Discussion in 'Tin Foil Hat Lounge' started by Mindgrinder, Jun 29, 2013.
I'm buying an old car from the 50's... Screw technology.
If I were to buy a NEW Auto, the VERY first thing I would do, is to disconnect the Cellular Antenna, from the BlackBox Cellular Modem that is tied into the Vehicle's, onboard Comm Buss. You can't disconnect the Modem, from the Buss, as it is REQUIRED for the Buss to operate the Vehicle. HOWEVER. You can disconnect the Antenna, from the Modem, which keeps ANYONE, from coming in thru the Cellular Connection, and messing with the Vehicle's OnBoard Computers. If they can't get in, then they can't monitor the GPS, or any of the OnBoard Systems connected to the Buss. "Oh Darn, Officer, You couldn't stop my car Remotely, because you couldn't hack into my Car. To bad, for You... and Hurrah, for Me!"
What prompts you to say that? ( seriously, just inquiring). I am a bit familiar with the bus networks on Chrysler pickup trucks and many medium and heavy duty vehicles. They employ multiple networks (for example the diesel engine connects to three different networks). These networks are basically derivatives of the Bosch CAN network released in I vaguely recall 1986. There have been speed upgrades and protocol definitions over the years leading to the SAE J1939 standards and J1979 standard. And there are manufacturer proprietary protocols for some internal networks but the hardware layers on these are generally similar if not the same. These networks are designed to be fault tolerant and if a device is disconnected from the network bus, the network itself keeps working. CAN bus errors that shut down the network generally only occur if a device fails in such a way that it shorts the comm lines to ground. If a module on the network even looses power the network still functions for the other devices. At least in the systems I know.
So the question then becomes is there information required from the modem in order for some system to function AND is there no feasible backup operation mode? Contingency operation is a big big deal to mitigate warranty costs as manufacturers hate paying for tow trucks. Only then would disconnecting the modem shut down the vehicle. But I think it unlikely there would be that information requirement from just a modem. But like I said, I am familiar with trucks and maybe cars are a bit different but I know the J1979 comm network on vehicles under 14,000 pounds isn't much different and functions similarly to J1939 with respect to the physical layer of the network.
So, I'm thinking it might be as easy as just pulling the fuse for the modem/cellular system. There might a dash light or message but not an OBD MIL as the regulations reserve it for only emission related systems and devices used to diagnose emission related stuff.
On many of these systems, the Cellular Modem, gives a HeartBeat Signal to a controller, that must see it or it flags the system as Non-functional.... The only SURE way to defeat the Cellular Modem, is to kill it's RF Feed, by disconnecting the Antenna, which simulates driving in an area with NO Cellular Service. Any other measure may cause things not to work properly, and you are NEVER sure that you are NOT going to have issues. lack of Cellular Service, will NEVER cause the system to error. ..... Check OnStars Controller, the Modem must be there....
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