I'm gonna gamble on the resistance load being inaccurate. Tons of jobs got turned over early with improper loads. You should have 60 Ohms on your CAN channels, High to Low (Blue wire with white stripe to white wire with blue stripe).
Multi car groups, people often forgot to take off the HC1T and HC1C jumpers. I usually take them off the master car, and all slaves up to my final car, which stays on. If repeaters are used, I sometimes take the jumper off the A channel to get loading correct. Remember it's supposed to be an End Of Line resistor when you leave something on, so make sure it's actually the end of the line.
90% of my odd, intermittent, hard as hell to duplicate, CAN issues have been due to piss poor CAN loading.
Absolutely!
And don't think because it has been like that for a year, 2 or whatever it must be right. I just found one last week that was one of the first 32 bit 50-04s, the car channel had loading resistors on the CPU, the machine room CNA, the car CNA, and both door operators! Worked fine until now.
Also important to remember that just because you have 60 ohms does not mean it's loaded correctly. Better to think of it like you should have 120 ohms of termination resistance on each end. Kind of what you just said.
