Case CVX175 over CANBUS

Afternoon all

Another day, another CVX… but this time over CANBUS. Went out fully expecting to find the usual autosteer valve, but it had what I think is a Danfoss instead. I knew there was Danfoss documented in the wiki, but I thought I’d connect the CANBUS board (CommonRail’s design) I had with me instead, just out of interest.

With CAN3 connected to the green socket behind the seat, lo and behold, AOG is reading the wheel angle sensor and the wheel turns! Well, that was unexpected as I’d never had any luck with a CVX over CANBUS yet (and I know why, they had valves with Trimble autosteer modules already fitted, that were driving the valves over PWM).

So, this could be nice and easy… Per CommonRail’s guide, I needed:

CAN1-H = Pin C Diagnostic connector right rear pillar
CAN1-L = Pin D Diagnostic connector right rear pillar
CAN3-H = Pin H Diagnostic connector behind seat
CAN3-L = Pin J Diagnostic connector behind seat

Used my Flashing tool to download CommonRail’s CANBUS code to the Teensy: Releases · lansalot/AOGTeensyFlasher · GitHub

Went into the Service Menu in it and set it to 2 (For CaseNH) and P for 460800 serial.

So I wired them up, and couldn’t get the steering to engage. Nothing doing. Also, after a while, the tractor started throwing steering codes on the pillar, most notably code 15327.

Super-helpful guys on Telegram pointed out that I would need to go into the tractor’s own diagnostic menu and enable autosteer, so I bridge pins B and G on the diagnostic controller on the pillar (NOT the green one behind the seat) and turned the ignition on. I then went to U1/H1 and ran through the WAS calibration process (this is what 15327 means, basically that the WAS hasn’t been calibrated). This procedure was a bit fiddly to get going, especially the spool calibration, but the details are in the attached PDFs.
NH Steering Cal.pdf (4.0 MB)
New Holland H3 Config.pdf (1.7 MB)

I then went to U1/H3 and set “ch2” (navigation controller present) to “YES” and I was then able to engage steering !

And my custom case fits nicely in the usual place next to rear window, so nothing extra in the cab to annoy the operator.

All pretty easy in the end! Shame I didn’t notice my phone had focussed on the wiper instead of the stubble until the end… doh!


Link for the case, if you want to remix it: Onshape

STLs are here:

Very nice insight!

The older cvx’s that has a pwm valves the steer engage valve is still controlled from different computer(not the nav controller that drives the steer valves). Only way that trimble could activate that engage valve must be via can.

I’v been wondering if it is possible to activate steering via can and then use AIO to steer with PWM in these older cnh machines.
Do you think that is possible?

Funnily enough, I did a CVX230 some time back over PWM, but I couldn’t find the button that’s on the console via CANBUS (and that was with already knowing the button ID from CommonRail’s code). However, I’m wondering if it’s because the U1/H3 menu wasn’t set to have a guidance system present as this tractor had the right code straight away. Even sniffing for it with SavvyCAN I couldn’t identify the button, so maybe it’s just that pillar option after all.

I plan to revisit that machine, as it’s always bugged me that I couldn’t find it - and yeah, you’d have to add the code to the existing non-CANBUS AIO firmware to speak CAN, but it’s similar to how I did the Keya support, so really pretty simple.

Half-toying with going to see the machine today, but it’s an hour away and cold outside lol…

For these “old” tractors, the CAN engagement codes are not the same as for a CAN tractor. they are even different depending on the year… I found one you can test. I don’t seem to have found the central button, which is not practical. I instead use the trigger on the back of the handle.

EngagePuma.ino (4,6 Ko)

this code uses a simple nano it will need to be adapted and copied into the aio code. I use it to activate a PCBv2 remotely


Can you tell me what type of can bus plugs you are using? I know the socket is named ATC17-9-1939PN but which is the right plug for it?

All connectors here: Connectors · farmerbriantee/AgOpenGPS_Boards Wiki · GitHub

The one behind the seat is green, the one on pillar is black. They’re not the same, but I didn’t have the green plugs, so I just cut the top pin off as it wasn’t needed.

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