I've been fiddeling around with a Bluetooth ELM327 device I bought a few months ago and am able to get standard OBD information like vin, rpm, speed, etc. But as I just read about recently, OBD-II and CAN are not the same.

I've tried to sniff on my CAN bus with the AT MA command, but I get no response, so I guess the CAN network is decoupled from the OBD-II interface. Is there any chance to get access to the CAN network? Or might I need a different device to do so?

Maybe this information helps: I have a 2011 Škoda.

  • 1
    \$\begingroup\$ Several things to think about. The vehicle may have more than one CAN bus which could very well carry separate traffic on each. There may be redundant busses used for critical safety related paths. Access to the vehicle busses may mean having to break into a wiring harness or tap onto an end point. If doing this be aware of how bus terminations work and where they may be located. \$\endgroup\$ Apr 30, 2015 at 13:28
  • \$\begingroup\$ What of model of Škoda? Citigo? Yeti? \$\endgroup\$ May 5, 2015 at 18:53
  • \$\begingroup\$ OBD is a protocol based on CAN and companies provide access to only this data as it is dangerous to interfere with Vehicle traffic. You may not find a "Port" to access Vehicle Bus like you have one for OBD... So without harming your car and cutting cables, No, You can not access the Bus! \$\endgroup\$
    – Swanand
    May 7, 2015 at 8:25

1 Answer 1


There is CAN bus exposed on OBDII pins 6 and 14: obdii connector pinout
image sourced via google images search

More likely the issue is communicating with the ELM interface. The ELM is simply a PIC microcontroller programmed to respond to modem-like commands and then interface with a CAN controller and transceiver. You will need to find software that interacts with the ELM and can give you a data dump.

The data you mention in the question are most likely on the CAN and/or K-line pins of the OBD connector. Note also it is common for there to be 2 or more CAN busses which may operate at different speeds. Only a diagnostic / ecu bus will be on the OBD pins 6+14. You will need to tap into the wiring for the body, entertainment, or instrument CAN busses if they exist.


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