many of the codes are set both in the panel AND in the ECU, as said previously.
To clear them from panel:
get into the seat engine OFF get comfortable.
hold down both of the buttons on the left side of the dash (some tractors will have them on the right side)--one is the regen inhibit button the other is the park regen button. Hold them down and keep holding them for a few seconds.
while holding both buttons down turn the key on.
In the display where the hourmeter normally shows hours (or your code), you should see a letter "A". If you do, let go of the buttons.
If you don't see letter "A", start over from the beginning by turning the key off.
Now that you see the "A" in the panel, reach down and mash the Parked regen button ONCE (one on the right, on the L3301/L3901/L4701)-others may be different locations. You'll hear a beep and the letter in the panel should change to a "B". If you don't see a B, or if you went too far to "C", keep mashing the parked regen button one at a time til you get to "B" and STOP. You need to be on B, not A, C, or D.
Once you are on B, HOLD DOWN the parked regen button until you get a beep then release. In the panel is should say "PUSH".
Once you see "PUSH", hold down the parked regen button again until you get a beep again. I forget what it says after that, but at that point you just cleared the code from the panel and you simply turn the key off, wait about 30 seconds, and turn it back on to verify that the code disappeared.
IF your code didn't disappear or it did and reappeared, you have a hard code or you didn't do the procedure correctly. As said some codes are hard codes meaning you won't be able to clear them. The two most common codes I saw were P0606 (low battery voltage) and P0336 (crank sensor abnormality). Please note that while automotive industry uses the same codes, the terminology is completely different, Kubota's is easier (for me) to understand. Hard code means that you can't clear it, there's some other problem and the only place that can clear it is a dealer who has access to the hardware that can properly diagnose it.
Ok so if you successfully got through using B mode to clear the panel lets go into diagnosis of the safety switches. You guys that do tech work will absolutely love this, if you haven't' seen it already. I had two techs working under me, neither could ever figure this out and it is so simple. Note that "A mode" doesn't clear any codes, it's just various monitors to my knowledge but it has a hidden function that I am not sure had an intended usage, at least for what I used it for.
Same procedure....key off, mash both buttons for a few seconds, THEN turn the key on. You will be in A mode. Mash the parked regen button and hold it down. It should beep and come up with a 1, a colon then a number or alphanumeric code. Once you are into that, let off of the parked regen button. I think it's 1 through 9. #5,6,7 are EGT's that the ECU sees at the various locations. Note that with a load on the engine at just the right RPM, your EGT can get really hot so dont stand in front of the exhaust trying to sniff how how it really is. RPM shows up one another one. Throttle position on another. IIRC #9 is a software or memory code. Anyway, at this point to check your switches all you need to do is be in one of the many sections, 1-9, I usually just use 1 because it's the first one. Each time you activate a safety switch you will hear a beep. Get up off the seat, beep. Back on the seat, beep. PTO turned on beep. HST forward, beep, reverse beep. Park brake on, beep. neutral lever in & out of gear, beep. For instance if your tractor won't start, just activate the switches by moving the levers and pedals until you find the one that doesn't beep, you found your problem. Doing it this way saves a TON of time. That doesn't mean the switch is bad, it could be a wire ripped off or possibly a wiring problem at the ecu, who knows. OFtentimes I'd go out to a field repair to a tractor that was exhibing a no-start condition after being used without problems. I'd immediately go in to A mode, diag the switches. Often I'd find that the pto was bumped without the operator knowing, A mode beep test would show it immediately. Also works with the HST pedal switch adjustment, and diagnosis of the sensitivity of the pedal switch. Real common with the earlier MX5200/MX5800 HST's
There is also a C and D mode on some models, WSM outlines them, has to do with tire sizes and a few other things on certain models. I recommend not messing with C and D as you can mess some stuff up if u ain't careful. A and B are the only two you need to know. If you get to C or D, just shut the key off and start over.
Note this only applies to tractors that have common rail injection, from 2014 and newer, and may have changed for the 2021 models. I only speak for the L3301, L3901, L4701, MX5200, MX5800, MX6000 at this point and have not verified it's workings on the bigger M series as well as the grand L-60 series. Probably a youtube video for it, and for the ones I haven't tried with.
yall might want to sticky this or at least bookmark it. I ain't on here all that often anymore so it'd be wise to keep it handy. And if there are any corrections needed, feel free to either correct them for me or ask me to and I'll edit. My apologies for any spelling errors. I type about 85 wpm and I make errors. Thank goodness for the backspace but I don't catch them all.