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Chip Tuning, Remapping, ECU- Glossary to Your Car Computer

Chip Tuning, Remapping, ECU: Glossary to Your Car Computer

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Looking to modify the computers in your car to get more power or efficiency? A quick Google search can be incredibly confusing. If you’re having trouble telling the different ECUs apart or comparing chip tuning vs. remapping, this quick guide can help you understand what they are.

Chip Tuning:

Early engine computers were first introduced in the 1980s and changed the way that engines were tuned up. Suddenly tune-ups were no longer about adjusting parts like a carburetor. In order to change key engine parameters, the chip had to be physically removed and replaced with a new chip. This was the original chip tuning, where the tune-up involved switching out the chip.

This term gets a little murky as technology evolved. The introduction of diagnostic ports meant chips didn’t have to be removed to be changed. The diagnostic ports allowed direct software access, so the chips could be reprogrammed without being removed. Today, chip tuning can refer to either replacing the chip completely or reprogramming the chip. But technically, it’s when the chip is removed and replaced with a customized chip.

Engine Remapping:

Remapping happens when the software in the chip is changed without changing the chip itself. The existing engine map is coded into the software of the engine’s computer. This software is then overwritten with a new engine map, or remapped.

If this sounds like modern chip tuning, that’s because many people will call it chip tuning, but technically it’s not chip tuning. A good way to remember the difference is that chip tuning involves changing the chip, while remapping involves changing the software.

Electronic Control Unit:

These are the actual computers in your car, also known simply as ECUs. The name refers to the entire unit itself, which consists of a computer board inside a casing with ports to connect it to the car. There are a wide variety of different ECUs scattered around your car, controlling things like your in-dash system, power steering, anti-lock brakes, engine, and more. Any time anything electronic is run, there’s an ECU behind it.


Here’s yet another common place for confusion. The Electronic Control Unit that controls how the engine works is know as either the Engine Control Module (ECM) or the Engine Control Unit (ECU). This is the specific computer unit that controls engine settings like the timing, fuel injectors, etc.

Powertrain Control Module:

Just to make things even more interesting, there are also Powertrain Control Modules, or PCMs. These control both the engine and the transmission settings, and are more common in cars from the 1990s to early 2000s. Modern cars, however, have a separate ECU/ECM just for the engine controls.

Performance Chip:

These are the aftermarket chips designed to replace the manufacturer’s chips or software. There are a couple different types. Control modules are permanently installed between the sensors and the ECU, while power programmers are temporarily used to change settings through a diagnostic port. Both of these are widely available options, but don’t offer the customization of a professional chip tuning or remapping.

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