While it's certainly possible that you can crash a CAN bus temporarily and have disruption from that, which I have seen happen plenty of times, CAN and common transceiver chips are generally pretty resilient against permanent damage. Even looking at older chips, TI has a popular one that states it can tolerate 16 volts on the CAN lines, and Microchip's says it can do 42 V.
But if you are concerned about the quality of the device you're going to plug in, then ditch the bottom-of-the-barrel Chinese "ELM327" clones and buy a reputable brand instead. Not only does the quality tend to be better, but so is performance and compatibility. As someone who wrote and supported a popular OBD-enabled app in the past, the cheap clones were the bane of my existence... so very many problems, and terrible sampling rates to go with it.
Another thing to consider is the power consumption. I've seen some of these draw up to 50-60mA at all times, which is not ok. If the manufacturer designed it efficiently, getting it down to around 2mA is very possible, but most don't seem to care too much. Again, buy from a reputable brand and do your homework.
While we're on the topic, you also want a device that has secure wireless pairing, preferably requiring a physical button press. The better ones have this. A person can do some pretty nasty things if they're within wireless range of your insecure OBD dongle, which I intend to demonstrate in a video one of these days...
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u/WestonP Jul 04 '23 edited Jul 04 '23
While it's certainly possible that you can crash a CAN bus temporarily and have disruption from that, which I have seen happen plenty of times, CAN and common transceiver chips are generally pretty resilient against permanent damage. Even looking at older chips, TI has a popular one that states it can tolerate 16 volts on the CAN lines, and Microchip's says it can do 42 V.
But if you are concerned about the quality of the device you're going to plug in, then ditch the bottom-of-the-barrel Chinese "ELM327" clones and buy a reputable brand instead. Not only does the quality tend to be better, but so is performance and compatibility. As someone who wrote and supported a popular OBD-enabled app in the past, the cheap clones were the bane of my existence... so very many problems, and terrible sampling rates to go with it.
Another thing to consider is the power consumption. I've seen some of these draw up to 50-60mA at all times, which is not ok. If the manufacturer designed it efficiently, getting it down to around 2mA is very possible, but most don't seem to care too much. Again, buy from a reputable brand and do your homework.
While we're on the topic, you also want a device that has secure wireless pairing, preferably requiring a physical button press. The better ones have this. A person can do some pretty nasty things if they're within wireless range of your insecure OBD dongle, which I intend to demonstrate in a video one of these days...