44-Part 2: Massimo T-Boss side-by-side troubleshooting and repairs

Replaced more EFI parts on my Massimo T-Boss 550 side-by-side, but still not fixed. Watch as I add new parts and further troubleshoot. Plus, more helpful tips and resources in this video to help save you time and some of the frustration I've been through.
For more videos about this Massimo, see my playlist "UTV/side-x-side" ( • UTV/side-x-side )
For more details about this (including operator and technical manuals) and other videos shown on this channel, and links to parts, visit twc-projects.net/resources and twc-projects.net/amazon-store
Fault Code Troubleshooting "How To"
www.utvboard.com/topic/6579-f...
P0122 Code: Throttle Position Sensor/Switch A Circuit Low Input
www.carparts.com/blog/p0122-c...

[@texasgunfan]

I’ve been considering buying a Massimo T Boss 550F or 750 and came across your videos about your repair journey. Thank you for sharing so much information about your troubleshooting and how to read the codes. I’m glad you were able to finally get it figured out and back on the trail. I’ve enjoyed your videos so much that you made a subscriber out of me. Keep up the good work and God bless.

[@twc-projects]

Thanks for the positive feedback and support. If you haven't already, be sure to see the resources page on my website for more details and helpful diagrams on the TBoss. I just recently added more details on codes and wiring. twc-projects.net

[@timsigmond8984]

Hope that's the problem, glad you mentioned how to read codes, please keep us posted. Have a Coleman 550 outfitter , so your grief may be our blessings when it's our turn, my neighbor has a Polaris and its had problems as well, keep us posted. Thanks.

[@twc-projects]

Yes. I felt kind of dumb not realizing this thing would even have codes. Wished I has started there first. I'll do a video on how to read those codes, based on the website I referenced in the Description, as soon as I get the new part. Of course the part I need, of which I ordered mid Dec, is stuck in Customs; coming from China. Was supposed to be here Jan 14, but is now saying Feb 1, last I checked. That has put a real damper on the whole awesome experience leading up to this failure. Still worth it though. Thanks for watching and stay tuned. Hopefully you'll see it running again soon.

[@cpenland]

I’ve been in this research process on these UTVs - and you’re just validating my train of thought that the Honda Pioneer is what I’ll stick with when I buy one. I realize these Chinese brands are significantly more feature laden and cheaper, but I need to stuff to work when I need it to work and not spend so much time wrenching on something.

[@twc-projects]

I totally get it. This is the only issue I've had, and the big delay with getting it running again is largely on me; trying to do it on my own and save money. The manufacturer said they replace the entire throttle body when they have issues like this, but I stubbornly refuse to spend 100s of $$ and throw away perfectly good parts when the only thing broken was a cheap $19 part. I was willing to wait 4wks for it to come from China, but the whole supply chain backup has exacerbated the situation, thus I still don't have it yet. So I've stayed busy with plenty other projects while I try to wait patiently. I just do this stuff for fun, and I totally get that for many of you it's part of you earning a living, and going cheap is not an option. In doing my research I also heard so many people complain about Honda, Polaris, John Deere, etc. about getting parts, etc. For some the solution was to have two UTVs, for "when" one breaks down, and others to have spared parts on hand ahead of time for commonly failing parts, typically fuel or electrical. So keep us posted on what you end up doing and how it works out. Thanks for your comments and for watching.

[@timsigmond8984]

Good luck with and keep us posted.

[@twc-projects]

Will do. Thanks for the support and for watching.

[@gregorypiwcio7883]

Did you try the ECU reset As you changed out parts you will need to reset ECU pedal to the floor for 3 to 5 seconds keep gas pedal down turn engine off hold the pedal for another five seconds release wait 30 seconds and start back up see what you get

[@twc-projects]

Thanks for noting that. Yes I did, but need to capture that in next video, along with showing how to read the codes from the display cluster. I recorded a lot more, but edited out because video already over 20min. Thanks for your tip, as there was an excellent chance I didn't know about resetting the ECU, and should definitely capture it on my channel to show others. Keep the great support coming. I really appreciate it and appreciate your watching. Have a great day.

[@mddoit]

Thank you

[@timroberts3139]

Raymond James had the same kind of engine fault on His Coleman brand. The short oil dip stick was causing the engine fault. He bought an extended dip stick modification and solved his problem. His video is UTV Hysun Coleman Outfitter 700cc upgrades 4x4; 6minute mark he details the problem and fix.

[@twc-projects]

Interesting. Thanks! I'll have to check that out. I'm expecting the part to arrive soon that the fault code indicated. Hopefully this is it. But if not, I'll try your suggestion too. Thanks again. And thanks for watching.

[@landumc]

Enjoyed your video! Might I ask where you bought your rear view mirror for the t-boss? I’ve looked on Amazon and found ones that look similar to yours but they say it’s for Polaris only. Thanks

[@twc-projects]

amzn.to/3TemL3p It says for Polaris, but I made it work by drilling a couple small holes. It's been rock solid. Love it. Anytime you see something on my channel, you can go to my website to learn more and find links to related resources ( twc-projects.net/resources ). Thanks for watching.

[@joeashley7477]

Great video sir. I have a question. Did you ever come across the cylinder compression specs for this thing? I cannot find anything definitive on the 550.

[@twc-projects]

I have not. But have found a few other gems you might find useful. See my website resources page ( twc-projects.net/resources ) for Massimo ECU codes and more. If you find what you're looking for, and want me to share it with others on my site, send me a link. You can hit me up directly ( twc-projects.net/contact ).

[@JustMe-cg4vp]

My question isn’t related to the subject in this video, but I see you have a lot of experience with that machine. I just purchased a TBoss 550 from tractor supply and I have only driven it maybe 20 minutes. My question and my problem is that when I start downhill, the machine does not have any pressure to slow the descent. It’s as if it kicks into neutral. Is that normal for a model with the CVT transmission? I hope not because we have a lot of hills on the property. Thank you for your time.

[@twc-projects]

Yes. This is normal for CVT. The clutch engages when the motor spins up enough to create a centrifugal force, thus causing inward pressure onto the drive belt. So, if your foot is off the gas pedal, the clutch may not be closed enough to make contact with the drive belt that connects it to the engine. This is the same as a snowmobile, if you've had any experience with those. Basically, it takes a while to get used to it and then it doesn't seem so strange anymore. It definitely doesn't feel like your typical car transmission. So keeping that in mind, when I'm descending larger hills and want the engine to assist me, I put it in low gear, and keep my foot on the gas just enough to keep the clutch engaged. Again, takes some getting used to. For day to day use though, I rely on the brakes. They work fine. Give it a few weeks, and you'll get more comfortable with it. Hope that helps. Thanks for watching and happy riding. Enjoy your new UTV .

[@johnvanwoudenberg446]

I have my friend 750 fuel injected here at my house nice looking machine but when you give it gas it hops two three times then it goes maybe somebody out there has got an idea what that could be belt driven it looks like

[@masshultzy6449]

I know this vid was a while back, but I was trying to decide between a Massimo or an Axis...What would your thoughts on that be?

[@twc-projects]

I don't have any experience with Axis, but if you haven't seen my lasted update on the Massimo, you may want to check-it-out ( kzbin.info/www/bejne/fGHclmh8greZqrs ). Hope that helps with your decision. Thanks for your question and for watching.

[@jakeschisler7525]

I see where that company doesn't make that model anymore. The new one has a big screen in the center. I've been looking at different utvs and my problem is I'm pretty tall and it's my legs that are so long and feet problem is my biggest issue

[@twc-projects]

I'm 6ft. I sat in my TBoss and used a tape measure. It sits up high, so you don't feel like your knees are up in the air or anywhere near the dash/console. I measured 6.5" from my knees to the dash and 7" from top of my head to the roof. Not sure how that will compare for you, but hope that helps give a little more perspective.

[@tmoney5092]

I have one of these. Where do you get your parts from? I want to get the throttle control sensor and have a hard time finding it on Amazon

[@twc-projects]

Check out my website resources page ( twc-projects.net/resources ) for lots more details, access to manuals, etc. You'll also find links to nearly everything I show on my channel. Hope this helps. And I have a playlist with lots of TBoss videos. Thanks for watching.

[@zmaila]

Our steering wheel won’t stay down when put in the down position. Just goes right back up. Does anyone know how to fix this.

[@twc-projects]

I haven't had this issue yet, but it sounds like the position locking mechanism might have warn out or detective. If it's under a 1yr old, Massimo might just send you a replacement part. You'll probably want to call the tech support team regardless for help troubleshooting. Sorry I couldn't really help, but thanks for your comment. Maybe someone else will see this and have a solution for you. And thanks for watching my channel.

[@lawrencewashington1810]

How do you slow down or speed up the Tboss 550

[@twc-projects]

Like most all UTVs, this drives like an automatic transmission car. It has a gas pedal and brake pedal. Very easy for anyone to drive.

[@MegaGoogoohead]

Throttle position sensor is bad your replacing good parts ! Trust me you were close to it the sensor on that model is close to the sensor you just changed but dont buy any more parts its the throttle control sensor its about 20 bucks on amazon will probably have to come from china unless you find a dealer close with one !

[@twc-projects]

Thanks Tony. You're absolutely right. That is exactly what I figured in a later video. Right after this video I ordered TPS and it took a while, because as you called it, needed to come from China. I'll have to remember to as you for help next time. You da man! Thanks so much for sharing your knowledge about these machines with me and my viewers. And thanks for watching.

[@lanceenochs]

Any luck getting it fixed?

[@twc-projects]

Just got the part I've been waiting for. Plan to install it today and show how to read the error codes, as well as reset ECU. Hopefully that will do it and you'll see the Massimo back in action in next week's video; fingers crossed. Thanks for asking and for watching; and hope you've subscribed. Take care, keep watching, and be creative..

[@heathenprojects2639]

This is a very expensive lawn orderment I've looked at buying one of this but as much problem as people have I just think I'll save the headache go with something 5 grand or so more

[@twc-projects]

This has been the most useful piece of equipment I've ever owned. Didn't truly realize how much I rely on it until it broke down. I probably should have had a pro fix it and it would done by now. But where's the fun in that. Didn't know I could get diagnostics data from ECU until after I'd tried process of elimination, only to replace all the more expensive parts to find it was one of the cheapest that actually failed. Learned a lot though in the process. Thanks for watching.

[@jeannec9112]

It will not run properly and will throw codes if you don't buckle your seatbelt

[@twc-projects]

Thanks Jeanne. I've since fixed in a later video (kzbin.info/www/bejne/eHi5iWpjaamkia8 ) and there are links in the description of this video to other good troubleshooting resources, including list of codes. Thanks for your comments and for watching.

[@davidberkley839]

Massimo became trash Wish never bought anything from them !! Won't help with nothing !!

[@twc-projects]

Sorry to hear you're experience has been so bad. Seems to be a mixed bag of feedback I've heard from folks. Different models seem to have different issues, but I have heard one thing pretty constantly--bad tech support stories. I had a good story, followed by bad. So that's definitely something to consider until Massimo figures out it's impacting their sales and gets their tech support act together. Thanks for watching.