Remapping an ECU & ECU Flashing

Okay for those of you who are interested in ECU remapping and reflashing this is a simple guide to give you some insight.

Your engine ECU (I refer to the 'engine' ECU because modern cars can have various ECUs for other elements such as brakes etc) is basically a computer which controls the running of your engine. It contains various stored data which it refers to when doing this. There are various reasons why you may want to reprogram this software such as the software becoming corrupt, a new updated version being available which deals with previous bugs or to improve/change performance.

When it comes to changing the performance this is called 'remapping'. Put simply, where in the past engineers would have physically altered settings to tune up an engine they are now doing it electronically. Primarily, settings for fuel, ignition timing, turbo boost (if fitted) and rev limits are altered.

In many cases engines have plenty of scope for an improvement in performance without physical upgrades. Many different vehicles from the same manufacturer will have the same engine but some may be de-tuned simply to comply with tax brackets, insurance groups or local laws on emissions

In other cases remapping may have to be accompanied with an upgrade in the vehicle's brakes, exhausts, cooling etc. as the standard equipment fitted may not be able to cope with the additional stresses.

How is remapping achieved?

The normal process is to read the current software in your vehicle and save it as a file. Then use specialist software to open that file and alter the settings within it as required and again save it. This file is then programmed back into the vehicle's ECU. It is sometimes also referred to as ECU flashing or re-flashing.

That's the basic process but don't assume that you're going to be able to do this all in 5 minutes.

How to read and write ECUs?

Most modern vehicles' ECUs can be read and flashed via the diagnostic socket (either under the bonnet or inside the vehicle). While manufacturers and their dealers may have equipment to do this, it isn't available to the general public. In come third parties who have created their own equipment which is made available to pretty much anyone. Depending on the vehicle and ECU Flashing equipment you have you may be able it read/write via the diagnostic socket, by plugging in directly to the ECU on a bench or by physically connecting to a chip within the ECU.

Manufacturers are well aware that third parties are altering software within their ECUs and continue to make their systems more complicated and 'hack' proof.

Click Here to see a Peugeot 306 HDi ECU being read and remapped.