I have a pair of TB 4.12 Vescs and I am having some problems with them. The other day I hit a massive pot hole nearly sending me flying off my board. Lucky I rode it out just fine, the only issue my board instantly cut out. My Bluetooth module gives me a reading of 33v for my 12s battery. However after attempting to debug my battery is at 50v and the power leads going to each vesc at 50v. For some reason my Bluetooth module thinks it’s at 33v though. I am not sure how to check the voltage with the vesc tool but when I power on the vescs the slave vesc instantly gets very warm right by the can bus cable. I was trying to run motor detection on the 
master vesc and it would not pass. It’s also hard to connect to the vescs on my computer, it mostly cannot connect, I just got lucky once, usually I can just hit connect without and issues. Did something go wrong with my vescs?
@b264 you might have more expertise than I in this one
I feel you might have gotten a canbus failure?
@BudgetBuilder If you fill out your country, we can always be of more assistance.
Possibly @JohnnyMeduse or @seaborder might know more about this
Updated
It’s also odd because I can only connect to the vesc that has a very hot inductor, the master I cannot connect to. Note to self, avoid potholes.
Disconnect the vescs from power and can, and use the ohm-meter to check the resistance between canh and canl to each vesc. It should be 120. If it’s a lot less, the driver is probably busted.
That inductor is part of the 5V power supply to your vesc. If it is hot, you are probably putting a lot of heat into the vesc 5V rail. Not sure but I think can chip is powered by 5v. If the “broken” board power supply is detecting a short, it wont turn on. Maybe you just need one new can chip?
Thank you for your help. I will test the resistance in the upcoming days
The one that gets hot (Slave) reads 99ohm. The master reads about 13 ohm. For some reason the master between 5v and ground reads 105 ohm but on the slave between ground and 5v only reads 9ohm.
The master might be fried?
You put red on the power net and black on the gnd net? Try connecting the can lines (just can not power) between the two and then measure resistance 5V to gnd again. See if 5V to gnd is lower on the slave.
Kinda sounds like both are fried. Try and remove the can chip, or bend up the pins with a soldering iron and see if the vesc boots and runs ok, isn’t hot and all that.
Sound like a dead TVS diode
I get a voltage drop when testing both diodes in both directions. That shouldn’t be the case? The slave gets a reading close to 0 and the master about .1
I’m guessing they’re both bad then?
I don’t think they are both bad.
You can also check the voltage on the 5V rail. make sure it is around 5.17V (something like that)
They’re both 5.1v. So I found the issue. The master ground pad got disconnected, the ground power lead to the vesc. So I’m guessing something on the slave vesc broke when that got disconnected while I was riding
So would this fry the TVS diode on the slave?
Yeah could be, the 5V line probably got higher for a short period of time, blowing up the TVS (which is there to protect the 5V rail)
I finally got around to replacing that TVS diode and the vesc was working for a little bit. I was trying to run motor detection but it couldn’t complete the flux measurement. After letting it spin up the motor several times the vesc is now blinking red again giving a fault code.
Haha welp, just realized one year later these motor controllers still don’t work! One of them seems more promising than the other, they both get warm when plug in but one gets very hot to the point it flashes red and should not longer get power. I am putting together a little commuter board and need one controller for it. I really have no idea what’s wrong with either one. The more promising one seems to get warm in the can transceiver area next to the arm processor. When it powers on both the blue and green lights come on but I cannot connect it to the computer to save my life, I always get a serial port busy error. Otherwise I have a broken focbox that needs a trace repair lol.
If inductor is very hot Maby what ever is driving it has failed and its constantly short circuit just guessing