wire.

Next post is also good, it shows both KT, Lishui, and Bafang) configurations. Pay attention to male vs female configurations.

Helpful post if you're working on an Add Motor bike with proprietary harness and controller.

Helpful post if you're working on an Add Motor bike with proprietary harness and controller. Same as previous but has voltages from suspected bad controller.

This post provides the pin voltages on the new controller, note that only the battery wire has voltage, none of the other wires do. Now whether that is just a difference between the two controllers is unknown, but the high voltage on the Yellow (TX) wire makes the original controller suspicious, so I never attempted using a jumper to bypass the display with that controller for fear that I might damage something else, especially after opening the display and finding the blow out. It's entirely possible that only the display circuitry is bad, and the controller might still operate with the bypass, but I don't intend on doing that test on this bike, I might do that as a bench test in the future sometime, but not on this bike.

There is a long discussion in the thread about taking resistance readings. I learned a lot in that discussion but rather than trying to post links to key note, I'll just post my key take-aways. If you already know how to properly take resistance readings, this is useless information for you.

• Verify that your meter and test leads are working properly before you start, touching the leads together should return infinite, or near zero resistance. If you get some resistance, then you may need to replace you battery or your leads, or both.
• Some meters will auto-range, if you are not paying attention to that, you might be fooled by what you see on the screen (this happened to me). Some meters allow you to set the range with the dial, and some you must use a button to select the range, learn how to set and read your meter.
• Always remember to move your meter leads to the correct ports when going from voltage readings to amperage readings or visa-versa. (I did not know this, but luckily I never tried reading amperages with my meter.)
• Do not test electronic circuits that go past 10,000 volts, you will likely damage your meter. Not really an issue with eBikes, but good to know.

I wanted to mentioned the resistance discussion because it segues into a post where I provide key information that leads to the resolution of the Error 30 in this case. But first I want to mention an important diagnostic around the high voltage in the Yellow (TX) wire, where @TommyCat asks the question if the voltage on that wire might be ghost voltage.

In case you are not familiar with the term “ghost voltages” (I wasn't) they are voltages on a circuit that it might drop to zero if a load is applied (it's actually connected to something).

In this post I properly retest the wiring inside my harness and post the results. Don't underestimate how important this test is. A lot of people go down rabbit holes before testing the obvious things like wires and connectors. And I also post the results of the ghost voltage test. The subsequent posts after this one are good too.

This post merely shows the fried chip on the display's circuit board, which is proof that the display was at least part of the problem, but the post itself is not terribly important in terms of diagnostics.

In the end, it was agreed that the zero voltage readings (at the controller harness) on all pins with the exception of battery power to the display was a good sign that the new controller was good and that the jumper test to bypass the display was safe to try, and it worked, the bike is now operable, albeit without a display, but it's operable. To make the bike like new again would require purchasing a new proprietary display from the bike's OEM, but in this case the owner has decided to ride it without a display because it's expensive and he's not concerned with the bells and whistles in provides, the battery has a key to turn the bike on and off, and has an LED battery charge indicator on it, which is all he cares about.

 

[amberwolf]

Good summary!

 

[TommyCat]

That's a handy feature. Job well done!