L3901 Operator Presence Control Troubles......

[Copyrite1972]

I became a new Kubota owner in July, bought a 2018 L3901 HST from a friend with 98.5 hrs on it. Thought that spending a lot on a basically new tractor would ensure me years of trouble free tractor joy. The 3901 was pristine, always kept in a barn under a blanket ( Honest!)

After 6 months of enjoying it, at 158hrs I have had my first mechanical challenge........

I was out moving snow (The main reason I bought the tractor, we get a lot!) it just up and quit! Started it back up, tried to go forward, and it died again! Started it back up, checked the throttle, idled up fine, checked the hydraulics (Bucket, and 3 point) worked fine, damn thing just died when I tried to move it.

Dealer #1 "It HAS to be the seat switch" I drove 2hrs 1 way, spent $70.00, didn't work. Found my meter, old switch works fine. New switch is adjusted good.

Dealer #2 "There are only 3 switches in the OPC on the 3901, it has to be one of them, or bad wire" Tested all 3 switches, they all seem well. no dice.

In addition, I have pulled, and checked all fuses. NOPE!

I can move the tractor at a snails pace, but too much petal forward, or back, and it tries to die, and I get the OPC code on the dash.

What am I missing???? Snows piling up, and the wife is looking at the 20K orange rock in the shop with a "What the hell" look on her face!!!!

Hope I included everything, Thanks in advance,
Copyrite1972

 

[85Hokie]

Despite checking them out and continuity testing - I would bypass all three safety switches with a zip tie.
Try to move ---- if same results, it has to be a wire that is chaffed or broken.
Have you traced the path of each wire?

 

[whitetiger]

I became a new Kubota owner in July, bought a 2018 L3901 HST from a friend with 98.5 hrs on it. Thought that spending a lot on a basically new tractor would ensure me years of trouble free tractor joy. The 3901 was pristine, always kept in a barn under a blanket ( Honest!)

After 6 months of enjoying it, at 158hrs I have had my first mechanical challenge........

I was out moving snow (The main reason I bought the tractor, we get a lot!) it just up and quit! Started it back up, tried to go forward, and it died again! Started it back up, checked the throttle, idled up fine, checked the hydraulics (Bucket, and 3 point) worked fine, damn thing just died when I tried to move it.

Dealer #1 "It HAS to be the seat switch" I drove 2hrs 1 way, spent $70.00, didn't work. Found my meter, old switch works fine. New switch is adjusted good.

Dealer #2 "There are only 3 switches in the OPC on the 3901, it has to be one of them, or bad wire" Tested all 3 switches, they all seem well. no dice.

In addition, I have pulled, and checked all fuses. NOPE!

I can move the tractor at a snails pace, but too much petal forward, or back, and it tries to die, and I get the OPC code on the dash.

What am I missing???? Snows piling up, and the wife is looking at the 20K orange rock in the shop with a "What the hell" look on her face!!!!

Hope I included everything, Thanks in advance,
Copyrite1972

You just need to adjust the Hydro pedal safety switch in 1 to 1 1/2 turns. I adjust at least a dozen or more a year.

 

[sheepfarmer]

9 times out of 10 it is the seat switch, and whether it is being activated by the way the operator sits on the actual seat. I have 2 different tractors of same vintage, and both have had the tendency to have finicky seat switches in the cold. The sensors are not the same in both, and neither can be zip tied down. I don’t know where the sensor is in the 3901. Or how it is activated. When you bought a replacement, what was it, and where did it go? Mine can be activated better with strategically placed cardboard or a piece of styrofoam since it is a broad pad Velcro‘d to the seat.

The tractor will also die if the pto is turned on if the seat switch is not showing an operator. What happens if you try that?

edit: try whitetiger’s suggestion first, just saw it.

 

[North Idaho Wolfman]

Yep HST Pedal switch was my suggestion too!

 

[sheepfarmer]

The seat switch issue when the seat is cold is aggravating. It is worse when wearing a bulky down coat, but it will stop cutting out after being on the tractor for about 5 minutes. Might take me 5 tries to get the 2650 out of the barn to snowblow, and once it is going it stays going for rest of time. We’ll see if my current piece of styrofoam will do it better this winter. Have not tried any adjustments to hydro pedal.

 

[Copyrite1972]

Despite checking them out and continuity testing - I would bypass all three safety switches with a zip tie.
Try to move ---- if same results, it has to be a wire that is chaffed or broken.
Have you traced the path of each wire?

Thanks!

How do I bypass them with a zip tie? And the tractor is in the shop tonight, so I can trace wires tomorrow.

 

[Copyrite1972]

PETAL SWITCH, PETAL SWITCH, PETAL SWITCH!!! Just went to the shop after reading everyone's input (Thanks to all BTW!!) bypassed the petal switch with a small piece of wire, and I'm back in the snow moving business!!!!

I'm going to return the seat switch, and use the money to buy a new petal switch.

Thanks again!