I have my OVMS unit (OVMS-33-7600G) configured and working fine when using the supplied OBDII to 9 pin D cable.
But my preference is to leave the OBDII port free and connect the OVMS to the TCU CAN bus.
So, per the instructions I de-pinned pin 6 & 7 from the 40-way connector as well as T-ing off a +12v and Ground connection, and left the TCU connected.
I then connected the de-pinned CAN bus wires to Can1 (pins 2 & 7) and the supply and ground to pins 9 & 3 on the 9 pin connector.
But I can't get it to work. It just doesn't seem to be communicating at all. I tried it with the car both on and off. I also tried it with 2016 and 2017 year settings.
Unless I've misunderstood, this should just work. At this stage I am deeming "not working" to just mean it can't read the SOC.
I even delved into the TCU box and was able to confirm the CAN pins I used did indeed connect to a CAN transceiver. I noticed there was a second transceiver on pins 26 & 27, so in desperation I tried those instead, but the result was the same.
Maybe I need more than just the one CAN connection? I read about a wake signal but am not sure if that applies to my car, or even if it does, should only be needed for remote A/C activation? I also read that Nissan made changes in 2016 and I believe (but aren't certain) that mine was manufactured after that change The TCU label says: "TCU GEN3 3G".
Now I am at a loss and was hoping someone has some suggestions or can point me in the right direction.
Problems with advanced installation of OVMS on UK 2016 MY 30kw Leaf Tekna ZE0
26 April, 2026 - 09:16
#1
Problems with advanced installation of OVMS on UK 2016 MY 30kw Leaf Tekna ZE0
It was said here (https://www.openvehicles.com/node/3809 and https://www.openvehicles.com/node/4471) before, that TCU doesn't have all necessary connections for drop-in replacement, you still need EV-CAN (only at OBD or via CAN-gateway)
Thanks sasha,
I had seen those posts, and have been trying to interpret what they mean in terms of what I need to do. Unfortunately I haven't be able to find any wiring diagrams for my Leaf.
You said: "TCU doesn't have all necessary connections for drop-in replacement, you still need EV-CAN (only at OBD or via CAN-gateway)".
That can't mean that the TCU doesn't have the right connections to be able to replicate the NissanConnect EV functions?, since the TCU is the thing that did that?
So, I'm assuming CAN-gateway is on one of the two CAN buses I have in my TCU harness? Would you know which one?
When I look at the photo of the harness in the docs here, it is similar, but there are enough differences to pins and wire colours to make me doubtful. I've attached a photo of mine for comparison. So, I can't be sure if any of the other connections are relevant to me, such as the "Wake Up/Ign", or if I even need them.
Any help would be greatly appreciated.
I feel you might be going about this the hard way. I installed OVMS on my 2016 30kWh Leaf a few weeks ago, and like you I also wanted to keep the ODB-II port available.
I simply bought a splitter cable which has a panel mount socket which can click into place where the original socket fits. This was only £11 from amazon:
https://www.amazon.co.uk/dp/B073Y519FG
Then instead of trying to de-pin the TCU cable I simply cut pins 6 and 7 inside the TCU - which is a lot easier as it is trivial to get the case open and snip the back side legs of the connector with side cutters.
This is all working perfectly for me and means I have not had to mess with any of the original wiring harness of the car.
For all features to work properly the OVMS module needs to connect to both CAN bus networks, which the Leaf specific cable for the OVMS module does.
Hope this helps.
Regards,
Simon
I think you are right, that is my best route. I will order one of those leads. It's working perfectly plugged into the OBDII so with the addition of that lead I can hide it all away as I originally wanted.
I didn't mind doing the hard work of the other method, but it was very frustrating to finish it only to find it didn't work and I couldn't figure out why. Although you said it needs to be connected to two CAN buses, so that could well have been the problem.