My Nissan Leaf Forum

So I haven't messed with the canbus much, but I think this might be possible (though probably quite difficult...) - The question seems unrelated at first, but bear with me


So I've been working on my audio system, with the hope/intent to stick with the factory head because of all the integration.

It's driving me nuts though The factory head drives into clipping at different points in the volume range at different frequencies, and dropping below the point where any clipping is in effect leads to an unacceptable range of adjustment steps (if amps adjusted to be good volume, each remaining volume bump is a huge change). Not to mention there are countless systems out there in the aftermarket with *SERIOUSLY* better interfaces.

So I started making a checklist of what would be lost by replacing the factory unit with an aftermarket. First, things that probably would not be lost:

- Audio: Aftermarket will replace no problem (much better)
- Nav: Aftermarket will replace no problem (probably better interface)
- Handsfree: Aftermarket will replace no problem
- Steering wheel controls: Aftermarket interfaces with nissan steering controls- unconfirmed it will work with the leaf, but proably ok
- backup camera: need to dig into the service manual, but 90% chance video is encoded in standard composite format, meaning could interface with aftermarket no problem

What *would* be lost:
-body control settings (auto lights, lock behavior, etc)
-power consumption (live kw consumed/regen'd, climate control, other)
-temperature output from climate control (just the numeric temp output)
-Charging timer controls


So here's my question - just from fiddling with things, it really seems like the stereo doesn't store or control those functions - (for example, locks, climate, and charge timers work fine in pre-selected mode with stereo disconnected; the stero is only needed to 'change' the settings)

So my thought is, if the unit is just an interface to change settings in the ECU/BCU, it's probably passing and reading these settings over the CANbus, right?

if so, would it not be possible to take the concept of the soc meter, and expand it to include output of all these settings as well? And possibly add a couple buttons and a UI to make it also capable of actually changing these settings?

Why not just set the factory system at the highest setting before any clipping occurs and then use an amp with a remote gain control ? My old Phoenix Gold M100 had one, just a remote pot and small cable. You'd then have a traditional volume control, easy to mount somewhere. No steering wheel control for volume though.

Steering controls are one reason - another is choosing between an unsightly extra knob sticking out of the dash or giving up the ergonomics of the console - another is the factory radio's general low output quality even when you do get below clipping - etc.etc... Both my amp and processor currently have remote gain adjustment options, but for the reasons above I fund that solution unsatisfactory. And even if I did like it, I still don't get around the lack of UI quality...

Suffice to say I huge amount of effort (and no small amount of money) into trying to integrate with the factory audio system, and it is simply not acceptable to me. Frankly, at this point, I might be willing to give up adjustment of charging timers (they're set like I like them now anyway) or body settings (ditto) to get reasonable sound.

Shouldn't be too hard to suss out. Hook up Gary's logging device to the correct CAN bus, and log messages while changing each of the settings. The hardest part will be creating a unit with a big enough touchscreen to do a decent job, and finding a good way to mount it.

Now what would be **REALLY** awesome would be something like an android app for control installed on a double-din touchscreen android device, interfaced to canbus via an adaptor to usb... Not possible yet since I don't think android distributions have usb host support yet, but it's been talked about as coming...

Anyway, in the short term I don't think it would have to be touch screen - something like a 20x2 text lcd display with a button-driven menu would do the job for most stuff (other than power display, which it could do, but only numeric and not large enough to use while driving)

A wired connection would be a little annoying, plus using wireless would let you do things from outside the car. You could use Bluetooth (might be annoying if you want to use BT for audio), or WiFi. BTW, I always thought it was extremely short sighted that we couldn't change most of these setting through the owner's website.Very short term, I'd say. Most of the menus aren't too bad, but I wouldn't want to have to change my charge timers very often with that interface. Plus I use the energy screen a LOT and would want the solution to display the data in a way I could easily read while driving.

The integration of the "Audio/Nav/Control/Status" functions make meaningful replacement of the "Nav/Audio" seem very difficult to do.

Start my making a detailed list of all the LEAF-specific functions on every control and every screen. General categories are:

1. Charging Station Locations ...
2. Energy usage ...
3. Backup turn radius ...
4. Carwings functions ...
5. GPS-derived data that the LEAF might use to work properly ...

Are you announcing that you are going to do some detailed analysis of the messages on the AV-CAN bus?

If not, "How do I replace the Nav/Audio unit?" probably does not even belong in the "Leaf CANbus" subforum.

The sound quality is going to also be limited by source content and the D/A converter in the unit for digital files and it seems to be somewhat poor. If you use a CD it seems better than hi-res MP3 or FLAC. Since the CD is easy to navigate as it is limited in length then the interface is not an issue. One potential way to avoid the onboard amps is to go straight to the low level by going into the unit (soldering) and then RCA out to your amps. I have already replaced my speakers with some JL separates but I need to put the JL amp on in the described manner.

I'm not announcing I'm going to do anything, I'm opening discussion about whether I'm on the right track that this information would be communicated via canbus. Perhaps that could eventually lead to detailed analysis of messaging. the question of "how do I replace the nav/audio unit" is integrally tied to the can bus messaging, what the car can and cannot function without, what functions have potential negative impacts, and how to work around those impatcts. If you feel discussion of whether something is handled via can bus messaging should go elsewhere, please feel free to suggest

As you can see in the body of the initial post of this discussion, the list you've suggested is started - thank you for the additional suggestions ( I hadn't included charging station locations, and the overlay of backup turn radius I failed to mention). That's also a good ppoint, that the car could potentially use GPS data for other functions, though I'm not sure what...

I may just have to try disconnecting the unit entirely for a period of time and documenting what is missing, first to be certain that other vehicle functions are not impacted, and second to ensure I haven't forgotten some functionality.

It would seem to me going from what the SOC meter is now, which is only listening to the busses to taking over functions that require you to generate your own bus messages is a very big step, with lots of associated risks.

In principle, it would be nice to have a GPS that generated an altitude profile for an intended route and used this to calculate a more accurate SOC for your destination. However, the GPS data base has no reason to store altitude data now, and I see no reason why there would be any bus traffic related to the GPS. It would seem that this enhancement, like better audio, would best be done completely separate from the present built-in components.