2003 Mitsubishi Lancer Evolution VIII

ECU Removal

• Tools you'll need

  • 10mm socket wrench

  • Flat head screwdriver

  • work light (I recommend a fluorescent bulb in a work light - it's much cooler and won't burn you)

  • Adjustable pliers

• Removal time: 15 mins (taking your time)

• WARNING!!!! - To prevent INJURY or POSSIBLE DEATH, please disconnect the battery BEFORE beginning this process.  You will be working within proximity to the passenger airbag, so in order to prevent accidental deployment of the airbag, disconnect the battery to kill the power to the airbags.

• Disconnect the battery - (10mm nut) This is really a no-brainer.  If you want to keep your brain, then disconnect the power to the airbag unit which you'll be working in front of.  Last thing you need is to somehow set off the airbag while working around its wiring harness.  Simply tilt the red cap upwards, exposing the 10mm nut on the POSITIVE terminal.  Loosen, and then move the wiring from the positive terminal and sit it on the battery bracket - that way it keeps it safely away from the terminal and prevents it from making contact to the terminal.

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• Remove the glove box door - (left side stopper) Pretty simple to do, but does require some know-how in order to remove the stopper without breaking it off.  Open the glove box door, and then tilt the glove box door almost the entire way out.  On the back left corner of the glove box, you'll see (or feel) a stopper tab on the outside.  Simply place your left index finger over the stopper, and your thumb over the part of the stopper on the inside of the glove box, and then pull forwards, towards you.  It should simply unsnap from its mounting, and then you can thread it thru the hole in the glove box and remove it.  With the left stopper removed, flex the glove box towards the left to help the right stopper tab clear the dash opening.  Once the right stopper is cleared, fold the glove box door towards the floor, and the hinges will eventually allow you to lift the box out.

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• Remove the wiring harness interior trim plate - Locate the trim plate that sits below the glove box  (See pic below). The picture is taken from the passenger foot well, and the item to the left in the background is the center console.  There are four tabs that hold the trim plate in place - two in front, and two at the rear of the trim plate.  Take notice of how they are lined up before removing the trim plate.  To remove the trim plate, simply grip the plate at the back edge near the rear tabs, and pull straight out towards the passenger seat.  It will require moderate force, but it'll just pop off.

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• Remove three 10mm bolts from the ECU bracket -  Once the glove box is removed, you'll see the ECU bracket exposed, attached to the passenger side dashboard supports.  Remove the three 10mm bolts holding that bracket in place (see red circled bolt heads in picture below).  Be careful of the ECU and don't let it fall down to the floor.  Gently guide the ECU and bracket to the passenger foot well.  Note the cabin air filter installed to the right of the ECU bracket (the white plastic rectangle).

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• Rest the ECU on the passenger floor - See pic below.

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• Remove four wire harness plugs from the ECU - Using adjustable pliers, carefully remove each of the four plugs from the ECU by gripping the plug by the tab on the plastic base and then squeezing the tab with the pliers, and then pull it out.  The plugs all seem to be unique sizes, so it shouldn't be difficult figuring out which plug goes where when reinstalling the ECU.

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• Remove the metal bracket from the ECU - Once the ECU is free from the wiring, you can remove the bracket from the plastic ECU box by using a flat head screwdriver to wedge between the box side and the bracket.  Gently bend the metal bracket out to clear the flat tab on the plastice ECU housing side.  Do this on both sides of the housing.  Once both sides of the bracket are bent out to clear the tabs, use the screwdriver once again on the top of the ECU housing to gently pry the brackets out of the guides on each side of the housing.  Move each side just a bit each time in order to keep the motion pretty even between each side.  When you reinstall the bracket on the ECU housing, simply bend the metal bracket back in on each side so that the plastic tabs will engage the bracket.

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• Mail your ECU  to your favorite tuning shop for a reflash.

© 2004 EJEvo Enterprises, A division of EJHonda Enterprises.  All Rights Reserved.