TCU Disconnect Service

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I looked at the FSM,
The P31C2 DTC is related to a single wire going between the VCM and TCU. There should be a pulse on this wire once the vehicle starts, and if this is missing the fault code will be set. So there is unfortunately no way to avoid this DTC with CAN message generation.

I would still disable the TCU and run with codes active if I had one.
 
Dala said:
Nope, according to schematics the TCU is on the same EV-CAN as the battery (and the OBD2 port)

Thanks for all this info! So in theory I could connect my OVMS (or any other OBD2 adapter) to pins 1-2 (battery +/-) and 9-10 (CANbus) of the TCU connector, rather than have it occupying the OBD port. I may try this once my OVMS arrives, as it would be nice to be able to run LeafSpy without disconnecting OVMS. I also wonder if doing so would alleviate any of the DTCs.

The U1266 DTC for the MultiAV touchscreen not detecting the TCU does not come back after being cleared, even after a hard cycle of the 12v battery. The other three EV/HEV DTCs I list above come back immediately.
 
CML said:
Dala said:
Nope, according to schematics the TCU is on the same EV-CAN as the battery (and the OBD2 port)

Thanks for all this info! So in theory I could connect my OVMS (or any other OBD2 adapter) to pins 1-2 (battery +/-) and 9-10 (CANbus) of the TCU connector, rather than have it occupying the OBD port. I may try this once my OVMS arrives, as it would be nice to be able to run LeafSpy without disconnecting OVMS. I also wonder if doing so would alleviate any of the DTCs.

The U1266 DTC for the MultiAV touchscreen not detecting the TCU does not come back after being cleared, even after a hard cycle of the 12v battery. The other three EV/HEV DTCs I list above come back immediately.

Keep in mid that the OVMS needs both CAR-CAN and EV-CAN to function properly, so if you are relocating it you need both CAN channels. Easies to just use an Y-OBD2 splitter and hide everything behind the OBD2 port, that way you have the real OBD2 port free!
 
Dala said:
Keep in mid that the OVMS needs both CAR-CAN and EV-CAN to function properly, so if you are relocating it you need both CAN channels. Easies to just use an Y-OBD2 splitter and hide everything behind the OBD2 port, that way you have the real OBD2 port free!
Is the OBD2 port under the dash just a female-female connector? You're saying I can put the Y splitter behind the OBD2 port? Would you mind posting a link for a part? (sorry I'm new! computer nerd, not car nerd)
 
CML said:
Dala said:
Keep in mid that the OVMS needs both CAR-CAN and EV-CAN to function properly, so if you are relocating it you need both CAN channels. Easies to just use an Y-OBD2 splitter and hide everything behind the OBD2 port, that way you have the real OBD2 port free!
Is the OBD2 port under the dash just a female-female connector? You're saying I can put the Y splitter behind the OBD2 port? Would you mind posting a link for a part? (sorry I'm new! computer nerd, not car nerd)

Yes, something like this works wonders https://www.ebay.com/itm/OBD2-16Pin-Male-to-Dual-Female-Splitter-Adapter-Extension-Cable-Y-Cable-Black/392808629040?hash=item5b75380330:g:UB0AAOSwOXJex5Vz

With that type of cable you can hide the OVMS install completely!
 
Update: On my 2011, I went ahead and disconnected the TCU entirely, and have had no issues or noticeable changes in vehicle behavior for almost a week. If you are having 12v battery drain issues, or have a now-useless 2G TCU like me (Carwings update says "No service") then I'd recommend disconnecting it.

To recap, here are the OBD DTC codes that persist:
P31C2 00C0 EV/HEV TCU EVC-273
U1000 00C0 EV/HEV CAN Comm Circuit
P31B8 00C0 EV/HEV CAN Error EVC-287
(if you find your vehicle being serviced, it would be good to let them know these codes are "normal" for your car)

An additional code from the AV system can be cleared and remains cleared even after 12v battery disconnect:
>U1266 0209 MULTI AV TCU Conn AV-92

Thanks Dala for the tip on the OBD Y adapter! The one I ordered does not have the locking tabs, so it's hanging out of the OBD port hole a little bit, but it's still a nice clean OVMS install. I may replace the adapter at some point.

Related to 12v battery drain, as I was installing the OBD Y adapter for my OVMS, I found a GPS tracker under the dash! :roll: I noticed three splices on the wires going to the OBD port, leading to a small box sloppily zip-tied to a wiring harness. Apparently US Nissan dealers install these SkyLINK GPS trackers for "inventory control" and "theft location" aka repossession. If your car is in the US or came from the US, it's worth a good look around under the dash...
 
Lothsahn said:
2) Disabling the TCU (even if done properly) does NOT disable the nag screen on the 2011/2012 cars. Even with no TCU, the car still asks you to accept sending carwings data--and no fix. Thanks Nissan. If anyone knows a way around this, please let me know.

Has anyone found a way to completely disable the nag screen?
 
JohnGalt69 said:
Lothsahn said:
2) Disabling the TCU (even if done properly) does NOT disable the nag screen on the 2011/2012 cars. Even with no TCU, the car still asks you to accept sending carwings data--and no fix. Thanks Nissan. If anyone knows a way around this, please let me know.

Has anyone found a way to completely disable the nag screen?
Nope. My TCU is gone baby gone (installed OVMS) and I still get the nag screen.
 
[MOD: fixed 24kW => 24kWh, just to save cwerdna a post]

Hi guys I have a Nissan Leaf 2015 24kWh in the UK so it is RHD vehicle. I bought OVMS and set it up and connected it up alright. It all works just the A/C control does not show on the app at all. I disconnected the white connector on the TCU but still does not work.
My question is do I have to disconnect the grey connector for it to work or white one is enough.
Also do i have to disconnect the negative cable on the 12v battery as well?
Thanks a lot for your help in advance.
 
zmonev said:
[MOD: fixed 24kW => 24kWh, just to save cwerdna a post]

Hi guys I have a Nissan Leaf 2015 24kWh in the UK so it is RHD vehicle. I bought OVMS and set it up and connected it up alright. It all works just the A/C control does not show on the app at all. I disconnected the white connector on the TCU but still does not work.
My question is do I have to disconnect the grey connector for it to work or white one is enough.
Also do i have to disconnect the negative cable on the 12v battery as well?
Thanks a lot for your help in advance.
If you post this question in the thread I started here (https://mynissanleaf.com/viewtopic.php?f=31&t=32715) about OVMS, I will address it directly. I am in the process of updating my post about remote climate control (very timely)!
 
I have a new to me 2013 SL and the CARWINGS Unit ID information screen gives a Unit ID and a TCUID. However, when I took it to the dealer they said that the P7332 recall had already been performed. So rather than deal with the dealer anymore, I'll just follow this thread's advice and do it myself and replace the cabin air filter while I'm at it.
 
JohnGalt69 said:
Lothsahn said:
2) Disabling the TCU (even if done properly) does NOT disable the nag screen on the 2011/2012 cars. Even with no TCU, the car still asks you to accept sending carwings data--and no fix. Thanks Nissan. If anyone knows a way around this, please let me know.

Has anyone found a way to completely disable the nag screen?

https://github.com/Vasioky/ovms-nowarning-plugin
 
Olsonist said:
JohnGalt69 said:
Lothsahn said:
2) Disabling the TCU (even if done properly) does NOT disable the nag screen on the 2011/2012 cars. Even with no TCU, the car still asks you to accept sending carwings data--and no fix. Thanks Nissan. If anyone knows a way around this, please let me know.

Has anyone found a way to completely disable the nag screen?

https://github.com/Vasioky/ovms-nowarning-plugin
Good to know, but not sure I understand all the instructions.
One part is uploading a file (via the OVMS module console?), but the other is a hardware mod (to the adapter cable?).
You tie pins 11 & 3 on the CAN connector to pins 8 & 6 (respectively) on the DB-9 connector? So you really need to "add wires" to the existing cable??
 
I just got my SL and I have a stack of upgrades to do. This is one but I haven't even installed the OVMS yet. I disconnect the TCU later today when air filter shows up. That said, it makes sense that the OVMS would need access to the AV CAN bus in order to shutdown the nag screen which is fundamentally an AV thing.

Dala did the original hardware hack in 2020 and Vasioky wrote the plugin.

https://www.mynissanleaf.com/viewtopic.php?p=585920#p585920

I wonder if this mod would also give the OVMS access to the AV's GPS receiver. Yes, I know it has its own.

BTW, watching the Xanavi CarPlay videos, he seems to have shut off the nag screen. That is on my upgrade list.

https://www.youtube.com/watch?v=MMSpanwuKgc
 
Dala has some software, LeafEnhancer, and he's been working on deleting the nag screen. So what's in the video may be some working in progress but he hasn't released NagscreenRemover yet.

https://github.com/dalathegreat/LeafEnhancer-UserManual
 
Olsonist said:
Dala has some software, LeafEnhancer, and he's been working on deleting the nag screen. So what's in the video may be some working in progress but he hasn't released NagscreenRemover yet.

https://github.com/dalathegreat/LeafEnhancer-UserManual
If that NagscreenRemover is associated with his CAN bridge, that might be thing that finally gets me to upgrade the firmware. I say "might", because it's not trivial (I don't have a programmer) and there's always risk involved when I've been working without issues for over 2 years now.
 
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