(Video) What’s the difference between an ECM, TCM, and PCM?

1 min read

Did you know that your vehicle’s brain consists of more than just the ECM?It’s made up of a variety of things including an ECM or ECU, TCM, and a PCM. Have you ever heard of these acronyms? They can be a bit confusing if you aren’t familiar with the terms. So what are they exactly and what’s the difference?

Engine Control Module or Unit (ECM or ECU)

Let’s start with the engine control module or ECM or ECU depending on the manufacturer. Both refer to the same component so they are interchangeable. They both process information from various sensors in your car’s engine, which allows your engine to operate with optimal power and efficiency.

Transmission Control Module (TCM)

So we know what an ECM does, but what is a TCM? A TCM is a transmission control module which does exactly what it sounds like: it controls anything going on in your transmission. A TCM collects information from all sensors and determines when your transmission should shift gears. Traditional manual transmissions don’t need a TCM because drivers shift gears themselves, but most electronic automatic transmissions need a TCM. Most later TCMs will also use information transmitted over the CANBUS from the ECM.

Powertrain Control Module (PCM)

Now let’s move on to the final piece which is the PCM. A PCM is a powertrain control module, which is basically the ECM and TCM combined into a single module. It may look like a single unit from the outside, but a PCM actually has two separate units (the ECM and TCM) housed together. These units can also control other functions in a car besides just the engine and transmission.

In Search of Good Automotive Core

Now you know the difference between an ECM, TCM, and a PCM. Here at DieselCore, we’re always looking for good ECM core or any other core so visit our website at DieselCore.com for the latest buy sheet.


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