Make sure you've purchased all of the required parts before beginning.
The OBD-II cable before beginning

If you plan to use an enclosure, slide the round grommet onto the bare wire end of the cable (you won't be able to do this later without cutting a slit in the grommet). If you don't use the grommet, plan on finding another form of strain relief. Cut a section of 3/8" shrink tubing about 1" long and slide it onto the cable.

The grommet and shrink tubing on the OBD-II breakout cable.

Crimp a female pin onto the following wires and verify the connection to the expected pin on the OBD-II connector using a multimeter. The pinout for the cable recommended above is available at

The CAN1, CAN2-1, CAN2-2 and 12v power wires before crimping

Take note that the crimp pins need to be squeezed in two places (ideally with a proper crimp tool) - once around the wire end, and once around the insulation.

Position the wire on the pin to get electrical connectivity as well as strain relief.

These instructions describe how to make a 3 bus cable. The chipKIT only has 2 CAN controllers, so you will be using at most 2 of the buses at one time. Most vehicles use what we will call the CAN1 and CAN2-1 buses.

OBD-II breakout cable with crimped wires
Wire ColorOBD-II PinBusPolarity
White and black 6 CAN1 +
Green and black 14 CAN1 -
Orange 3 CAN2-1 +
Purple 11 CAN2-1 -
Light blue 1 CAN2-2 +
Green 8 CAN2-2 -

When all pins are attached, verify that you have good electrical conductivity with the intended pin.

Testing crimped OBD-II pins

After connecting and testing the crimp pins, trim the red (battery voltage) and black (ground) wires down to the insulation but leave them sticking out of the main cable insulation. If you want to power the chipKIT from the vehicle in the future, you'll need these wires.

Trim all of the other uncrimped wires down to the main cable insulation - we won't be needing them.

Once you've built the OBD-II cable, attach the crimp housings.