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Dala
Posts: 392
Joined: Sun Oct 28, 2018 11:24 am
Delivery Date: 01 Jan 2015
Leaf Number: 316851
Location: Finland
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Re: TCU Disconnect Service

Fri Dec 18, 2020 9:14 am

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.

CML
Posts: 7
Joined: Wed Dec 16, 2020 10:31 am
Delivery Date: 12 Dec 2020
Leaf Number: 5974
Location: Olympia, WA, USA

Re: TCU Disconnect Service

Fri Dec 18, 2020 9:29 am

Dala wrote:
Fri Dec 18, 2020 9:05 am
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.
Rescued 2011 Leaf SL QC, 80k mi 55% SOH, OVMS v3
2018 Ram ProCity campervan w/ Victron off-grid solar power

User avatar
Dala
Posts: 392
Joined: Sun Oct 28, 2018 11:24 am
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Leaf Number: 316851
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Contact: Website

Re: TCU Disconnect Service

Fri Dec 18, 2020 9:44 am

CML wrote:
Fri Dec 18, 2020 9:29 am
Dala wrote:
Fri Dec 18, 2020 9:05 am
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!

CML
Posts: 7
Joined: Wed Dec 16, 2020 10:31 am
Delivery Date: 12 Dec 2020
Leaf Number: 5974
Location: Olympia, WA, USA

Re: TCU Disconnect Service

Fri Dec 18, 2020 10:40 am

Dala wrote:
Fri Dec 18, 2020 9:44 am
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)
Rescued 2011 Leaf SL QC, 80k mi 55% SOH, OVMS v3
2018 Ram ProCity campervan w/ Victron off-grid solar power

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Dala
Posts: 392
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Re: TCU Disconnect Service

Fri Dec 18, 2020 11:10 am

CML wrote:
Fri Dec 18, 2020 10:40 am
Dala wrote:
Fri Dec 18, 2020 9:44 am
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-Mal ... SwOXJex5Vz

With that type of cable you can hide the OVMS install completely!

CML
Posts: 7
Joined: Wed Dec 16, 2020 10:31 am
Delivery Date: 12 Dec 2020
Leaf Number: 5974
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Re: TCU Disconnect Service

Tue Dec 29, 2020 1:39 pm

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...
Rescued 2011 Leaf SL QC, 80k mi 55% SOH, OVMS v3
2018 Ram ProCity campervan w/ Victron off-grid solar power

JohnGalt69
Posts: 30
Joined: Mon Jan 23, 2017 6:56 pm
Delivery Date: 24 Mar 2013

Re: TCU Disconnect Service

Thu Sep 02, 2021 4:12 pm

Lothsahn wrote:
Thu May 31, 2018 10:28 am
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?

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Stanton
Posts: 2501
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Leaf Number: 7458
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Re: TCU Disconnect Service

Fri Sep 03, 2021 6:15 am

JohnGalt69 wrote:
Thu Sep 02, 2021 4:12 pm
Lothsahn wrote:
Thu May 31, 2018 10:28 am
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.
2011 Blue Ocean SV w/OVMS
12v LiFePO4 battery w/Antigravity Battery Tracker
FIAMM 74100 horns/Wet Okole seat covers/Tor's heater mod/Dala's CAN-bridge
Lizard Pack (Rev E) installed @51 months/41k miles
40 kWh Pack (Gen2) installed @115 months/84k miles

zmonev
Posts: 2
Joined: Wed Nov 03, 2021 7:35 am
Delivery Date: 03 Nov 2021

Re: TCU Disconnect Service

Wed Nov 03, 2021 9:07 am

[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.

User avatar
Stanton
Posts: 2501
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: TCU Disconnect Service

Thu Nov 04, 2021 6:35 am

zmonev wrote:
Wed Nov 03, 2021 9:07 am
[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 (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)!
2011 Blue Ocean SV w/OVMS
12v LiFePO4 battery w/Antigravity Battery Tracker
FIAMM 74100 horns/Wet Okole seat covers/Tor's heater mod/Dala's CAN-bridge
Lizard Pack (Rev E) installed @51 months/41k miles
40 kWh Pack (Gen2) installed @115 months/84k miles

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