LEAF CANbus decoding. (Open discussion)

So I got a PCAN tool to help do some decoding of the CAN buses, with emphasis on helping decode climate control and remote queries. Playing around with it today, I used TickTock's doc to help find climate related values on the car CAN bus. Here's some observations:

510 byte 4- tracks "climate control" under the energy info screen exactly (goes up and down in lock step)
50a byte 18- 1A/1B observed with AC on (too cold for full AC power), up with compressor engagement (when I hear the compressor kick on) and slowly drops down to 18 when turning off climate control. I think it is "refrigerant pressure signal detection value sent from VCM" as listed in the service manual

5a9 byte looks to be eco mode flags for climate/other reasons. I observed a change when switching back and forth between eco and drive (but remained stationary) but NOT between drive and park.
Climate on (heat):
eco 16 30 de c3 50 00 00
drv 78 14 50 0d 83 00 00
Climate off:
eco 87 18 b0 de c3 50 00
drv 86 16 80 0d 43 00 00
The first byte varied by 1 bit in a few readings though.

Remote climate/SOC:
I observed a new message header/address of 68 on the EV CAN bus that appears exactly 1 time when invoking a remote climate request. I tried sending this through PCAN View but it didn't do anything. Bummer. I suspect it is the TCU (it is on the EV bus according to the service manual) but there might be more to it...

I'm looking at trying out CAN Trace for a free 30 day trial, but it's 495€ for the full version. :shock: It does have some very nifty "database" options which can convert hex to "real world" values, and there is logging and other features... wish they made a "lite" version!

Nice find! 510:4 is something I was looking for (I want to take climate control power into consideration for my DTE just like the Leaf does).

On the 50a message above, I assume you mean byte 4. Also what is the payload for of msgId:068 for CC request?

I added msgId:510 byte:4 (5103) to my watchpoints on CANary and observed a few more details. The MSB appears to be CC on/off. When I turn off the heater, bit7 is immediately cleared but the rest of the bits drop more slowly to zero. I was watching the power into the battery (did all this while parked BTW) and confirmed that the actual power draw also tapered off with those bits so they do appear to be an indicator of climate control power. I also noted that 0C corresponded to 1.5kW and 18 to 3kW (dropped the msb). I never saw odd numbers so it appears only bits 6:1 are valid. So, shifting right, that makes 6=1.5kW and C=3kW or 0.25kW per tic.

I plan to subtract this power from the power being drawn from the battery for the purpose of computing (and recording) driving efficiency and adding it back in when displaying so the variability due to CC use will be eliminated and the driver can see the impact of turning CC on/off immediately. No big revelation, the Leaf already does this - CANary will just do it better. Nice find, Jeremy!

TickTock,
I'm fairly sure that the GIDs field in your canmsgs document is incorrect. On my MY13, I find it is at CarCAN msgID 5B3, Byte4:bit0 to Byte5:bits7-0 (Byte0 to Byte7 ordering). Your list is a great help, thanks for the effort!

like2bike said:

TickTock,
I'm fairly sure that the GIDs field in your canmsgs document is incorrect. On my MY13, I find it is at CarCAN msgID 5B3, Byte4:bit0 to Byte5:bits7-0 (Byte0 to Byte7 ordering). Your list is a great help, thanks for the effort!

Click to expand...

Quite right. Thanks! I have corrected it.

Greg has been off the grid for a few weeks but is now back. He is more than happy share his learnings:

GregH said:

Send:
792: 03 22 12 10 for ampacity
Returns
793: ?? ?? 12 10 xx xx
My code shifts this number xxxx>>4 to get an approximate amps

792: 03 22 12 30 for line voltage
Returns
793: ?? ?? 12 30 xx xx
My code shifts this number xxxx>>7 to get an approximate volts.

Click to expand...

garygid said:

Good work, my friend.
Do you have the MsgIDs that GregH uses to determine the
J1772 Pilot signal percentage or Max-Amps value?

It would be nice to see what current capacity each EVSE has
to offer.

Cheers, Gary

Click to expand...

I am so very pleased that you (several) guys are
discovering these great data-gems in the LEAF.

The first seeds of CAN investigations sown by turbo2ltr
approximately 3 years ago are really bearing fruit.
Well done, all.

Sincerely, Gary

Sadly, there is no "magic" can bus command to wake up the VCM or the rest of the leaf. The Telematics module wakes up the VCM over a dedicated logic line, according to the service manual. The command I was seeing 68C (I thought it was 68 but I wasn't looking closely enough!) seems to be the first message on the bus when starting the leaf regardless of mode (you pressing the start button or doing a remote request). The payload for 68C is 00 and appears only one time at the start.

On a lighter note, on the car can bus:
54B byte 4 is user requested fan speed
50A byte 4 is 80/A0 for off/on (respectively) of the rear defrost.

Hello everybody,

First of all, I appreciate all your work and sharing the efforts and results. After visiting this forum for a lot of times, I have registered myself a few minutes ago.
I'm sorry to smash the latest topic, but I have an urgent question.

Out of the postings before, the Identifier for "wheel speed" seems to be 284 for the front left wheel (google-doc sheet). From another sheet of the 370Z, the msgid seems to be the same.

https://docs.google.com/spreadsheet/ccc?key=0An7gtcYL2Oy0dGRaSWl6VTV2eXBQMy1ON2xZSzlMUXc#gid=1" onclick="window.open(this.href);return false;
https://docs.google.com/spreadsheet/ccc?key=0AnNSKKWgqclKdGhzNDNzUnV4bWctSHhrdjJacUhhR3c&usp=sharing#gid=0" onclick="window.open(this.href);return false;

1.) Does anybody has some experiences with these values, if they're "real"?
2.) How should I interpret the "high" and "low" byte in msgid 284?

Theoretical: If I divide the max value form high Byte [F0] through 160.934*2, i'll get in dec format 0.7954 (-> :| ). In the 370Z sheet, the result should be a value in mph.

The result must be a combination out of the low and high byte, but I don't know how.

It is a 16 bit word so you take high byte times 256 + low byte. Keep in mind the 370Z tab is from a different car so the ratio will likely be different to convert to mph (different wheel).

JeremyW said:

Sadly, there is no "magic" can bus command to wake up the VCM or the rest of the leaf. The Telematics module wakes up the VCM over a dedicated logic line, according to the service manual. The command I was seeing 68C (I thought it was 68 but I wasn't looking closely enough!) seems to be the first message on the bus when starting the leaf regardless of mode (you pressing the start button or doing a remote request). The payload for 68C is 00 and appears only one time at the start.

Click to expand...

I see a single 68C on EVcan but it isn't the first - it is the 406th message I got after pressing the "ON" button.

Keep up the good work guys, and a very
Merry Christmas season of peace and
happiness to each of you.

It has been my pleasure to work with many of
you, and I encourage you all to continue
to do good things with your lives even after
I have... am no longer able to contribute.

garygid said:

It has been my pleasure to work with many of
you, and I encourage you all to continue
to do good things with your lives even after
I have... am no longer able to contribute.

Click to expand...

Best wishes Gary and thanks for your tremendous contribution! It has been a pleasure working with you.

I spent some time last night trying to find a message indicating the number of regen bubbles to help shed some light on the regen reduction riddle. I failed to find anything that directly correlated 1:1 with regen bubbles but I think I found something better. CarCan msgId:260 d:1 appears to contain available regen. I put a watchpoint on it in my CANary for my drive this morning and saw that regen bubbles appear when this message reaches 6, 12, & 18 (I presume I would have gotten the last bubble if I was able to reach 24). There is hysteresis so the bubbles only disappear when it falls to the threshold below that (the 2nd bubble comes on with 12 and off with 6; similarly, the 3rd comes on with 18 and off with 12). Should be illuminating to plot this along with speed, SOC, and temperature throughout the last year. I hope to do that tonight.

Mucho Cool, very nice find.
Your software has matured wonderfully.
Hopefully I can get time to do an update soon.

There should be something on the EVbus from the BMS indicating max allowed current draw and max allowed regen. They're probably in the same message. Maybe look for a message that changes in turtle mode as well as being different at full SOC vs mid SOC with full regen... Do we even know exactly which messages are from each controller? If LeafSpy can clear DTCs it might be worthwhile unplugging controllers one at a time and see which messages disappear.. There may be a sanitized version of the same info echoed through the VCM for the display.

garygid said:

Mucho Cool, very nice find.
Your software has matured wonderfully.
Hopefully I can get time to do an update soon.

Click to expand...

Sweet! Glad to hear it - your earlier post sounded like you were bowing out. :?

TickTock said:

I spent some time last night trying to find a message indicating the number of regen bubbles to help shed some light on the regen reduction riddle. I failed to find anything that directly correlated 1:1 with regen bubbles but I think I found something better. CarCan msgId:260 d:1 appears to contain available regen. I put a watchpoint on it in my CANary for my drive this morning and saw that regen bubbles appear when this message reaches 6, 12, & 18 (I presume I would have gotten the last bubble if I was able to reach 24). There is hysteresis so the bubbles only disappear when it falls to the threshold below that (the 2nd bubble comes on with 12 and off with 6; similarly, the 3rd comes on with 18 and off with 12). Should be illuminating to plot this along with speed, SOC, and temperature throughout the last year. I hope to do that tonight.

Click to expand...

On the drive home I was able to confirm that, indeed, the final (4th) regen bubble lights when 260:1 reaches 24. Furthermore, I was able to get the message to go all the way to 32 - equivalent to 1 1/3 more bubbles which the dash was unable to display. Would be interesting to see how high it can go for folks living near hills (requires long durations of regen to build up the regen bubbles).