How to Remove the ECU in Vehicles

by Contributing Writer; Updated June 12, 2017

The electronic control unit (ECU) is responsible Vehicles managing numerous aspects of a car's performance. When the unit is in need of service or replacement, it must be located, disconnected and removed from the Vehicles. If you want to install an aftermarket performance chip, you will have to remove the ECU. On a Vehicles the ECU is located behind the glove box, so it can be serviced with relative ease and some basic hand tools.

Under The Hood:

 How to Remove the ECU in a Lexus SC400

Disconnect the negative battery cable from the battery with a socket and ratchet.

Remove the fasteners that secure the passenger kick panel with a screwdriver. The kick panel is located on the right side of the lower dash between the dash and the floor.

Pull the kick panel away from the vehicle to expose the silver ECU.

Unplug the wiring harness from the ECU. There is a lock on each end of the harness. Pull up on the tab on each end to unlock the harness.

Remove the bolts that secure the ECU to the vehicle with a socket and ratchet.

Secure the new ECU onto the vehicle with the bolts, socket and ratchet.

Plug the wiring harness into the new ECU and push down on the locking tabs on both sides of the harness to lock it into place.

Secure the kick panel into place with the fasteners and screwdriver.

Reconnect the negative battery cable with the socket and ratchet.

Items you will need

  • Socket and ratchet set

  • Screwdriver

 How to Remove the ECU on a Ford Focus

Pop the hood of your Ford Focus to access the engine compartment. Use a wrench to loosen the nut on the negative battery terminal then pull the cable completely off of the terminal.

Open the glove box and remove all of its contents. Apply firm pressure to the plastic sides of the box, pressing toward the center until the plastic guide arm is free of its groove. Continue pulling the door open. The pressure will allow it to swing beyond its usual tilting point. Several electronic devices will now be exposed. The ECU is a metal box with a white sticker displaying a four-digit code.

Unplug the wiring harness from the hookup on the back of the ECU. Use a 10 mm socket to disconnect the bracket holding the ECU in place and pull the unit out of the glove box area. It can now be serviced or replaced as necessary. Simply reverse the above steps to reinstall the ECU.

Items you will need

  • Wrench

  • 10 mm socket

 How to Remove an ECU From a Lexus

Move the passenger side seat all the way rearward using the power seat controls or the manual adjustment bar (depending on the Lexus model). This provides more room to work.

Disconnect the black (negative) battery cable using a wrench, and then lift the cable from the battery post to isolate it. This prevents an electrical short while you are removing the ECU.

Locate the panel attached to the front edge of the center console on the left side of the passenger foot well. You need to remove this panel to access under-dash components such as the ECU.

Remove the screws or bolts from the panel. If you do not see any, the panel may attach with plastic clips. In this case, use a plastic trim tool to gently pry off the panel. Move it aside to access the ECU.

Locate the ECU. It is a metal box about the size of a microwave dinner, and is usually silver or bronze color.

Unplug the two electrical harnesses attached to the ECU, and remove its mounting bolts or screws. There are usually four bolts, located at the corners. Lift the ECU out.

Items you will need

  • Wrench

  • Phillips screwdriver

  • Socket wrench

  • Plastic trim tool

About the Author

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