How much does a replacement or reprogrammed ‘plug and play’ ECU / ECM cost?

Note: A high quality vin matched replacement ECU / ECU is typically $600 less than dealer installed parts.

Reflashing: How to Flash or Remap an Engine Computer Unit (ECU)


Reflashing an ECM is a tuning technique that is also often called flashing, remapping, or flash tuning. Like any computer, your car’s ECM has software with different settings or parameters, and these can be changed to alter the performance and driving limits of a vehicle. Reflashing or remapping an engine computer is essentially just the process of replacing the existing software in a vehicle controller with new software.

Reflashing an ECM is an immensely powerful technique that allows the engine to be tuned in the same way that the factory calibration engineers perform the task.

What Is an ECM?

As we’ve explained before in past articles, your car’s ECM is its central computer. It controls, monitors, and regulates all of your engine function to ensure your vehicle is running at its optimal performance level. What makes engine computers especially advanced is the fact that, not only are they tailored to your specific vehicle, they are also able to learn about you, your driving habits, and the conditions you typically drive in.

Essentially, the ECM adapts cars to their drivers, in order to ensure those drivers are getting the most out of them in the most efficient way.

ECM Parameters

The real brains behind your engine control module is its software. Essentially, the software determines the limits within which the engine is allowed to operate. These original parameters are at least in part determined by what the manufacturer expects you to get out of the vehicle and the level of performance that they think you expect to get out of it.

Engine parameters may include fuel injection volume, throttle-fuel volume mapping, gear shift mapping, and so forth. Because these limits are tailored to your specific vehicle and engine, you can’t just swap out one ECM for another without also updating or modifying the software. This is where remapping an ECM comes in.

Why Do I Need an ECM Reflash?

As we mentioned, when manufacturers build a new vehicle, they program the engine module to certain set specifications. However, in many cases, these settings may not be the most optimal ones possible for your vehicle or for what you are looking to get out of your car performance-wise.

This is because ECUs are programmed with built in safeguards designed to cover the use of substandard or lower octane fuel, to meet environmental regulation standards, and to protect the engine from the damaging effects of neglect – like leaving it too long between services. Essentially, an ECM reflash is either done to improve the performance (or make it more to your liking) or to match an aftermarket ECM with its new vehicle.

  • Remapping an ECM for Economy – For business owners who have a fleet of commercial vehicles, fuel efficiency is the name of the game. Flash tuning an ECM can help you decrease your fuel costs by optimizing your engines for fuel economy.
  • Reflashing for Performance – A performance reflash can help you maximize the drivability and responsiveness of your vehicle, as well as allow you to get the most power possible out of your engine.
  • Flashing because of Vehicle Issues – If your vehicle is showing false error codes, has a hot or cold starting issue, experiences idle roughness, stalling, or an emissions failure, it may be because the existing software needs to be replaced.
  • Flash Tuning for a Different Vehicle – This type of reflash is performed when an aftermarket ECM is installed in a vehicle. For people who just want the latest OEM software, flashing their new aftermarket engine computer can give it the same parameters and settings they had with their previous factory engine computer.

Remapping an ECM for a Different Vehicle

At Car Computer Exchange, we remap and reflash repaired engine control modules in order for them to work seamlessly with vehicles they weren’t specifically designed for. Reflashing allows the engine to be tuned calibrated in the same way that the factory does it. In other words, flashing an ECM allows it to have the same software and parameters that it would have were it in a vehicle rolling new off the assembly line.

Without reflashing, the data stream from an aftermarket computer that the other components in the car rely on will be missing or not meant for your specific vehicle. Because the ECM is so important to the proper function of nearly every vehicle component, this might mean that the rest of your vehicle will suffer performance problems or that it won’t operate correctly.

The advantage of this process is that you can use a different engine computer than the one your vehicle originally came with. That new ECM can be remapped to operate with your specific engine, and use the available maps and the way the way your old ECM operated to be very accurately tailored to the requirements of your engine.


Reflashing and remapping an ECM is what both allows you to make your engine and vehicle more to your liking, and allows software for different vehicles to be added to different engine computers. At Car Computer Exchange, we remap computers to do just that. Allow you to get a repaired and refurbished ECM with OEM software from nearly any manufacturer.