To be absolutely sure, you should:
* Check your owner's manual: This is the best source for the precise location.
* Look for a label: Sometimes there's a label indicating the ECM location on a component nearby, such as the fuse box.
* Consult a wiring diagram: A wiring diagram for your specific year, make, and model will pinpoint the ECM. You can usually find these online through repair manuals or parts websites.
If you can't locate it after checking these resources, a local mechanic or auto parts store should be able to help.