[Ovmsdev] OVMS ODBII Cable

Sun Nov 11 13:36:08 HKT 2012

OK, so I think the pinouts we require are as per Michael B's diagram:

J1962-M		DB9-F		Signal
4		3		Chassis/Power GND
6		7		CAN-H
14		2		CAN-L
16		9		+12V Vehicle Power

A right angle J1962-M plug and about 1metre cable should be ok.

This one cable should support both Twizy and Volt/Ampera, and also any ODBII car with an ODBII compliant CAN bus.

Does that sound ok?

I'll ask around in China to see if I can find someone to make these up cheaply, and get them on Fasttech.

Regards, Mark.

On 11 Nov, 2012, at 7:50 AM, Michael Balzer <dexter at expeedo.de> wrote:

> For the record: I now have connected GND to both 4+5 on the OBD2 plug, works as well.
> 
> Regards,
> Michael
> 
> 
> Am 10.11.2012 19:57, schrieb mikeljo at me.com:
>> Hi,
>> 
>> i use this pinout:
>> Primary Data Link Connector- (DLC) X84 *Under drivers side of IP
>> 
>> Pin 1 is Low Speed GMLAN (SWCAN ~33.3kbps) - Body Electrical Services Only Pin 2-3 Unused
>> Pin 4 chassis ground (for scan tool)
>> Pin 5 data reference ground
>> 
>> Pins 6(+) & 14 (-) High Speed GMLAN- Primary Powertrain Bus (DWCAN ~500 kbps) Pins 7-11 Unused
>> Pins 12(+) & 13(-) High Speed GMLAN- Chassis Expansion Bus (DWCAN ~500 kbps) Pin 15 Unused
>> 
>> Pin 16 B+ (for scan tool power) 
>> 
>> OBDII
>>             Sub-D Signal
>> 16 9 +12V
>> 4 6+3 GND-Chassis
>> 6 7 CAN_H
>> 14 2 CAN_L
>> 
>> I connect 6 and 3 at the Sub-D side together.
>> So it looks like we can use the same Cable (for the Primary Can Bus in the Volt). >> Fasttech?
>> 
>> Bye
>> Michael
>> 
>> 
>> 
>> Am 10.11.2012 um 06:47 schrieb Mark Webb-Johnson <mark at webb-johnson.net>:
>> 
>>> Yes, chassis GND vs signal GND, but can is differential, so no GND needed for the signal. We only need GND for 12V power. For vehicles, I think chassis GND is ok.
>>> 
>>> I think Volt bus we are using is on the same pins:
>>> 
>>> http://www.evtools.info/ChevyVoltOBD2CAN.html
>>> 
>>> Maybe 1 cable can do both?
>>> 
>>> Regards, Mark
>>> 
>>> On 10 Nov, 2012, at 12:18 PM, Michael Balzer <dexter at expeedo.de> wrote:
>>> 
>>>> Mark,
>>>> 
>>>> yes, that's chassis ground -- shouldn't it be? I interpreted the OVMS GND as the ground for the supply voltage (12V), as the CAN bus has its dedicated "low" line.
>>>> 
>>>> I just looked up some OBD2 sites: 4+5 normally are the same. One page says an OBD2 cable should have identical potential on 4 and 5 to ensure proper function. Another OBD2 cable I bought connects them, so maybe for a general product GND should connect both, but I don't think there's a difference on the car side... normally.
>>>> 
>>>> But I've also seen some info on non standard OBD2 plugs, also for some GM and Opel cars, having other signals where the CAN bus should be, so I'm also interested in your pinout, Michael J.
>>>> 
>>>> Regards,
>>>> Michael
>>>> 
>>>> 
>>>> Am 10.11.2012 04:23, schrieb Mark Webb-Johnson:
>>>>> Michael,
>>>>> 
>>>>> One question: you have GND on pin #4 (odb). I have that shown as chassis ground, not signal ground. Is that correct?
>>>>> 
>>>>> Michael J: is that the same connector and pins as you are using for the Volt?
>>>>> 
>>>>> Regards, Mark
>>>>> 
>>>>> On 10 Nov, 2012, at 2:16 AM, Michael Balzer <dexter at expeedo.de> wrote:
>>>>> 
>>>>>> Mark,
>>>>>> 
>>>>>> great to hear about user activity :-)
>>>>>> 
>>>>>> 1) I just created an OVMS to OBD2 cable image and checked it in:
>>>>>> https://github.com/dexterbg/Open-Vehicle-Monitoring-System/commit/a7c3a3e8f12d7759b896bb75c8e570ebc10ec11a
>>>>>> As OBD2 is standard incl. CAN pinout, this should be valid for any OBD2 port, so could be added to the FastTech OVMS product line. It's not a standard cable, or at least none I know of.
>>>>>> 
>>>>>> 2) No known way up to now. I also think the Twizy would not respond to the port, as the whole CAN bus is quiet when the car is off and not charging. Plus, because the charger draws some 30-35 W for many hours after charging has completed, many drivers use auto-power-off sockets.
>>>>>> 
>>>>>> 3) I'll forward your specification to the german Twizy forum.
>>>>>> 
>>>>>> Regards,
>>>>>> Michael
>>>>>> 
>>>>>> 
>>>>>> Am 09.11.2012 15:23, schrieb Mark Webb-Johnson:
>>>>>>> 
>>>>>>> Twizy support seems to be coming along nicely, thanks to the amazing work Michael is doing. Some good functionality there already.
>>>>>>> 
>>>>>>> I'm starting to see some Twizy users register on openvehicles.com. Perhaps the word is getting out?
>>>>>>> 
>>>>>>> Some questions / requests:
>>>>>>> 
>>>>>>> Michael: Can you let me have the details on the cable pinouts and parts you are using at the moment? Is it a standard cable, or are you having to make something up?
>>>>>>> 
>>>>>>> How is charge control on the Twizy done? Is there any way of stopping or starting (topup) a charge from within the car, or is it just controlled by plugging? Any chance of can bus control of this?
>>>>>>> 
>>>>>>> Can anyone help with the car images for the Twizy? There are lots of nice images available, but they need to be photoshopped to the right dimensions and transparent background png.
>>>>>>> 
>>>>>>> Regards, Mark.
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> _______________________________________________
>>>>>>> OvmsDev mailing list
>>>>>>> OvmsDev at lists.teslaclub.hk
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>>>>>> 
>>>>>> -- 
>>>>>> Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
>>>>>> Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
>>>>>> <dexter.vcf>
>>>>>> _______________________________________________
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>>>>>> http://lists.teslaclub.hk/mailman/listinfo/ovmsdev
>>>>> 
>>>>> 
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>>>> 
>>>> -- 
>>>> Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
>>>> Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
>>>> <dexter.vcf>
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>> 
>> 
>> 
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> 
> -- 
> Michael Balzer * Paradestr. 8 * D-42107 Wuppertal
> Fon 0202 / 272 2201 * Handy 0176 / 206 989 26
> <dexter.vcf>_______________________________________________
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