Phil,

I suspect that the primary reason to switch EV bus to CAR bus was so that they could use standard hardware (wifi, bluetooth OBDII). While the active polling technique works, it is problematic when the car is asleep (each poll request seems to fire a little relay to wake up the bus).

For OVMS, 95% of what we want is on the EV bus, and we are not worried about using standard OBDII hardware. It really seems more sensible to be on that bus, and then use active polling (the other way) to get what we want from the CAR bus if needed.

Regards, Mark.

On 17 Jun, 2014, at 12:32 am, phil hochstetler <phil.hochstetler@gmail.com> wrote:

I don't know all the details, but I have followed some of the development of the can bus hardware monitoring for the Leaf.
Much of the first attempts were using the EV can bus, but they discovered you can get one of the ECU's to forward requests/responses for you and thus
they dropped making EV can bus requests and can use the regular car can bus.  This makes all the cables standard.

If you dig around on the leaf forum (or ask garygid) you can get all the details.

Phil H.


On Sun, Jun 15, 2014 at 8:15 PM, Mark Webb-Johnson <mark@webb-johnson.net> wrote:

I've ordered a bunch of cables suitable for CAR and EV can buses of Nissan Leaf. Pinout is:

Pinout B

J1962-M   DB9-F   Signal
4         3       Chassis/Power GND
6        5      CAN-H (alternate CAN)
14       4      CAN-L (alternate CAN)
13        7       CAN-H (primary CAN)
12        2       CAN-L (primary CAN)
16        9       +12V Vehicle Power

J1962 end should be MALE plug with right angle cable. DB9 end should be FEMALE.
Both ends should be enclosed in shells, and cable should be 1metre in length.

The wiring brings J1962-M pins 13 and 12 (EV can bus) through to our standard OVMS v2 can bus pins. It also brings the normal CAR can bus through on DB9-F pins 5 and 4 (for future use on any dual-can enabled OVMS module, or easy re-wiring at the DB9 end).

Cable itself as per our standard naming:


For simplicity, I'll ask Fasttech to handle logistics for these, as usual.

Regards, Mark.


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