2018-2023 Nissan Leaf wiring harness info

[gellis12]

Per my discussion with @sshane, I'm adding some info here:

For some brief context, the Leaf does not have you connect the Comma wiring harness adapter at the LKAS camera, it gets connected at the ADAS computer module instead. This module is typically located behind the glovebox on the passenger side, though it is sometimes located behind the dashboard in a small number of markets.

The ADAS computer does not have constant fused 12v power supplied to it, but it does get switched 12v (Ref 1). Currently, this means that the Comma Power is required to provide power to the Comma 3 while the vehicle is switched off. However, the TPMS controller is physically located very close to the ADAS computer behind the glovebox (most Leaf users actually mount the wiring harness adapter onto the body of the TPMS controller), and it does have constant 12v supplied to it (Ref 2).

We have also confirmed that the Comma 3 is able to successfully fingerprint the vehicle without the CANbus lines provided by the Comma power. If there is a desire to phase out the Comma Power in the future, it should be possible to just add a second set of connectors to the wiring harness adapter in order to get constant fused 12v power from the TPMS controller. This would require less effort for users to install compared to the current solution which involves feeding the ethernet cable through the middle of the dashboard to reach the OBD-2 port on the drivers side.