Honda ecu location

Location of most Honda Civic/CRX ECUs

Most of the time, it is in the location pictured below. This is true for Civic models, while Accord models have it at the bottom of the center console. Some models use an ECM (or ECU) for the engine and one for the automatic transmission (TCM or TCU), while other models use one module for both (PCM).

You located the module but aren’t sure whether it is the engine ECM. You can confirm by checking the part number on the box. It should be in the format of “37820-Pxx-xxx,” and you will find that number on its side label. The “X” in the number format can be any combination of numbers or letters. Any number that doesn’t start with “37820” is not the engine ECM, but a different module, since there are several electronic modules around the interior of the car.

In the picture below, you can see an example of a P04 engine ECM. The complete number is “37820-P04-G52”. You can notice that every time we refer to an ECM as the “P04“, “P28“, “P0A“, etc., we are referring to the three characters in the middle of the complete ECM part number, as it is the code of the ECM “family”, while the last three numbers are the country, transmission, and software version. In this same example, the “G52”, “G” indicates that is a European ECM from Great Britain of GDM (Great Britain Domestic Market), The “5” means automatic transmission (5 and greater = A/T, while “0” is M/T) and the last number, the “2” is and identifies of the version of the software (there are “0”, “1”, “2” and in some, “3”).