ODB-II Splitter

brandname2007 · 10-19-2007, 04:10 PM

I was curious if anybody has ever heard of, ran across, or know where i can buy an ODB-II Splitter. My intentions are to split the signal from the OBD-II under dash recepticle, to hook up to a car PC capable adapter, and still be able to use a TripSense module as well. I would be willing to fabricate one as neccessary if I know where to find the actually housing.

brandname2007 · 10-19-2007, 04:15 PM

I am looking for the J1962 female jack to 2 - J1962 male jacks, for those who are not sure what type of connector OBD-II is!

joeyoravec · 10-19-2007, 04:28 PM

They're available for sale. We sell a really fancy OBD-II breakout/splitter box. It's not cheap but it has banana jacks so you can probe every signal on the connector with your multimeter or oscilloscpe. I've seen other places sell less-expensive ones that are a simple cable.

But I would caution you that each device has a network address to communicate, including the scantool. You can't just plug in two tools like you describe and expect them to work perfectly -- they will conflict if they use the same address. Usually when people use a splitters they're "sniffing" the network to reverse engineer the network messages. In that situation they're passively monitoring the traffic and there would be no address conflict.

brandname2007 · 10-19-2007, 04:33 PM

i see what your saying... that might be a problem. but in any case, it would probably be easier to make the cable anyways, seeing that my carpc will most likely be located in the trunk, and i have obd-ii diagnostics planned for the pc. this way i can plug it in with a trunk mounted jack. then i could just unplug the pc for using tripsense for a while.

joeyoravec · 10-19-2007, 05:38 PM

Be careful extending your OBD-II. Your success all depends on twisted pair wires, shielding, and the quality of the signal. A quick search says 5 meters maximum, but I wouldn't go more than 3 meters in general. It would be better to have the tool close to the OBD and extend the connection to the PC.

It's the network that runs your motor. You really don't want hookup a long cable or a crappy tool that corrupts data on the network. Cars are unreliable enough in the first place!

Caelric · 10-19-2007, 05:45 PM

www.obd2cables.com has this cable but I tried it, and ran into the problems mentioned above. If I had two devices connected at once, only one of them would work. You might have better luck.

Dave

brandname2007 · 12-16-2007, 04:05 PM

Yeah... further investigation doesnt seem to be in my favor. My PC is a trunk mount, and I want to eventually hook up ODB, but I also have a TripSense module on it. I guess I will have to abandone either of the two... oh well. Thanks for your help guys.

Lukeyson · 01-06-2008, 04:02 AM

That OBD2Cables splitter works perfectly. I use it all the time on CAN and ISO9141.

It's dead set easy to sniff traffic from another tool. I've sent messages with an ELM, Joey's Mongoose ISO/CAN, an IDS, a WDS and an FMP (Last 3 are Ford Dealer Tools) and have been able to sniff messages on CAN with 100% success, and ISO with a fraction less success, both with either the ELM327 or Mongoose. The ISO issues have less to do with addressing and more to do with Ford not conforming to ISO perfectly.

For ELM sniffing just using Hyperterm and a mix of filters (mainly to limit broadcast traffic on CAN) and the atma command works just fine.

For J2534 sniffing you might be able to use the Drewtech software tool (I struggled with it but didn't spend that much time on it) or alternatively go for another tool I use quite a lot called IPSecMsgMon - it's a part of the Cardix SDK - and it's helped me do a range of things, and is just about the most useful reverse engineering J2534 tool I've come across.

Lukeyson

intravino · 01-20-2008, 11:21 PM

These guys have this splitter cable also:

http://www.carplugs.com/Product_list_Cables_1.html