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Mount Vernon, WA | Note: My comments below are general in nature. I do not have access to the wiring diagrams for this particular machine, however the advice below applies to the CAN networks of the vast majority of machines today.
This is what happens when a company shoves all of their modules onto one CAN network, as Deere does on at least some of their machines. PACCAR takes the opposite extreme; they must have close to a dozen or so networks on their trucks.
With the battery disconnected, use an ohmmeter and check resistance between pins C&D of the diagnostic connector. You should see 60 ohms. If you do, the termination resistors are OK. If you see 120 ohms, you have one missing or damaged (open) resistor. If your meter reads "OL" or a super high number then both resistors are missing or damaged.
If you have a friend who has access to a scope, attach a set of voltage leads at pins C&D of the diagnostic connector and look closely at the pattern. Someone who has looked at CAN waveforms before should know what good and bad patterns look like. If you see a bad pattern, simply unplug controllers one at a time until it goes away. Or, wiggle the CAN harness and see if the pattern changes. | |
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John Deere can bus faults. Shutting tractor down
