Electronic Control Module Replacement

Most modern cars are like computers on wheels. In fact, all newer cars have a number of computer parts on them, in the dashboard, under the hood, and part of the mechanics of the car. One of these computers, the Electronic Control Module, often called the ECM, is the most important computer in your car. The ECM sensors in your car collect data from the sensors of other parts to ensure each part is functioning properly. Without the ECM, most cars won’t run at all. Follow the steps below to learn how to replace the ECM on your car.



Find a New ECM

You can find a replacement Electronic Control Module either online, through a dealership, or sometimes at an auto parts store. Because it is an electronic component, they aren’t always in stores. Be sure to order the exact make, model, and year of your car to get the right ECM. A new ECM is going to set you back somewhere between $100 and $400, with newer models usually being more expensive.


Get the Right Tools

There are two major tools you will need to make this repair, although it is simple. One of these is a socket wrench. Socket wrenches are used in a lot of repairs, so you should buy one for your own use if possible. The other tool isn’t much of a separate tool, but a component to the socket wrench, and that is a socket set. The sockets you will need will change depending on the sizes of bolts your car uses.


Disconnect the Battery

One of the most common first steps to any auto repair is to disconnect the battery. Luckily, if you have a socket wrench, this is easy. Open up the hood of your car and locate the black cable. You only need to disconnect this cable to prevent any accidental discharges.


Find the ECM

The ECM is found in one of two places in almost all cars. It will either be under the dashboard of the passenger seat, or in the engine compartment itself. Locate the ECM, which should look like a silver rectangle. If this is not the case, your car owner’s manual may be able to tell you where it is.


Disconnect the ECM

It is best to prevent shock before doing anything else. After you gain access to the ECM, which may involve removing some interior panels, find the electrical harness. There should be a tab that holds the connection together. Press down on this tab and pull the connection apart to disconnect it.


Free the Old ECM

When the wire is disconnected, the ECM is only held in by screws. You will need to remove these screws before you can take it out. Keep track of the screws so you don’t lose them. You will need them to install the replacement. You should use the socket wrench to loosen the screws.


Install the new ECM

After removing the old ECM, you need to position the new ECM for installment. Line the ECM up so it can be screwed in the same way the old one was. You may need to hold it in place in order to begin screwing it in. Make sure the bolts are tight by tightening them with the wrench.


Reconnect the Power

Plug the ECM back in. This is done similarly to how it was connected in the first place. Join up the two parts to the electrical harness so power can get to the new ECM. You may hear a click of the tab fitting into place.


Connect the Battery

The black cable under the hood should still be disconnected. Now is the time to reconnect it. Secure the black cord back on the terminal it had been on. You can use the socket wrench to make sure it is firmly attached.


Check the Replacement

This is the last step, which will test the connection. Close up the hood and start up the car. You should see a warning light like the check engine light if the connection is not secure. If there is a problem, check to make sure all the wires are attached correctly.

The Electronic Control Module is an important part of a modern car. It helps to manage all the electrical workings of your car. The repair may be a bit costly, but it shouldn’t take too long. As long as you know where the ECM is, you shouldn’t have to spend more than 15 minutes performing this repair.