Using OBDLink SX to Log the LEAF's CAN buses

The OBDLink SX device was built to be an interface to almost any
OBD2 in most fairly recent cars. In cars with a "standard" CAN bus,

It can be initialized to just Read the Messages that it sees on the bus.

It is fairly inexpensive ($50 now), and connects to a PC via a USB connection.
There is a version with BlueTooth, but it is more expensive, and it is not clear
that the data rate is sufficiently high to Log a busy CAN bus.

It is sold by ScanTool, and also available via Amazon.

The LEAF has a "car" CAN bus, and two others on its OBD port.
The iMiEV, in comparison, has only the "car" CAN bus, but it is
a rather busy bus, with perhaps 1600 messages per second.

Some folks are using this device with the RealTerm program in
the PC to gather information from the "car" bus and write Log files.

I modified CAN-Do to read these RealTerm Log files, and I have now
programmed CAN-Do to accept data directly from the OBDLink device.

More later.

Inside the OBDLink SX device, the pcb is hardwired to the
OBD connector, so modifying the device to read the EV bus
instead of the CAR CAN bus is not trivial, but not impossible.

It appears that two connector leads (to CAR-CAN) could be cut,
and two jumpers (to the EV-CAN OBD pins) could be added.
It is just not obvious which leads to cut.
An ohm-meter and some investigation would be likely to provide
the answers, since OBD pins 6 and 14 are the CAR-CAN bus.

Possibly a miniature slide switch could be added to choose
between the EV CAN and the CAR CAN buses.

I successfully logged the LEAF's CAR-CAN bus using the
ScanTool OBDLink SX device today, using my v196 of
CAN-Do.

I used 500,000 baud after a series of "AT" commands
to setup the OBDLink to output all the CAN Messages
in a MMMD1D2D3D4D5D6D7D8<LF> format, receiving
over 1000 messages per second.

I verified that the Accelerator Pedal Position value
was found in the expected message.

It seemed to work quite well, but the LEAF was only in
AUX-2 mode, not READY, and not actually driving.

I still need to automate the OBDLink setup process.

Also, I have ordered 2 more OBDLink SX units,
and I think I will modify one to read the EV-CAN bus
Then, with an OBD "Y" cable, I will be able to read
both the EV bus and the CAR bus at the same time.

Of course, I will need to modify CAN-Do to read the
EV bus from the OBDLink device, like it reads the
CAR bus now.

I have this cable, so I'm quite interested in using it for EV CAN bus logging. To read it, would I have to do anything else but switching pins on output?

Welcome to LoggoLand.

I suggest that you first try using your OBDLink device with
CAN-Do v196 or later to capture the CAR-CAN bus data.

Get the program here:
http://www.wwwsite.com/puzzles/socmeter/CAN-Do-v196.zip" onclick="window.open(this.href);return false;

Then, after you know that you are able to get it setup
properly, capture and save the data to log files, and
have learned how to use Recipe files and plot data,
we can open the OBDLink SX and determine which two
connections to cut and reconnect to the EV-CAN bus
on the OBD connector.

I will post the pin numbers in this thread, soon.

You should be able to see and graph the Accelerator
Pedal Position from the CAR-CAN data.

By that time, I am likely to have CAN-Do modified to
accept the OBDLink format of input on the EV-Comm
input channel.

The LEAF OBD (called Data Link Connector by Nissan) Pin Numbers:
Please verify before use, but I believe these are correct.

5 is Ground, and 4 is Shield
16 is 12v battery, and 8 is switched 12v

6 and 14 are CAR-CAN, high and low
13 and 12 are EV-CAN, high and low
11 and 3 are AV-CAN, high and low

In "normal" late-model cars, which usually have a CAR-CAN bus,
the OBD pins 6 (high) and 14 (low) are specified by Standards, so
the OBDLink SX (and other similar devices) use these two pins to
support their CAN bus connection to the car.

The LEAF uses 13 (high) and 12 (low) for its EV-CAN bus, but I do
not know what, if anything, might be attached to those pins in
a "normal" (possibly older) car, and thus used in the OBDLink,
that was designed to be able to read almost anything from
most "normal" cars.

So, even though we know which pins to disconnect in the
OBDLink SX, we should first check that the pins we want
to use are not connected to anything else.

When I get some time, I will look at my OBDLink SX
more carefully. If you are compelled to open yours,
there are only 4 screws, and you might report what you
find, so we can verify each other's conclusions about
the best way to make this "EV" modification.

If there is sufficient room to mount a 2-pole 3-position
mini slide switch, I might try to connect to the AV bus also.

It looks like this would require unsoldering plug and reconnecting it with a switch - maybe it would be easier to buy socket and plug and then connect them externally creating universal switcher. It is pretty late here now, but I will give a try tomorrow to connect to car and read something from car CAN bus.

Use at your own risk, but this is what I think I found:

The OBDLink SX has an 8-pin right-angle connector
that is soldered between the main board and the
OBD connector breakout board. Pin 1 has a square
solder pad, and is closest to the OBD pin 1 and 9.

The connector pins (as it appears to me):
1. Goes to OBD pin 2, function unknown
2. Goes to OBD pin 10, function unknown
3. Ground, from OBD pins 4 and 5
4. (x) is CAN-H, from OBD pin 6, CAR-CAN High
5. (x) is CAN-L, from OBD pin 14, CAR-CAN Low
6. Goes to OBD pin 7, probably for the K-line
7. Goes to OBD pin 15, function unknown
8. Goes to OBD pin 16, for 12 volt power from the car

Mod for EV or AV:
1. Cut two traces on the OBD connector breakout board,
near OBD pin 6 (going to right-angle connector pin 4)
and near OBD pin 14 (going to right-angle connector pin 5).
See the two (x) above.

Mod for EV:
2. Connect OBD pin 13 (EV-H) to right-angle connector pin 4 (CAN-H)
3. Connect OBD pin 12 (EV-L) to right-angle connector pin 5 (CAN-L)

Mod for AV:
2. Connect OBD pin 11 (AV-H) to right-angle connector pin 4 (CAN-H)
3. Connect OBD pin 3 (AV-L) to right-angle connector pin 5 (CAN-L)

If installing a slide switch, I would probably wire EV, CAR, and AV from
the OBD connector to the three slide switch positions, with the two
right-angle connections to the two common switch pins.
Take care to get all the High signal wires on one pole of the switch,
and all the Low signal wires on the other pole.

I got CAN-Do programmed to accept the OBDLink SX data
format on the EV input channel, but I have not yet been able
to test it. I have captured OBDLink input from the CAR-CAN bus.

I ordered some 3-position, 2-pole slide switches, which should
fit into the OBDLink SX shell. Then, I will modify the OBDLink SX
to be able to select the EV, the CAR, or the AV CAN bus.

I have no soldering skills and devices :-( I will connect tonight and see if I can receive any data.

CAN-Do Update:

This version should now read the EV CAN bus in OBDLink format,
but has not yet been tested, because my OBDLink SX device
has not yet been modified to read the EV bus instead of the
CAR-CAN bus.
.
A previous version was tested with readig the LEAF's CAR-CAN
bus with the OBDLink SX device, and it appeared that it got
all the CAN Messages.

The bug with reading ".alc" log files and using the Dashboard
to display variables ... has been stomped out.

http://www.wwwsite.com/puzzles/cando/CAN-Do-v198.zip" onclick="window.open(this.href);return false;

is the updated program.
Enjoy, and any suggestions are welcome.

I am testing logging both EV and CAR CAN buses today, with two
OBDLink SX devices, one slightly modified to connect to the LEAF's
EV-CAN bus instead of the CAR-CAN bus.

To try to capture all the CAN Messages, I will set both devices
to operate at 500000 baud, up from their default of 115kbps.
Each device connects to a different USB port on the PC, and both
connect to an OBD "Y" cable that I purchased.

First, I will try just logging the EV data, then the CAR-CAN data
and finally logging both simultaneously.

I already discovered one bug, the EV-Comm Setup function used
the Comm Port assigned to the CAR-Comm channel.
So, I am now testing with v206 of CAN-Do, to be available later
today.

Found a 2nd bug in v205, so I will try to get the next version on Sunday.

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Product Description


Acurar Professional Tool H685


Function: 

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Systems supported: 

H-onda/Acura Professional Tool H685 can support the following systems:

PGM_FI

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The appearance of a H685 is as shown in the above figure.
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5). LEFT/RIGHT arrows: move cursor.
6). Power button
7). Diagnostic extension cable: OBDII -16PIN / HONDA 3PIN

Rod,
Is this device useful on the LEAF in some way?

WARNING:
I carefully opened the OBDLink SX and cut the two
traces on the OBD connector breakout board that
go to the connector to the OBDLink board.

I wired the pins used by the EV bus to the same
connector, where the CAR-CAN had been connected.

I plugged the USB connection into my laptop, with
no connection to the OBD connector, and the PC
recognized the OBDLink SX as usual. Good, I thought.

I unplugged the USB connection, and tried it again
about 5 minutes later, and now the laptop complains
that the USB device is unrecognizable.

So, now I appear to be stuck.
Thus, I warn you that this device MIGHT be fragile.

My slide switches, 3-position, 2-pole, arrived yesterday, but
now I am hesitant to open and modify a second OBDLink SX.

More thought, perhaps...

I ordered on eBay something like this product:
http://www.amazon.com/OBDII-Splitter-J1962M-2-J1962F-145802/dp/B000TMCX72" onclick="window.open(this.href);return false;

I could then avoid making changes to USB cable, just rewire one socket for EV CAN and I guess some time in future other one for AV CAN, this way I might be able to access all CANs using OBDLink - does this makes sense?