View Full Version : DIY: a 05+ VSS/Transmission in an 02-04 Car

07-15-2008, 09:26 PM
I know I know, there are a lot of DIY's written already on the switching tranny case,drilling/tapping for the 02-04 sensor, and gear swap. Those are proven to work, but ultimately the labor, tools, and knowledge required tend to steer people away from these great low milage transmissions. I have been running an 06+ Si transmission in my car (WITH a working speedometer) without having swapped cases (You need to swap shifter arms, but thats an entirely different procedure..)

Best of all, the parts for the rewiring cost me under 80 bucks. This writeup assumes you have a perfectly working harness with complete speed sensor input (IE you have a working 02-04 Sensor Plug on your engine harness, or at least the wires that lead into it)

Here is the key:

How does it work?
-Simply put, the Dakota Digital box is placed "between" your 05+ Speed Sensor and the Ecu. It reads the input signal and converts it to a matching signal that your ECU and speed can recognize.

-A working 05+ Speed sensor and
-Dakota -Digital Universal Speedometer Signal Interface (http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm)
-A soldering gun
-Electrical Solder
-Electrical Wire
-Electrical Tape
-A friend with another car

1) Wire Prep

First off you will want to run some wires and cut them to an estimated length. Run enough wire to go from your speed sensor, through your firewall, and then to your ECU. Be generous, but don't go too crazy. Do this with 2 wires. Run one into the input spot, and the other into the output 4 spot on the box.

Now youll want to cut the power and ground wires. I placed my converter right next to my ECU, so I needed under 1 foot of wire for the power source. I used one of the ECU mounting bolt threads for the ground. Its not the BEST ground source, but it works. Both wires ended up under being under 1 foot long.

2) Splicing/Soldering

Here is a pinout for the wire we are going to splice. This is one of the harnesses on the ECU.


We want to splice into Wire 1 for the power source.

You will want to remove the tape around the wires are expose them. Just take an x-acto knife, box cutter, or razor and take your time. Once the wire is exposed then solder the end of the power wire to #1 and use the electrical tape to cover your tracks.

For the Ground Source, choose a metal threaded surface and run a wire from the box to this surface. I chose the lower right ECU mounting thread.

Now for the Sensor Wiring. Here is a paint diagram lol.

Splice the Input wire into the wires labeled input. This should go from your dakota box to the wire on your old transmission's VSS.

Splice the Output wire into the wire labeled output. This should go from your dakota box to the wire on your new transmission's VSS.

Solder the remaining wires from the VSS's to each other as shown. The red connection is power and the black is ground. I used an exacto knife to expose the wires and soldered accordingly. Wrap em up with electrical tape.

3) Calibration.

You wiring is now complete. Turn on your car and check for proper connections. The green led on the dakota box should be flashing with your engine on.

Set switches 1,2, and 3 to the on position, set switch 4 to off. This will get you to within 5-10 percent of the actual mileage reading.

Now get your friend and his car on the nearest highway. Pick a speed and have him set the cruise control. Now match the other car's speed and use the up and down buttons on the dakota box to set your speedo to the appropriate speed. Holding the buttons results in a much faster adjustment.

Test your calibration with another speed. Your done. Sweeeeet.

chad jones
07-16-2008, 02:23 AM
oh lawdy. I can swap over to my k20z1 tranny now!

Thanks papy

07-18-2008, 10:19 AM
good write up. and thank you for the compliment on mine...:yo:

07-18-2008, 10:47 AM
cool write up!

07-19-2008, 05:51 PM
Very nice write up! :mcool:

07-19-2008, 09:49 PM
Nice info! Very helpful.

08-30-2008, 11:31 PM
This is exactly what I used. I does take a bit to get cal'd right.