L4760 ECU issues

dimka1980

New member

Equipment
Kubota L4760
May 14, 2022
3
0
1
Eastern Europe
Hi everyone,

Hope you can help me. I have a L4760 tractor, last year in the fall it was parked, and then next year it won't start. starter working, but won't start. P0605, I think pop up. I am not in the US and can't take tractor to dealer. So, I tried to fix the issue my self. One of the guys who looked on it, said that the ECU is an issue. New ECU is expensive and most importanly not easy to get because of shipping. So I got similar ECU, my guy was able to re-record original software on it, now when intall, P0605 is gone, but "error 20" is what I get. Do you guys think that this is because of the ECU being not original, or some other issue? Am I left with the only option to check is to buy new ECU from dealer for approx $3,000? Thanks in advance
 

JerryMT

Active member

Equipment
Kubota M4500, NH TD95D,Ford 4610
Jun 17, 2017
396
75
28
The Palouse - North Idaho
Hi everyone,

Hope you can help me. I have a L4760 tractor, last year in the fall it was parked, and then next year it won't start. starter working, but won't start. P0605, I think pop up. I am not in the US and can't take tractor to dealer. So, I tried to fix the issue my self. One of the guys who looked on it, said that the ECU is an issue. New ECU is expensive and most importanly not easy to get because of shipping. So I got similar ECU, my guy was able to re-record original software on it, now when intall, P0605 is gone, but "error 20" is what I get. Do you guys think that this is because of the ECU being not original, or some other issue? Am I left with the only option to check is to buy new ECU from dealer for approx $3,000? Thanks in advance
Do you have a work shop manual and/or an owner's manual for your tractor? It may have error code definitions in it. Someone who knows may get on this forum and help you. Or contact a dealer somewhere and ask them.
I wouldn't throw parts at it, especially an expensive ECU, unless you understand the error code.
 
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Dieseldonato

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B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
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Pa
Typically modern ecu are very robust. I think I replaced a total of 5 in all the years I did road work. At least 3 were customer induced issues. Unfortunately like mentioned above you need a workshop manual. I would think more specifically for the engine, but the wiring schematic will be needed either way. A crank no start could be any number of things on a common rail engine and not being there doesn't help any either.
During a search of your P code I did come across something that suggested poor power and or grounds going to the ecm. Unfortunately with out the pin out of the ecm, you won't know what to check. Normally there are several powers and grounds that feed an ecm.
 

sheepfarmer

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Lifetime Member

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L3560, B2650, Gator, Ingersoll mower
Nov 14, 2014
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Error 20 is “communication error between ECU and Intellipanel”.
I am inclined to guess that starting by replacing your old ECU with a “similar one” was not a good idea. The ECU has to have certain parameters from the injectors etc programmed into it to work. Given the fact that it was working last year and P0605 is a communication issue I would guess that there is/was a wiring issue. Or a ground issue, or a battery issue. Any chance you can put old ECU back and trouble shoot all the connections if you didn’t do that already?
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
3,686
805
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Mid, South, USA
P0605 can be triggered by a low battery. That's the most common cause from what I've seen.

now you have a potentially bigger issue

those ecu's are not easily programmed, only way i know is use of kubota dealer specific software, which requires a license and once all that, a set of codes have to be entered and the actual software downloaded, then installed into the ecu-and the actual software isn't available just everywhere for obvious reasons

there is more than one software program for L4760 too-they ain't all the same

the ecu case itself (the metal box that you plug the harness into) is externally similar to some Polaris and Kawasaki ECU's but there's hundreds of internal differences. U have a very sensitive set of sensors and actuators that may have been damaged if an ecu from a different machine is used.
 

whitetiger

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Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
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Kansas City, KS
L-Series and MX-Series - Diagnostic procedures for P0606 and P0605

Issue:
The common rail diagnosis manual does not provide a clear diagnostic procedure for these codes. P0606 and P0605 indicate a power or communication issue with the ECU. When these codes occur, the tractor may crank over but not start, and Diagmaster may not connect to the machine.

Solution:
1.
Clear the codes from the Intellipanel (refer to Mode b in the WSM). If the codes return, proceed to step 2.
2. inspect the engine ECU connector for any moisture, corrosion, or other damage to the wiring or pins. Check that all pins in the engine ECU connector are tight and in place. Check for bent or backed-out pins, or broken-off wires where they go into the connector. Pay close attention to pin 50 on the engine ECU connector (red wire) make sure it is secure and tight in the connector and no corrosion is present. If an inspection reveals no abnormalities, proceed to step 3.

3. Plug the engine ECU connector back in, and with the key on, check for battery voltage on pins 4, 6, and 71 of the engine ECU connector. Should be approximately battery voltage.


4. With the engine ECU connector plugged in, check voltage at pin 50. With the key on, the voltage should be less than 1 V. With the key off, the voltage should be approximately battery voltage.

5. Remove the engine ECU connector and check continuity to frame ground from pins 1 and 2 of the ECU connector. Resistance should be less than 1 ohm.

6. If all of the above tests are within spec, try swapping an engine ECU from a known good machine. If this resolves the issue, replace the engine ECU.
 
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dimka1980

New member

Equipment
Kubota L4760
May 14, 2022
3
0
1
Eastern Europe
Hello everyone, and thanks for the help. What has happened, is that one of my workers (not working for me anymore) most likely did something with the starting machine, I think it might fried the ECU. I came over that day, tractor was parked, and I did not started to double check, so we parked it over winter, and when we try to start it in the spring, P0605 came up. I know I did something that most likely introduced more complicated issues, but I tried to open the ECU to see is there any damage (bad idea). So I damaged the ECU when trying to open. I have a mechanic locally who owns the software to tell me that ECU is not responding, then he got the ECU back to responding, but when we plug it in still the same issue. So he suggested to replace ECU. I purchased one that is exactly the same from the outside, then we deleted the software on it and record what was on the old ECU, and now we are not getting P0605 error, but error 20. I am inclined to think that it might be because the new ECU might not be the one that is working on that tractor. First 2 images is old original ECU the other ones is the new one. And so, now I think that my only option is to get the ECU from the dealer and that's very pricy for me.
 

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Dieseldonato

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B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
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43
Pa
Honestly you should have gotten the dealer out in the first place. Would have saved you a lot trouble. If the ecu can't communicate with itsself your buddy likely didn't actually copy everything off it to the new ecu.
Not that I'm a fan of paying for service calls, but I would suck it up and get the dealer out. Explain the issue(s), what you did/tried to do and let them test every thing. It's highly possible you screwed up your original ecu. Throwing expensive parts at it won't help anything.
 

sheepfarmer

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Nov 14, 2014
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Honestly you should have gotten the dealer out in the first place. Would have saved you a lot trouble. If the ecu can't communicate with itsself your buddy likely didn't actually copy everything off it to the new ecu.
Not that I'm a fan of paying for service calls, but I would suck it up and get the dealer out. Explain the issue(s), what you did/tried to do and let them test every thing. It's highly possible you screwed up your original ecu. Throwing expensive parts at it won't help anything.
If you check the op original post, he is not where he can get to a dealer.
 

Dieseldonato

Active member

Equipment
B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
300
150
43
Pa
He said he can't take it to a dealer, not a dealer couldnt come out.