THE NEED:
The OVMS is already a very good product, but we can make it easier for right hand drive Nissan Leaf ownwers to get started. New Zealand imports good quantities of used RHD Leafs from Japan. They are also found in the UK and Australia. At the same time we could remove an unnecessary item from the OVMS hardware offering.
The OVMS documentation specifies the use of special cable 1779000 for the Nissan Leaf (https://docs.openvehicles.com/en/latest/components/vehicle_nissanleaf/docs/index.html#:~:text=Vehicle%20Cable,Cable%20for%20OVMS). This is known as a 'right' cable because of the way the cable exits the OBD-II plug. There is no special 'left' cable for the Leaf. The 'right' might well suit Left Hand Drive (LHD) Leafs but it is NOT the best choice for right hand drive (RHD) Leafs.
THE DETAIL:
The OBD-II socket on the RHD Leaf is located under the steering column facing downward. The edge that contains the polarising notch (closest to pins 9 to 16) has been observed as always facing the right of the car. With this orientation, the recommended cable (1779000) exits the OBD-II plug parallel to the steering column heading toward the driver and the rear of the car. It would be better if the cable exited the connector in the opposite direction, namely away from the driver and to the front of the car. In this orientation the cable can be restrained properly.
Following a trip to the local car yard I can confirm, having examined 6 RHD Leafs including 24kWh, 30kWh and 40kWh models from 2016 to 2018, that every one of them has the OBD-II connector fitted the same way.
SOLUTIONS:
The following possible solutions vary first from the most desirable result to the least effort:
1) Cable standardisation
Instead of special cable 1779000, a firmware change would allow the Leaf to use the standard OVMS cables used in most other vehicles:
"OBD-II to DB9 Data Cable for OVMS (1441200 right, or 1139300 left)".
The LHD Leaf would use the right cable and the RHD Leaf would use the left cable.
The special Nissan Leaf cable is identical to the right standard cable other than the exchanging of primary and secondary CAN busses. The change to OVMS firmware should therefore exchange the functions of the primary and secondary can bus connections when configured for a standard cable - but not when configured for the legacy Leaf cable.
A means of sensing an incorrect configuration or cable might be useful to assist installation.
2) Yet another cable
It would be possible for OVMS to specify a 'left' Nissan Leaf cable with the same connections as the 1779000 but with cable entry on the opposite end of the OBD-II connector (as pictured for the 1139300). Documentation would have to recommend its use for right hand drive Nissan Leafs.
This means one more cable to manufacture and stock. Unlike solution 1 above, this solution does nothing to simplify matters for first time users.
3) Cable modification:
My solution for myself was to NOT buy Leaf cable 1779000 (which could be described as a 'right' cable) but instead buy the standard left cable 1139300 and a replacement DB9F connector (available from Fasttech as SKU 9668959). I cut the original DB9 conneoctor from the cable assembly and wired the replacement connector according to the 1779000 pinout (as detailed on the Fasttech website) before testing then using it.
This worked for me - it suited my skill set. Others might prefer solution 4.
If documented, others could use this solution.
4) Socket remounting:
I'm told it is possible to unmount the OBD-II socket from the car and reaffix it in a different orientation. This is not my preferred option - I would rather my prized transportation investment be left as original as possible.
I've not found any documentation on socket remounting or on any other aspect of mounting the OVMS.
ACTION:
I'm new to this group and would need a lot of help to see any of the proposed solutions actioned. It seems I will be of little use unless I can learn to use git, but at least I now have a reason to start on that path (when time allows). I understand that none of the solutions suggested above can ever be pulled into the system, whoever issues a pull request, unless the project maintainers agree that it is the way forward. I guess this means we need buy in from the project maintainers as to which (if any) of the solutions I've listed are deemed worthy of proceeding with.
So, where does this issue and its proposed issues fit with the project maintainers?
I'm not sure I see your issue unless the OBD port is mounted differently on UK compared to JPN originated ones?
Here is how our's looks - the OBD port faces outwards, not downwards - and the next image shows how the cable works best this way.
If you zoom into the first image, you will see clips on the white OBD plug itself - if you push these in (top and bottom) you can remove the plug and rotate it 180 degrees if needed.
I no longer use this setup though - I sourced an OBD splitter which slots exactly into the Leaf's fittings, so all the OVMS cabling is now hidden behind the trim, and I still have an accessible OBD port for Leafspy etc.
In general, so long as the firmware change was backwards compatible, it will be accepted into the mainstream code. Something like a config setting, defaulting to the old approach.
Perhaps better to make the change generic (done at the vehicle.{h,cpp} level) to allow CAN1, CAN2, CAN3 to be re-mapped dynamically when the vehicle module is loaded/initialised.
That said, I have heard of a very few similar cases over the years, and it seems more likely that your OBDII port has simply been installed the wrong way round. The connector in the Leaf is supposedly a simple click-in, and easy to get wrong when working on the dash.
Indeed the OBD-II mounting is quite different. Being in a confined space, it is also difficult to photograph in context, but I do have a photo.
Unfortunately I can't figure out how to paste it here. Any advice?
The best bet would be to upload the image to a free image hosting site (many available, I tend to use Imgur) and share the link.
View of the foot well of a RHD 2016 30G Leaf ex Japan (follow link). A 'left' OVMS cable (modified for the required Leaf pinout) can be seen inserted in the OBD-II socket (highlighted by the red oval).
https://www.dropbox.com/s/o8qjlbmidavmm5i/Leaf%202016%2030G%20Japan%20OBD-II.jpg?dl=0
I did try using the editor's 'image' icon but it failed to show the image for me. Imgur's terms of use prevented me creating an account there. That is why you are stuck with a hyperlink to the picture.