LEAF CANbus decoding. (Open discussion)

[JeremyW]

Not exactly CAN related, but related to the "eyebrow" temperature readout I found today in the service manual:

The A/C auto amp. internally processes the ambient temperature data is two data types: data for A/C control
and data for ambient temperature display.
The A/C auto amp. inputs the temperature detected with the ambient sensor as the ambient temperature.
When the vehicle speed is 30 km/h or less, if the effects of radiator heat and other factors result in a sudden increase in detected ambient temperature, the A/C auto amp. performs delay correction so that the recognized temperature rises slowly. Correction is performed so that the change is recognized quickly when the ambient temperature drops.

Also interior:

In order to prevent effects from uneven temperatures inside the vehicle and from external disruptions, the A/C auto amp. performs correction so that the recognized interior air temperature changes slowly. The A/C auto amp. performs the correction so that the recognized interior temperature changes according to the difference between the detected interior temperature and the recognized interior temperature. If the difference is large, the changes occur quickly, and becomes slower as the difference becomes smaller.

[JeremyW]

54C byte 5 appears to be climate control fan voltage at 0.05 V/bit. Fan speed is proportional to voltage and there's a handy chart in HAC, Pg 19 that I'm not about to copy here. 4.0-12.5 Volts

54C byte 0 is evaporator temp (we've known that for a while), but I'm not sure of the scale... I think it's 0.1 or 0.2 C/bit.

54F byte 0 appears to track interior temperature, but I can't figure out scale or offset.

[JeremyW]

Here's a big one: available power

We found msg 260 on car CAN contained available power/regen to the "bubbles" display in the instrument cluster. Well now I think I found where *part* of the message is originating from on the EV CAN bus. Thanks to Turbo3 for isolating a LBC module, we know that msg 1DC is from the LBC along with 0x1DB, 0x55B, 0x59E, 0x5BC, 0x5C0 (although I've never seen msg 59E in my logs??).

I've plotted 1DC byte 0 (red) and 260 byte 0 (blue) on the graph below from TickTock's last 16 gids to turtle run:

car260ev1dc.png

Note there are some points at the end where 260 returns to "full" but this is just a characteristic of what happens after the contactor opens (all the bubbles come back).
There's some points where something else is limiting maximum power. Perhaps climate control or something else? Normally 1DC byte 0 is 0x6E or 110 kW. Msg 260's highest is 0x5A (94kW). Lowest observed during TT's run was 0x31 or 51 kW. There might be other messages that control output when you are down that low BUT I also note that the 1DC value is low (0x65 or 101 kW) at 16 GIDs.

I encourage others who have logs of say 100 gids to turtle (or even VLBW) to examine message 1DC to see where the BMS starts limiting output current (byte 0 going below 6E).

I also think the available charge power is also on this message but I need to look through some more charging logs. I'm about 95% sure it's on byte 2 but that byte does kinda weird things during drive. On the consult tool there are separate fields for "available regen power" and "available charge power".

[TickTock]

Hmmm. Try plotting 1D5:D1[7:5]-D0 (Applied Regen). Since available regen is reduced when you apply traction power, maybe available power is reduced when you apply regen.

[garygid]

Has anybody found a Stop-Charging message yet?

Set up to do logging of the EV-CAN bus from the OBD connector.
During charging, use Carwings to Stop charging, and try to find
a CAN message that stops the charging process.

Similarly, while doing the J1772 charging, press the button
to unlock the J1772 plug-handle, and again see if there is
a Stop-Charging message.

Once identified, if it exists, it is likely that I could modify the GID-Meter
to have a stop-charging function, which the user could set
at almost any SOC level. Anything over 95% would probably
be a normal full charge.

Or, it is likely that Leaf Spy Pro could be have that function added.

[TickTock]

Has anybody found a Stop-Charging message yet?

No. And several of us have made concerted efforts to find one (We have been trying to implement the feature you describe for some time). See this most recent (and most promising) post from Jim and followon analysis by Jeremy.

Does CarWings have an option to stop charge? I didn't think it did.

[JeremyW]

CarWings does not have a stop charging message. As far as I can tell, the command from the telematics (EV bus message 56E) is pretty simple and made up of a few bit flags.

Code: Select all

hex   binary   state
86   10000110   idle
46   01000110   status
4E   01001110   cc on
56   01010110   cc off
66   01100110   remote charge


From the highest bit: idle, VCM wake-up logic line status, remote charge, cc off, cc on, unknown, unknown, 0. The unknowns could be 12v supply voltage voltage ok and "within cell coverage"

Since that time I've never seen anything other than these states. You could unplug the TCU and try sending some other things like 0x67: 01100111 and see if that turns it off. However, I doubt Nissan would have left this functionality on the table. The only thing that I think they might have left on the table is the code to change the remote turn on temperature. In the 2013+ models this is a command from the AV unit to the climate control computer. I haven't isolated the message on a 2013 but I suspect it *might* work on a 2011 or 2012.

You might look at EV bus message 1F2. I suspect commanded charge power is in here.

[JeremyW]

Similarly, while doing the J1772 charging, press the button to unlock the J1772 plug-handle, and again see if there is a Stop-Charging message.

At least in the 2011-2012 models, proximity is handled by the onboard charger itself. It will report that it has gone to 0 current (and it might change another bit indicating proximity has changed) but the rest of the leafs systems will continue to run (pumps, DC/DC, etc) until the cord is pulled out. As far as I can tell, under all conditions, the VCM (master computer) is the "conductor of the orchestra" and has the final say as to what state the car is in. You will probably have to send a request to the VCM to stop charging.

[JeremyW]

Not sure if this is true for 2013+ leafs, but it appears that msg 380 shows a few QC parameters.

Byte 0: 02 drive, 12 L1/L2, 82 start qc, 83 end qc (82/83 might have bit flags for the qc contactors), 86 qc

Byte 1: 04 not qc, 84 qc in progress

Byte 2: 10 drive, 13 qc, 22 end qc, 18 L1/L2

Byte 3 is QC Voltage

Byte 4 is QC commanded amperage

Not sure the scale for bytes 4/5.

Byte 7 looks like mains (AC) voltage is on here?

[JeremyW]

Message 1DA looks like it has the individual phase currents of the motor... or the current through each IGBT. Byte 6 has 4 mux channels (0-3) with the MSB of that byte indicating negative (2's complement) or positive with byte 7 being the data. The data looks periodic in nature, but I haven't had a chance to really study it.