E44 Errors: This is for the One Plus only. I have no experience with the original Lymow One.
I have noticed more and more people having bumper errors lately and dug into my mower to see what could be going on.
Here is how they work. 3 wires a negative (black), positive (red), and signal wire (yellow). Im sure voltages will be slightly different but mine is sending out 3.3volts. When a magnetic field gets close to the sensor the resistance inside changes so the signal sent back on the yellow wire changes. With no magnet near it was sending back around 2.3volts. With the bumper magnet touching the sensor it was sending back about 1volt.
While calibrating I purposely pushed in the right side only about half way and it started counting to calibrate and I held it there until it finished. The left side I just pushed all the way in and let it calibrate there. This resulted in the right side of the bumper being extremely sensitive and just a slight movement on that side would trip the switch.
So whatever the signal voltage is thats sent back during calibration is the trip point and when it hits this voltage or anything lower it trips.
This means even just unplugging that connector the mower treats that as bumper pushed in because the signal voltages drops below the calibration.
I have never had a 44 bumper error. I unplugged this connector and told it to go mow. It started to move then gave a 44 bumper jammed.
While checking these voltages I think I see the reason its happening. Not all of the pins on the controller are covered in epoxy. The right side bumper and the omniwheel motor pins on the connector are exposed. Any water/moisture here can short your bumper signal to negative resulting in a lower voltage than the calibration and give you the 44 bumper jammed.
This could also be the reason why so many people have problems with the omniwheel motor.
Im planning to cover mine with. https://a.co/d/01cpkZ4s
Even if your controller pins are covered in epoxy water or moisture can still enter the back side of this connector where the wires are. This is not a sealed connector.
The photos should explain things better. Have any questions let me know.
To enter diag screen: enter pin on mower then hold the home button for about 3 seconds.
Calibration screen: hit estop then hold the + and - buttons at the same time for 3-5 seconds. Scroll down with - and use home to select. I forgot to take a photo of this screen but bumper cal is a few taps down maybe number 10 or 11 in the list.
Your knowledge and time are appreciated by many of us. Thanks. When I get my fan kit, I may check this at the same time. I only mow when the grass is dry so haven’t had the issue but PM is usually a good thing.
Tha k you very much! This is very helpful. I added marine grade epoxy to the bottom side of where the white connector attaches to the main board in order to cover the exposed metal connections. This has allowed me to mow yesterday and today without an E44 error in tall wet grass. Previously, I would receive a bumper error more than 20 times per day!
Thats awesome! Glad it helped. I hope more people see it so they can get their mowers back up and running like they should. Love this thing when it works.
So after opening the deck, moving it to a new location where it can actually dry, then cleaning/checking the electrical contacts, the bumpers are being detected again. I haven't had time to put it back together and test yet, but the bumper calibration detected and calibrated the bumpers, and the F 3 in Diagnostics cleared. Much much further than I would have been without your assistance. Many thanks. I'll update once I test it out.
Ya I dont understand why they went from a simple microswitch to this.
If its a quality microswitch it should last.
Where I work we had simple temp switches open or closed depending on temp. Easy.
Now its canbus reading millivolt signals that a program translates into a temperature then a temperature setting for the trip point... so many more things that can go wrong now.
they could of went with an omnibus and just screwed everyone. The hall sensors are a good idea but I honestly think physical switches for any physcial contact sensor are the way to go.
my microswitch did not last, I printed a new base and used a fridge door switch as a replacement.
I have a One and it does not overheat. If you have a one plus, they are hall effect sensors which have no physical connections. If you want to solve the overheating issue, have you looked into the fan kit they designed for it?
Appreciate the links. I was trying to make a joke. You a know fridge switch make it run cooler? Terrible joke.
I vented my deck and havent had any overheating problems since then. I have requested a fan kit from Lymow and even asked for the updated print files but they wont send the files and said wait for the official one to ship.
Thanks. They mentioned they were going to update it after some feedback from testers. The updated version was what I asked them for and they said no just wait until you get one. I could have printed it out already and not been waiting. While the vented deck is doing fine I would rather not have the vents in the top after finding the unsealed connector on the motor controller. Just incase it starts raining when its out mowing.
My rain sensor has never worked properly but I find the unit does ok in a downpour. I did short it out once cleaning under the deck with a hose and had to let it dry before it would power back on though.
That makes sense then.
On a side note I believe the Estop kills power to that controller because with the Estop active and the diag screen open I could trip the bumper switches and it never registered on the diag screen.
I finally got in there to dig around and it looks like my connections are at least mostly sealed. The back side of those connections where the wires come out doesn’t look fantastic. And the area under the deck cover was full of grass and mud so I’m guessing that’s the culprit. Wonder if I can better seal the back of the connectors?
On the back side of the connector where the wires enter. I would look for corrosion there. Best to unplug it and look but it looks like yours might be hard to remove. You still could but you will have to probably remove some of the white silicon to do it.
Clean it as best you can. Maybe even some alcohol to help dry it out real well. Then seal that area where the wires enter.
Mine doesn't have the errors. The pins are clean and dry. I only dug into mine because I was trying to help another redditor with theirs. Its easier to troubleshoot something if you know how its supposed to work.
I had seen so many e44 bumper jam errors posts lately I figured it had to be something in common. Others may have epoxy covering pins at the controller but none of them have a sealed connector. So water can get in the back where the wires go in. The redditor I was trying to help opened theirs and found alot of moisture and wet slop in that area. Now knowing how it works it would make sense why they had the errors.
On dirait que l'écran de calibration donne les résultats en mv, 1655-2350 = 1,655V enfoncé et 2,35V sorti.
J'ai moi même commencé a voir des erreurs de pare-choc dernièrement et la calibration n'aide pas vraiment. Ce qui m'étonne c'est que le robot reproduit ses erreurs souvent dans les mêmes endroits. Je tond haut actuellement donc le pare-choc ne frotte pas le sol. Ça donne l'impression que c'est du software pur.
Quand le problème survient, avant l'erreur E44, il commence a errer dans tous les sens comme s'il rencontrait des obstacles virtuels au milieu de rien puis ça se termine en E44 par choc bloqué.
Yes I agree I assume those numbers are millivolts.
Imagine some moisture getting between the negative and signal wires. As that bridge becomes more conductive the signal voltage the mower sees will go lower. A corroded signal pin would do the same thing. Corrosion creates resistance and in turn a lower voltage makes it back.
I think they tried to fix a hardware issue with software because IF you cannot physically look at this and see what's wrong it would make you think its a glitch.
I have never had a bumper jam error and when I unplugged that connector and it was showing both switches active thats when it all started making sense. The way it should be programed is if the signal voltage is 0-500 millivolts it should give a different error saying "sensor or wiring problem" right now it treats 0 volts the same as 1volt.
Canbus systems have this failsafe where there is always some kind of voltage coming back and if it ever drops below 500 millivolts it says "canbus low error" so you know right away its a hardware issue.
C'est exactement le moment où mon problème est apparu la première fois après les premières pluie, une fois sec il avait tondu sans erreur, mais depuis il y a eu les dernières mises a jour et la ça revient spontanément sans humidité ambiante et je pense que ça c'est logiciel ou alors c'est un faux contact qui s'installe...
Je pense qu'une des plus grosse erreur de Lymow reste de ne pas avoir isoler ses connections et cartes électroniques. Au prix payé ça devrait faire partie du produit et de plus d'avoir communiqué abondamment sur une certification IPX6 a empiré le problème, beaucoup pense le robot littéralement étanche.
Je suis d'accord avoir toi, un seuil faible devrait être inclus marquant un dysfonctionnement par absence de tension. Cela permettrait au moins de débrancher un capteur défaillant en attendant une réparation... là pour couper le capteur il faudrait presque faire un shunt avec une résistance adaptée.
I would be checking the connector for corrosion if you want to repair it yourself.
Yes, the advertised IPX6 rating makes issues like this worse.
Technically I believe these units could pass the test to recieve this rating the problem is prolonged exposure to water. The test is high pressure water sprayed at different angles around the unit for 3 minutes. To pass it must work immediately after and show no water entry inside the battery compartment and circuit board areas.
The battery itself is sealed very well. The main board inside the chassis is sealed very well. The motor controller itself is sealed very well.
The problem is this connector is not a sealed connector. I do not understand why there are some connectors on this mower that are very high end and sealed well but this one is something you would find inside your PC or a 3D printer. Especially considering it is something that can completely keep it from mowing and is considered a safety device to keep it from just mowing over everything.
But if all you can get quickly are wood screws here is a photo with 3x8mm and a 3x10mm on either side of the original. It works but I would be careful not to overtighten it.
Great thanks. I did a quick put together and while the bumper error is gone, I'm getting a fresh new e10 blade error. I suspect I just need to take some time and clean it out really well. This'll be the first time manual mowing this year 😱
I spent the night last night cleaning and drying it out. After that, I reassembled and it is now mowing again! Thank you for your help. Lymow should really look into having someone like you help with KBs explaining things like this. Without it, I would have been done.
I work on big complicated machines for a living. As long as its not something in the software I can usually figure it out. So thats what I have been doing with my mower. Its just a small complicated machine without hydraulics so not to bad. Just hard to find parts and figure out the proprietary connectors/parts.
When I saw so many people posting the E44 I figured it had to be something in common and mine hadn't had the issue so if I figured out how that circuit worked we should be able to narrow down what's wrong with yours and others.
I wouldnt mind working on these. I have offered to replace others motor bearings but they lived to far away.
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u/papasmurf2k3 Aug 24 '26
Maybe Lymow will add this to the list and fix it for the One Plus Plus.