Making Requests for data on the CAR-CAN bus

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garygid

Well-known member
Joined
Apr 21, 2010
Messages
12,469
Location
Laguna Hills, Orange Co, CA
Apparently all recent model ICE cars sold in the USA are required
to have a CAN bus on pins 6 and 14 of the OBD connector.

Our LEAF also has its CAR-CAN bus on those pins.

Perhaps some of the data on the typical ICE bus is the same
as the data on the LEAF's CAR bus.

Even more interesting is the possibility that writing a data-Request
message to the LEAF's CAR bus might be done in the same way
that it is done in the typical ICE vehicle.

To investigate this, I bought a couple of OBD2 readers that can
read and write to the typical 500k baud CAN bus, and I am
learning about how the typical ICE does Data-Requests, hoping
that Nissan used the same methods in the LEAF, rather than
re-inventing a new method for the LEAF.

Sure, the codes and are likely to be different, but the general
mechanism might be basically the same.

Regular ICE OBD2 diagnostics devices send a 0x7nn code to
request a response from all the listening Control Units.

First, I intend to hook up the GID-Meter to an ICE and log the
messages on the CAN bus. Perhaps something like the
accelerator pedal position is similar to the LEAF.

Then, I will hook up BOTH the GID-Meter Logger, AND the ICE OBD2
device, and log what the OBD2 "reader" writes to the bus, and
the responses it gets.

Has anybody else tried something like this?
 
Gary,

Did you ever get anywhere with this experiment? I too am hopeful that running a "standard" ICE CAN-bus device on the CAR-CAN bus might yield some useful information, although my 5-minute experiment thus far was unsuccessful.

Updates appreciated. Others with knowledge, please feel free to chime in...
 
I have logged all (I think) of the passive (just listening) Messages on the
LEAF's CAR-CAN bus, using a "standard" CAN bus device, carefully setting
Read-and-Log mode where it does not try to write any Requests to the bus.

One member has made some progress in writing requests, and
then receiving and decoding the responses. But, not enough for
public disclosure yet.

Once somebody gets a LeafScan, and logs the messages while
the LeafScan is making requests, it is likely that we will learn more.

Then, hopefully, the rabbit will be out of the sack. :D
 
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