John Deere 9520R cranks but will not start. 

Hey Zeth, cut the connectors off the old harness and you can use those to test the injectors while they are still in the tractor. Its very convenient make shift diag tool. One of the 13.5 harnesses I had to change I did this on and i have used the connectors for diag on other 13.5s. You can plug it in and it leaves enough wire sticking up to get leads on.

Hello from nearby Lafayette! This video gives me flashbacks of F-16 fighter troubleshooting in the Air Force. Technical orders could only give you the "most likely" route to go, but you often had to improvise, and rely on wisdom and experience to find the issue. I had one instance where I'm shooting pin continuity in a harness, and everything would always meter good. Turned out, the pin that was bad would only fail when the cannon plug was actually plugged-in, and installed in it's natural position. Goofy crap like that made you pull out your hair, but once you figure it out, there's no better feeling. Great content sir, thanks!

Excellent diagnostics right there. To anyone who is not in this industry it's easy to look at something like this, and make the judgment that some technicians just throw parts until it's fixed. As a technician, it's easy to see that some other technicians just blindly follow a scan tool or diagnostic instructions, and will also throw parts until it's fixed. Truly understanding the system and using your brain, and thinking about how the system functions and making a correct diagnostic on your own- guys like that are in high demand. You my friend are one of those guys.

I hope that rig is still under warranty. Because that would cost the customer, a fortune. Thanks for the vid.

im not in the AG field at all, im in construction, and its honestly mind blowing how many new(er) pieces of equipment yall are pulling engines out of, and doing major, MAJOR work on. you dont see this with caterpillar or case equipment. sure we have had some small issues with our newer machines, but nothing like i see in these videos.

Great video showing some of the diagnostics needed on modern Farm Machinery and modern equipment in general. I salute every Tech out there that deals with stuff on a daily basis, thanx for what You do.😃

Zeth and Josh fixing it all!! Good video!!

I am surprised they didn’t have you do the electrical test from harness to ECU before pulling injector harness

Wow. A lot of sick Deere's

Ya buddy!!!! Great way to start a Friday. Just finished repairing a New Holland combine and was talking to the tech about ZK Mastertech and he loves watching your channel too. He did say though that your machines are always clean though!!?? What gives??😂

Zeth ,josh and you make a awesome team ,love your show please be safe.

You guys are awesome! That is some major engine work on big John Deere tractors! Love the show!

JD's warranty budget must be massive...

Thanks for another great video ZK. It was interesting. Wow. Lots of electrical technology to figure out in this one. You and Josh had your hands full with this one figuring out the problem. ZK and Josh you did a great job on this one with ZK doing the technology end of the problem and Josh handling a lot of the taking parts on and off end of things. The two of you display great teamwork plus sharing your thoughts on the technical end of things. I had no idea on this one but your Deere background and looking at different parts gave you both an idea of where to go figuring this one out. Nice work ZK and Josh. These new pieces of equipment are not the easiest pieces to figure out sometimes. My compliments to you both for making it run again. Yea!!!!!!! Plus you were in an open windy field making working conditions not the best. Know for sure the farmer appreciated you getting it going again and back to his field work. Happy customer I am sure. About it I guess. Nice video gentlemen and great technology fix. Proud of you both. Thanks. The Iowa Farm Boy. Steve. 😊👋👍🇺🇸

As a long time Southern California resident, Sloan Implement was ringing a distant bell in my head. But I could not figure it out. Then Assumption (the town) was mentioned. Well I grew up in Decatur, and that solved my dilemma. I must say your notion of actually trouble-shooting instead of blindly replacing parts till it starts was very very impressive. Truly an outstanding job. The farmers of Central Illinois are lucky to have guys like you working in the wind, the dust, the cold, the mud, the snow and hail, the overwhelming summer heat. (All my memory). I sincerely hope you are being paid enough to recognize your hard work and talent. There are a lot of technicians in this industry, and then there are people that get things running by first thinking with their brain about the problem. I hope that Tom and Larry are very aware of how much money in wasted time and man-hours you just saved them. And the farmer. And John Deere. And kudos to the inventory managers who make sure these parts are in stock. I'm a fan. Keep the videos coming. Heck I would put you guys in charge of Deere quality control...now that would be something. And I definitely agree with the commenters about the poor quality of much of this equipment, most of it relatively new. Major engine problems? ECU/ECM failures just piss me off as these modules should be bullet-proof. literally and figuratively. Deere should be ashamed. This poor quality is right up there with Hyundai.

Your videos are awesome. We get to see what you see and get educated on John Deere equipment. I’m really enjoying you and Josh and the other techs, I’m not sure how to spell the techs name on the engine carnage, but it’s great content

Hi Zeth/Josh. Just another great video of the work you both do in and out of house. Brilliant Looking forward to the next one. Julian U,K

Hi guys I run a diesel shop in the uk Delphi have a tool for checking those injectors YTD720. It comes with a lead and check for insulation,resistance and inductance on both coils on those units.

This was a great video with awesome outside the box thinking, and troubleshooting! It pays to understand how things work in order to fix them. Well done

Good time lapse music! These are very informative videos. Thanks Zeth!

Zeth, great content as always. Keep the action and knowledge coming. Definitely look you up at the next one. You all stay safe!

I hate when factory flow charts for diagnostics stop at a point like that as if the only possibility is the wiring harness. As a tech, you know there are other possibilities but at the same time you are following the manual from the factory. I just wish at that point they said "disconnect the injector harness and and retest." Save you from wasting time installing parts that aren't needed and help get the equipment up and running right quicker. GM diagnostics are often the same. Still, you persevered and that's what matters. Good content.

I'm a Ford tech we have had injector drivers and also coil drivers short to ground in the ecu good job we all half to think outside the box right, pinpoint tests sometimes lead you into oblivian and beyond we love our job right!

You truly are a master at this new stuff 🤘

Wiring problems are especially fun when the wiring diagrams are wrong in some way, shape or form. I used to work in the car business as a tech so I can relate.

Thanks for sharing your struggles with us Zeth. I learn something from you in every video. Keep up the great work!!!

Good video Zeth!

Cracking diagnosis impressed how you work out all the problems that you encounter great video thanks

Remember the day's of the 2140's and 4240s, 15000 hours before they needed a spanner on them.. pre emission's!!

Wow! I thought Deeres would be more well put together. Them little things cost big. This retired farmer used to rebuild skid steer carburetors on the kitchen table. I don’t know what anything is now. Stay safe. I like to eat cheap

So much knowledge goes into those tractors - cool you guys can do the work.

Another great vid! Good job,keep the deere's running!

Remember back before everyone had their own sippy cup?

If it’s a 13.5 that starts and dies it’s always the ecu. There’s a dtac solution about this. I’ve even had 6090s do this. Injector drivers are finicky in these controllers. Fuel cooled level 33s fail quite often.

Up here in southwestern Ontario all the John Deere shops are busy with the new equipment they don't have time for us guys with old equipment we have to fix it ourselves no does it tell you something

Man do I have a video for you, had a 9750sts canadian special with the 12.5L in it. Injector codes for cylinder 5 short. Did similar diagnostics as you did but in the process of diagnostic I did a wiggle test while cranking it over, well I'd be dammed I bumped the ECU and it spuddered to life for a second. I ended up switched the ECU and that fixed it.

i wish you would have shown us more like replacing the ecu and taking parts off the top of the engine and maybe a bit of you programing the ecu people enjoy videos longer then 21 minutes. that said you do make great videos keep up the good work.

Stunning video Zeth............ECU cooled by fuel...........god I am getting old......

Yeah, pretty much! Thanks for the video

I try to read through the diagnostic chart and see if there some easier things to test even if it not in the order they give you. Sometimes they have you taking the engine apart and then later check a fuse.

Never ending motor work with the green stuff

yooooo i work at the assumption store that freaking awsome! keep it up man im L&G personally buut nicee

As soon as you said driver code at the beginning I thought to myself hopefully he brought an ecu 🤣

my r4045 sprayer hade that problem it said number 5 put on an new acu never missed a beat

I had the book blatantly lie to me (as informed by IT for the company and his correspondence with Deere) on an exhaust throttle actuator for an IT4 4045 that would not regen cause it was working sometimes then kick out, customer already installed new $1k-ish actuator, I did the relearn, it made it 50 feet out the door, threw the code and derated, harness tested fine before the relearn. Tore the engine harness apart because the same diagnostic procedure said X pin to Y pin is supposed to be 100k ohm, I had 3 ohm second time I checked. Finally said F-it and donated an ecu from another tractor I had injectors out of for the 3rd time and its first EGR Cooler failure, machine ran like a top, so in the end I spent hours chasing a harness issue that stemmed from the driver circuit of the ECU because the book gave me the wrong resistance. Kinda glad no one jumped the gun in chain of command and order the $2200 engine harness that is still backordered as of 3 months now. Gotta love it lol.

Great work as always!!

I'm so glad I don't have all that crap on my tractor. I don't know how they can deal with days down.

Great diagnostics! Do you put the old injector harness back in since that wasn’t the problem?

These videos are great, what was a best guess for the repair cost on that ecu 9520. You probably can't say, some green models are great and others seem like lemons.

Wow thats lucky it was ecu! Great ez location to switch too! I do like those ecu connections JD makes!

TOO MUCH TECHNOLOGY! 😖 the more complicated they make em the more things can go wrong. Love ur videos very educational. Put all that schooling and knowledge to work. Look forward to the next videos.

JDG10466 or any flex probe kit….make getting into those injector connectors a lot easier. And handy for a ton of other stuff.

I hope this is warranty work. A failed ECU should be covered for many years by Deere.

Great work team..... Thanks for sharing

Wow now I know why the Welkers still run 40 year old Big Buds. Big Cam Cummins without all the electronics

Is an insulation tester, otherwise known as a megger, in your trouble shooting tool bag? These can be bought to be 250V dc, 500V dc. This type insulation diagnostic tester stresses the insulation, to help assist in determining if a wire is shorting to ground or to another wire. This type tester is for stressing wires that are disconnected from any electronics. Coils and robust electrical devices can be tested, not electronics. Just an idea.

JD diesels seem just like cars. ECU + harness(s) +device circuit code. What ya gonna do? check device? Nope cant get in there. Ok put in another device. Same trouble. (Saved trip to shop). Okay . Pull ECU plu and check back from device. Poifect. Get a new ECU and but it up. Sounds just like South Main Auto ch and Pine Hollow AD. That farmer should be glad he has Zeth and Josh. Zeth knowledge is amazing ...from sieves in a combine to leaky axles to ECUs. leared a new term "Green Iron."

As always. Very interesting

Awesome video.. Thank you.

I’ve had good luck just taking the rocker assembly loose and sliding the rocker arms over to gain access to the injector to pull and replace it. Without taking rocker box off or turbos.

Not a good day for 13.5 liters. 😂

you also could have a rub thought or pinched wire along that harness and now have moved those wires thus eliminating the short to ground

It is amazing how they can build those microscopic computer chips to withstand the heating and cooling as well as they do. Most times, it is probably some tiny capacitor or resistor inside there that fails, & you end up throwing away millions of good ones. Imagine what is inside a new smart phone. Who, 50 years ago, thought you could ever put a powerful computer in your shirt pocket. Drive safely.

I’ve had injector drivers fail on a few times on 9RTs also there’s a Dtac case on failed ECU for spill voltage. Also I miss the old standalone service advisor 😢

Back when i was working at a CLAAS dealership, during my vacation we had a customer come in with an old style Axion 810 tractor, it has a 6.8l JDPS engine. He would get a DTC for injector control circuit short to ground sporadically during work. Colleagues of me replaced the Injector harness in the head, no success Replaced all 6 Injectors, no success Replaced the ECU, no success. Keep in mind the customer would always get the tractor from the shop and try it out because the issue would appear sporadically. Over the weekend when he tested with the new ECU, still no success, came in on monday when i was back. Foreman ordered me to try and find out whats going on. Checked the DTC, thought for a sec, welp lets do a visuel check first. Checked the engine harness, found something that felt off by hand, had an apprentice run it while i fiddled with the loom, boop engine off, DTC active. Turns out the harness had rubbed over a metal edge because it was layed out wrongly after the head gasket had been changed years ago. Customer was happy about the easy fix in the end, but boy the time and money it took, he wasn't happy about that.

Wow excelente diagnóstico thanks

Here you got a 5☆☆☆☆+ example that even the best diagnostic programmes & sensors often cant give the clear problem, agree or not?! From Peter Eriksson Sweden Europe 😊😊😅😊!

What happened to make the engine in the shop blow a head gasket?? Did it overheat before an egr cooler replacement?? How many hours are on the engine? How many hours can one expect to get on these engines before a head /head gasket failure with properly done preventative maintenance?

Following fault diagnosis charts can sometimes lead you down the wrong path. So have to think outside the box. Like you both did. Nice fault finding and repair. Just a thought if you keep the old harness you could use some of it to test the injector. Looks like you have got a nice project coming up 👍👍👍

I wonder why Deere doesn’t have an engine harness?

Great work guys what a team thanks for sharing 🦘

you do seem to get a lot of electrical issues with fairly new looking kit

Thats a good intro...seeing something getting worked on...

From Morrocco i like all your vidéos good job

They all have issues. That’s wild

Very nice your videos , MASTER TECH.

Very nice your videos , MASTER TECH.

Very nice your videos , MASTER TECH.

Sure glad I'm not working as a mechanic anymore with all those computors, started on JD Ag in 74 then went to JD contrustion in 75 to 80 then went farming for 14 yrs then worked as a mechanic for the county and farmed for 20 yrs, decided I had enough of computors in 2015 and switched to driving truck for the last 5 years

ECUs should be built with opto isolation to a driver module so output failures do not affect the ECU!

Very nice your videos , MASTER TECH.

Yup yup yup(as an Ex-ASE tech specializing in diagnostics of electronics) the diag tree isnt always correct

Very nice your videos , MASTER TECH.

Keep the Video coming!

Good job buddies 🔧🔧✌️

dtac! hahah nice work guys

Great content subbed

Another day at the races !

A failure in any ECU can be difficult to diagnose!! Thanks!

If the old harness is junk .... cut an injector connection off .. tada... tester lead extension

who pays for the not needed wiring harness - customer / sloans / deere ??

Everybody loves John Deere DTAC. If you know what DTAC is you understand.

More JD harnesses....was at least 2 blades down out of 8 every month at county shop Junk

Be careful with leaving the gauges on the bottles

Do you get opportunities to submit new ideas for diagnostics based on what you find in the field? Seems like a logical place to start would be different that what the diagnostics say. Thanks for another great video. Please stay safe, and God bless.

Any suggestions or advice for someone trying to leave the automotive world for the agri world?

I always do my harness check from the eecu plug frist .

Checking for short to ground at the injector connector without disconnecting the harness where it enters rocker box is not a good test. Unplug the harness at the rocker box and test for short to ground at injector 5. The first thing I would have done is unplug ecu and test the wire to injector 5 in the connector and see if it’s grounded. If not it’s the ecu. Always break circuit into smaller pieces before testing with meter for shorts to ground. I would have used a test light hooked to batt power but that’s me I hate using ohms to check wiring. I always load test a circuit.

Just a question. If it is a short in the engine harness why cant you just replace the wire or repair the area thats causing the short? Is it a standard thing now to just replace the whole harness?

Sounds like the engines in the 9510 and 9520R tractors have LOTS of mechanical failures. That is the John Deere engine correct?