Hello everyone, I'm working on a JD 450J for a good friend of mine. The issue it's having is it will lose communication between the Ecu and the Tcu and throttle down. You can sometimes turn the key off and on and it will let you throttle it back up but sometimes it won't function again until the next day. I've taken the Ecu to a dealer for testing and it tested good to what they were capable of testing it for out of the unit. When the 450 won't throttle up the display on the TCU is blank and you have no access to the menu or diagnostics. I've swapped the TCU from a 650H into the 450 and that TCU would power up and show display properly but the 450 Tcu in the 650 still would not power up and show the display. I put the 450 Tcu back in the machine and the next day it is working again. I know it's not going to last and I'd like to get the Tcu sent to someone reputable who can test it and repair if needed. I've taken the Tcu apart and cleaned it, it was full of sand/dirt. I'm pretty sure it's the culprit but I appreciate any advice I am given. When it immobilizes, I get active code 609.9 on the sdm. Thank you for any help you can offer
Welcome to HEF Jeff ! First thing, post a complete machine serial number whenever you start a thread. Code 609.09 is a loss of communication FROM the TCU. If the connections to the TCU are sound, clean and tight, and voltage and grounds are not getting interrupted to the TCU, the CAN communication wires also sound, and their connections clean and tight, then you will most likely need a TCU. If that machine is an open ROPS, those TCU's had a bad habit of allowing water entry. Once that happens, game over. Maybe, if you are lucky, the connections for the power, ground or CAN wiring inside the TCU might have cracked solder joints that you can see and repair??
Mg2361 has you on the right path here with the suggestions especially if open ROPS. How many hours on your machine. I have had a couple of J’S that had a problem with Can Termination Resistor with moisture or bad resistor A good resistor usually measures around 119 OHM’S.
Thank you for your reply my SN is T0450JX115324 and it is an open ROPS .I've checked all the connections, and they seem good with no corrosion. Hots and grounds seemed ok. I checked continuity on the green wire (CAN ?) from the ecm to tcu and it was good. As Steve Austin suggested I checked the resistors by the Ecm and Tcu. They were both like 121 ohms. The board of the TCU looks horrible, but I resoldered the pins and it made no difference. I'm attaching some pictures. The one with the red dot on the display. Could anything cause that other than a bad TCU? Voltages were fine coming into the unit. Thank again for your help
Just for a simple test disconnect a sensor, you can probably access one easily at left access door at bottom of FNR lever turn ignition on engine off and check for 5 volts power on sensor harness sometimes I have had no 5 volts or low voltage power to sensors if TCU is bad but not always the case.
Ok, I’ll try that tomorrow morning and report back. Thank you
Seeing that circuit board, you know how this will end up. $$$ Though I have never used them or know anybody who has used them, you might give ERD a call to see if they can help you. Click on the ERD for the information.
Today I went to check for voltage at the sensors and the TCU decided to work. The dozer ran for an hour, 30 minutes of that was pushing down trees. When it immobilized, I checked and it had 5 volts going to the sensor. After a few minutes I started it back up and the TCU was back online, so I drove it back to the shop. Oh yeah lol , a dealer a few hours from me has a new one for $4,300. Which is ok, if that's the problem. I'm going to give ERD a call and see what they say. Thanks again everyone
Will it let you read codes when starts working?
Went on ERD website they list a 3 year warranty on their repairs.
Yes it will let me , The TCU has no codes. I cleared them a few weeks ago and none have returned. The Sdm has no active codes or sometimes a 174.3 for the fuel temp sensor. When the TCU is offline, the Sdm will give 609.9 and 91.9 Thanks
I am sure you have checked this but is the little ground strap in good condition and connections clean. No corrosion.
Yes it is, that was actually the problem on this machine a few years ago. It was doing the same thing it is now and I cleaned it up and it lasted until now.
I checked voltage on the green wire going to the tcu plug today and it read 2-3 volts. This is for the Can correct? Is that enough voltage? Thank you
From what i remember Green is CAN low Yellow is CAN High. [I may be wrong on remerging part.] CAN low green 2 to 3 volts i thank is correct CAN high yellow i thank was 1.9 to 3.1 but not sure but if your TCU goes blank loses power etc. you will lose CAN communications and usually machine will stop moving.
Hello again everyone. I contacted ERD and sent the TCU to them for repair. It was in fact bad and they were able to repair it. They seem very reputable and I appreciate the recommendation. I hooked it up to the machine and everything worked , it just needed calibration. Now my new problem is it's failing calibration. It's the Decel sensor giving me code 359 now. I bought a new sensor and it didn't help. I can adjust the decel pedal some and get a different code like 356. I am getting 5 volts at the sensor. Any ideas of what else to try? There are no active codes on SDM. Thank you for your help
When the controller asks for decel down are you pushing pedal to first stop and not pushing into brake position by accident.This position has more resistance?
What Steve mentioned is a common mistake. Make sure you have the pedal in the correct positions for each calibration step. If you have the pedal in the correct position for each step, then check/adjust the pedal voltages to the specs below and try calibrating again. Decel pedal voltages should be: Up position: 1.40 - 1.55 volts Low position (when resistance is felt): 3.40 - 3.60 volts Brake position (all the way down): 3.79 - 3.99 volts
Steve was right, I was pushing the dec down to far for the decl . What I ended up doing on the decL was press the pedal down slowly until it asked for decH and released it slowly until it asked for throttle H. It ended up finishing calibration after a few attempts. What’s weird is the engine wouldn’t rev up for the second step the first time and I had to try again after turning the machine off an on several times before it would rev up again. When the engine would rev up , there weren’t any codes on the SDM or the TCU. I went to diagnostics and watched the voltage change as I turned the throttle knob , so the TCU is receiving signal from the sensor. After I finished Calibration it didn’t act up again and everything seems fine. Hopefully it stays that way. I am forever grateful for all the help you guys have given me.
Thanks for posting the results on your controller issues. If you start having throttle problems or decel codes I would perform the voltage checks posted by mg2361 by back probing the decel sensor connector and recalibrate.