2012 Cat 246c RH joystick controls inoperable

Hello guys! My name is Shawn and live about 45 minutes north of Baltimore MD.

I have been surfing the page trying to help a buddy with his 2012 CAT 246c skid loader which he recently purchased. His RH joystick for boom functions does not work.

First..I am a complete novice to working on a skid loader... However; I am pretty involved with automotive performance turbo applications/customization and have a nerd hobby of soldering/repairing circuit boards, SMD/IC chips etc.
So I feel fairly comfortable with troubleshooting/process of elimination.

His skid loader is serial number JAY06980. 2012 model. CAT 246C. Uses the Hydro-electric joystick controls .

The issue is his RH joystick is NOT operating the boom lift, bucket/tilt etc.
Everything else on the vehicle seems to be in working order. The skid loader starts, runs very smoothly and drives.
All of the interlocks DO seem to be working properly. Seat pressure, door, arm bar switch. Do work.

It does however have the flashing yellow driver alert (non-audible) which I gathered is a stage 2 fault?
Unfortunately, I do NOT have access to a scan tool and the machine also does NOT have the upper-RH display to display a code/fault.

I am curious if there is a pinout that may be possible to jump.. Similar to how obd1/obd2 ECM for automotive can be done to display a sequence of flashes to communicate a code?

The RH joystick, the thumb roller DOES bog machine down in both directions and the AUX Hydraulic lines DO jump.. So that portion does seem to be working.

I gathered up what I can so far on various pages to find schematics.. But am not 100% on the Values/specs that I should be looking out for.

I haven't had a ton of time to trouble shoot just yet..

However;.
So far.. I have tested on the RH Joystick 127-CH orange 12v b+ wire IS getting its voltage (12v off /14.3v when running)
And the 203-CH23 black ground wire has continuity to the chassis.

The other two wires.. On the 4 pin connector, BROWN wire and WHITE wire (which I read is the X and Y-axis signals to the ECM. I am unsure what values I should be seeing to test those..

I plan on atleast OHM testing each of the wires for the two separate harness connectors on the RH joystick to their destination points at the ECM .. To make sure there are no breaks in the circuits.

From the looks in a schematic I found.. It appears that the two signal wires (brown and the white) go to the ECM..

And then there is an output from the ECM to the solenoids on the Hydraulic pump? (I have not tested the solenoids yet either..and wasn't sure if I can just 12v directly to it for testing in fear it may cause damage to them.

I do NOT remember hearing the fan come on when I attempt to use bucket functions or even if I throttle the thumb wheel. I read something somewhere that mentions this is related to the Hydraulics.

The RH does NOT have any other functions.. No boom lift, tilt, etc from the RH joystick. I removed the joystick/sensor assembly and debated disassembling to see if i can find anything visually wrong.. But I'm wanting to hold out some until I can try some further diagnosis.

If anyone is willing and have the free time with any suggestions on what I should look out for or test.. Or possibly a good schematic/trouble shooting guide to help diagnose this issue. I would really appreciate it.

I feel that this is probably something very simple.. But I guess it's usually always the case.. It's finding that 'simple problem' that can be a hairy process... Especially being new to the platform.

WHEN the issue is diagnosed and repaired. I will be sure to follow up with atleast the solution, incase someone else runs into this issue.. In hopes that it can help them too one day.


I appreciate anything that you all are willing to do to help guide me!

Thanks,
Shawn

P.S.. Yesterday I found a large, Grey single relay cover under the cab (next to the main ECM) when just doing a test on all electrical connections (unseating/seating and checking for corrosion). Which they all seemed to be fine.
When I removed the cover.. I did NOT see a relay installed. It is a 3 pin female plug. Red/Green/Black Wires (look to be 10-12ga)..

I am not sure what this relay would control.. (possibly IGN/start the loader when the cab is raised for diagnosis purposes using a specific OEM CAT pigtail?.. I doubt it is related to the RH joystick.. But it was noticed . So I wanted to ask.. I attached an image of it

your output signals are pwm outputs

Thank you for the reply.

I did use that schematic for finding the 12v and ground.

And yes I have my fluke 87-3. Which I actually didn't realize until this morning that it does test for duty cycle.. I thought it was only a feature on the FLUKE 87-5..but as I cycled thru some buttons.. I see the hz-% is displayed.

I will test this today.

Also, Calibration pins #4 and 5 for base.
Do you know if these Electro-Hydraulic joysticks need to be married to the ECM?
If so, I wonder if the PO has replaced the joystick but never got it accepted to the ECM. The tag date on the joystick does list 2012. So it makes me lean more toward this being the original.


I did 12v/ground test the solenoids yesterday.. And chose the downward-tilt solenoid.. I heard the click.. So then I applied 12v to the solenoid directly (bypassing the original harness) while the loader was running and I got movement!

I also did check the Hydraulic-electric FAN solenoid. Which does spin and when I applied 12v to the solenoid.. I saw that it slowed the fan down.. So that is functioning properly.

The circuitry for the solenoids is not getting signal. So it's either the joystick base sensor/solenoid not sending signal to ECM.. Or The ECM isn't sending signal to solenoids .. Or something else in the path is faulty.. I found this diagram (which I am not 100% sure that this is the correct for the 2012 CAT 246c). But it showed several items.. Like implement shut off solenoid, and switch (I did bypass the door switch just to see), pilot control valve... But it is difficult to find where some of these are or what they look like. .. Even when using the CAT manual.. It is a little difficult to see because it just shows a general location. Shows location #21 (engine).. Which is just the large block of solenoids where the bucket downward-tilt solenoid is.

I will just have to test each of them out.. Because the implent shutoff solenoid would cut all of the others off if I'm not mistaken.

I attached the diagram I found of the flow of operations on the Hydraulic system.. But I have a feeling it's not for the 246c. And the date says 2008.. So I'm not sure if the diagram is showing the older Hydraulic pilot control setup. Because I don't see the implement shut off solenoid in that diagram.

I sent you the Hydraulic Schematic

you said earlier that you had aux hydraulics
so that means all your safety interlocks are working and you have pilot oil available at the control valve .
I would concentrate on your PWM signals to the ECM and the out signals from the ECM

You could switch controls and see if it switches sides. The 6 pin plug is wired the same on both.

Chisumtrail said:

You could switch controls and see if it switches sides. The 6 pin plug is wired the same on both.

Click to expand...

Ahh I did not know this... The LH controls have 4 buttons on top.. So I wasn't sure if it would be the same... So I never tried it.

Maybe I'll give that a shot too..

I just got to the loader to do some more testing now.

Thank you

Mark250 said:

you said earlier that you had aux hydraulics
so that means all your safety interlocks are working and you have pilot oil available at the control valve .
I would concentrate on your PWM signals to the ECM and the out signals from the ECM
View attachment 217562

Click to expand...

Thank you mark.. I just got here to do some testing.

And ahh.. Yes.. You are correct.. That would mean they are working and when the solenoid is tested direct 12v..it does function the tilt.. So my apologies.. I guess I was thinking too hard about it.. Lol.. Been reading so much the past week trying to learn this machine as much as possible.. The simple things just slipped my mind.
I know this is a stupid question.. But for measuring duty with DMM.

On the joystick, One testing lead goes to signal wire.. The other to the ground wire on the shared connector? To rule out the joystick

If it sends signals.. Then the problem would be either circuit to the ECM or from ECM to solenoid?

I could OHM test from joystick connector to the corresponding pin on the ECM.
And the same from the output pin for that function on ECM to the corresponding pin at the solenoid.

Strangely.. After all the years of troubleshooting.. I actually have never measured for duty cycle . I guess this is a perfect opportunity to learn.. Would be very helpful in the future I'm sure.

Nige said:

I sent you the Hydraulic Schematic

Click to expand...

Thank you VERY much for the schematics and diagrams!

Update..

As Chismtrail suggested.. I swapped the controls from LH to RH. and 'boom'.. Had full movement (pun intended! Haha).


I also removed the base from each joystick to swap. In hopes that I could rule out the mechanical portion of the joystick (I'll call it, the pivot sleeve).
To where it finds signal from the pad tower on the joystick base computer board. There was a small crack in the plastic ring around the sleeve.. But swapping joysticks and bases only proved that the issue lies in the actual joystick base board.

How I believe this operates (may be incorrect.. But hear me out).
-The insulated tower pad from board, When energized.. Emits pulses of electro-magnetic signals thru the pad.

-The steel "pivot sleeve" in center of joystick, Picks up the magnetic signals. When the joystick is at rest.. All magnetic signals are equal. So it causes no action.

Ex.
Forward movement of the joystick, causes the pivot sleeve to be physically closer to the magnetic signal and the Aft is further. This variation of signal is then calculated/converted into a percentage/Duty cycle.
This input goes into ECM and if all interlocks give it the go.. It is an output to the solenoid.

I began removing the potting compound (I believe silicone based.. Which is just a mess). By mechanically scraping/picking/prying away at it (carefully).

To get a look at the circuitry. Just for curiosity's sake.. With hope that I can find a problem.

Now that I got most of it removed.. I am attempting to soak it in a solution to further remove it.. Hopefully I can get it ALL completely removed.

I snapped a few pics to post... But I'll follow up with more detailed pictures later. I did find that the two copper ground lugs that are attached to the board.. Both were very corroded and swollen.. I'm hoping that alone when cleaned up will do the fix.. But I still want to delve deeper into the board to really inspect with the microscope. I'm really hoping I can repair this.. And maybe the post can help some others out if it is successful!

QUESTION :
Does anyone sell this board separately?
Is it required to have it programmed/married to the ECM using CAT scan tool?
I did notice a small micro processor/IC chip.. Which stores memory... So I'm pretty sure programming is required, because I have swapped similar chips on automobile BCM's so that it can just be plug/play without going to dealer.
But I'm hoping not!

Comments, suggestions or advice is woefully appreciated!

Thanks!
Shawn

AFAIK nobody supplies individual components for those joysticks.

The main challenge you are facing is that most folks in equipment maintenance can't afford to do what you are doing for 2 reasons - either they can't afford the machine to be down for an extended period of time because it's costing them far more money than the price of a new joystick, or the fact that labour costs $100+ an hour. So if you add those two together it doesn't take long before you've blown way past the $800 cost of a new joystick assembly, probably about 4 hours of downtime give or take.

Shawn,

I have the exact same issue. Did you get it fixed? If not did you find a place that repairs or did you just buy a new one from CAT for $925?

Thanks,
Jared