How to reset the ECU (from OG TR)

This resets the value read from the throttle position sensor into the timing advance map.

  1. Turn ignition OFF.

  2. Short blue/yellow wire terminal of the service check 2P connector and positive (+) terminal of the battery with suitable jumper wire.

  3. Turn the ignition switch to ON, check that the headlights light up.

  4. After 1 second or more passes, disconnect the jumper wire. Check that the headlights turn off (the ECM is rewriting data).

  5. Check that the headlights light up again (the ECM ended rewriting data normally).

  6. Turn switch to OFF.

  7. Serve and Enjoy.


  1. Ignition OFF. No need for a picture, just take the damn key out of the ignition and I promise you it will be in the off position…unless it’s stolen. If this is the case, no need to follow anymore instructions because you are a D-bag.

  2. Remove battery box. If you can’t do this without pictures, then stop now and take your Ruck to someone who knows how and let them finish this How-to for you

  3. Locate the P2 Service Check wire. It’s Blue with a yellow stripe and has a BRIGHT RED PLASTIC CONNECTOR on the end of it. If you were sitting on the Ruck and looked down directly between your knees, it would be right in your line of sight. Here it is:

  4. Locate the positive ( + ) side of your battery.

  5. Find a SUITABLE JUMPER WIRE = Something of similar gauge to the P2 wire that has enough length to COMFORTABLY reach BOTH the P2 terminal AND the positive side of the battery.

I used a piece of AMP turn on lead I had left over because it was of similar gauge and I wanted something brightly colored because I planned on leaving it. (I’ll explain why later) A few common wires you may have laying around that will suffice: Speaker wire, small lamp cord, anything that is of similar gauge that has a BRAIDED conductor (copper,etc.)

  1. Now that you have your “suitable jumper wire”, get ready to connect it. Don’t have any butt-connectors or alligator clips to attach the wire? No problem, just strip off approx. 1" of insulation from the jumper because you’re going to be wrapping one end around your battery screw and the other around the P2 terminal CONNECTOR. If you have connectors, good for you. I wouldn’t waste them if you don’t plan on leaving the wire connected.

Wrap one end of the exposed wire winding’s around the screw and re-tighten it. Make sure the other end IS NOT AND WILL NOT TOUCH GROUND! Give it a gentile tug to check for a stout connection. Should look like this when you’re done: (Notice the BLUE wire)

  1. Grab the P2 connector and use something small enough to release the metal terminal from the RED plastic housing. Should look like this: (Don’t worry, it WILL go back in as long as you don’t jack it up)

  2. Now wrap the other end of your wire TIGHTLY around the neck of the exposed terminal until your comfortable with the connection.

  3. Go grab your key and insert in the key hole.


Make sure the head light is visible to you. Meaning can you see the head light? Can you at least see the head light shining on some thing? if not, then make it so.

Turn the key on and wait for the head light to go out. Depending on your model year, the head light may go out and stay out for a while then come back on, it may blink off then come right back on almost instantly (don’t blink), or it may just turn off all together and not come back on 'till you turn the key off and then BACK on. I’ve heard a few different scenarios, but I can only vouch for the '08 - It blinked and came right back on.

  1. Turn the key to the ON position WHILE KEEPING AN EYE ON YOUR HEAD LIGHT(S). You should hear a solenoid “CLICK” when the headlight(s) “do-what-it-do” and the re-writing is taking place. I disconnected FROM THE P2 TERMINAL right after my light came back on, you may want to do the same. Turn OFF and remove your key when you’re done.

  2. This is where 2 paths can be taken: If you want to keep the wire, proceed to step 12.2. If not, loosen the positive terminal screw JUST ENOUGH TO BE ABLE TO PULL THE JUMPER OUT, NOT TO DISCONNECT THE BATTERY, then re-tighten said screw. Slide the P2 terminal back into it’s RED plastic clip and reassemble your battery box.


If you wanted to keep the wire:

I chose to make mine more permanent because I’m pretty sure I’ll be resetting in the future for GOD KNOWS what, but if my battery should ever die, I won’t need much more then a multi-tool to reset when replacing the battery.

12.2- Use a “dead end” butt-connector or GASP, electrical tape, to THOROUGHLY INSULATE THE EXPOSED WIRE END so that it doesn’t ground and short-out. Wrap/tuck it up with the other wires to keep it from rubbing on anything metal, just in case. Looks like this:

1 Like