I'm not an expert, not a professional, just a guy who did these steps and it worked... if you follow these steps, hopefully it works for you too. If it doesn't, I'm not responsible for whatever happens - the harness doesn't work, you fry the ECU somehow, you open a portal to another dimension and alien unicorns conquer our planet... stuff like that. You're doing this at your own risk!
Tools: Wire strippers/cutters Needle-nose pliers Molex crimping tool (not required) Soldering iron (recommended, not necessarily required)
For the parts, if you have the spare wire sitting around, you can save a few bucks and buy just the female OBD-II connector and just run the 4 wires you'll need between the OBD-II and 4-pin connectors. You'll need to know what size wire you have in order to buy the proper 4-pin connector though.
Of the 16 wires on the OBD-II connector (OBD2C), only 4 are being used:
Pin 4 (Chassis ground; orange wire on OBD2C)
Pin 6 (CAN [J-2234] High; green wire on OBD2C)
Pin 14 (CAN [J-2234] Low; brown w/white stripe wire on OBD2C)
Pin 16 (Battery power; green w/white stripe wire on OBD2C)
Again, I'm not proclaiming to be a pro, if you feel the need to criticize, by all means build one yourself and write up a better DIY.
1) Based on other guides, it was recommended to twist the pairs of wires. With this in mind, I removed the sheath and shielding from the wires on the OBD2C and separated the 4 wires to be used. I zip-tied the remaining 12 wires to keep them out of the way.
2) The first problem with the parts I used is the wires in the OBD2C are 26AWG and the pins for the 4-pin connector (4PC) are sized for 22AWG so the wiring isn't quite big enough. The wires come pre-stripped with about 1/8" exposed. I stripped off more until it was about 3/8" exposed then folded it over on itself and twisted it to "thicken" the wire to better fit the pin. The 4PC kit comes with 4 rubber seals; slide one over each wire.
3) On the pins for the 4PC, there are 2 pairs of prongs (for lack of a better/proper term), one pair is folded over the exposed wire, the other pair is folded over the seal. Insert the exposed wire to line up in the front/first pair of prongs. The pic shows how small the wiring is compared to the pin connector itself. I had to use my needle-nose pliers to hold the wire in place for the next step.
4) I chose to solder the wire to the pin connector. I preferred the solid connection of the solder, plus the wire is so small I'm not sure how I could've crimped the prongs down over the wire without the solder holding it in place. My soldering skills leave a lot to be desired, but I've been doing it for various little projects on my bikes and luckily have been successful so far. Here's a YouTube video with some tips/tricks which I've found helpful. Pardon the horrible photo; I took several and this was the "best" one.
5) For this step, if you have the proper Molex crimping tool then crimp the connector over the wire.
I didn't want to spend the money on a tool I only intend to use once. Using needle-nose pliers, at an angle, squeeze on one of the prongs to start folding it over onto the wire. Repeat for the other prong. YouTube to the rescue - here's a video I used to help with how to crimp the prongs over the wire. For extra measure, I used the pliers to crush the prongs down a bit further; admittedly, it's probably overkill at this point.
6) Slide the rubber seal up so that it fits between the 2 back prongs, use the same technique as before to fold the prongs over the seal.
7) I don't claim to know why, but in the other "how-to's" I used to create the harness, I saw it recommended to pair off the wires (in specific pairs) and twist them together. Pair off the wires in the following manner:
Pin 4 (orange) / Pin 16 (green w/white stripe)
Pin 6 (green) / Pin 14 (brown w/white stripe)
Sorry... no photo of just the wires paired/twisted
8) Insert the pins into the 4PC in the following orientation (see pic below):
Pin 14 (brown w/white stripe) > connector slot A
Pin 6 (green) > connector slot B
Pin 16 (green w/white stripe) > connector slot C
Pin 4 (orange) > connector slot D
I inserted the pin through the rear of the connector and then used the needle-nose pliers to pull the pin and lock it into the connector - you'll hear an audible click once it locks into place.
Successfully tested/used to check an error (I created myself ) and clear it.
If something doesn't make sense let me know and I can try and take a photo of it or better explain.
The reason for twisting the wires is to balance them so you don’t get interference from external sources. I believe they have to have the correct number of twists over a given distance. For the purpose of this I can’t see it been a problem. Good little project.
Nice job and I have taken it one step further but only because the OBD2C lead which I purchased had an issue with pin 16 (power) and would not power up my scanner. So, because my scanner was a cheap ass eBay job which cost me around £8 a long time ago ($10.40), I decided to cut off the original OBD2 plug and just fit my Sumitomo 4 pin plug direct to my scanner. Incidentally the Sumitomo 4 pin plug sold in the UK is the Sumitomo MT090.
The only difference then was the colour codes of the wiring inside my scanner plug.
Pin 14 (brown w/white stripe) > connector slot A is now Blue Pin 6 (green) > connector slot B is now Purple Pin 16 (green w/white stripe) > connector slot C is now Yellow Pin 4 (orange) > connector slot D is now Green
I hope you are ok with my linking other Yamaha and MT10 sites to this page.