#WHAT IS A ECM ON A CAR SOFTWARE#
These EPROMs were a step up, but the erasing of the software on the EPROM required that it be removed from the ECM and placed under an intense ultraviolet light source, then reprogrammed using a special programming system. With newer technology came the EPROM, or erasable programmable read-only memory.
#WHAT IS A ECM ON A CAR INSTALL#
If you wanted a different calibration or an update to address a TSB, you were forced to buy a new PROM and install it in the ECM. After the PROM was programmed with a certain calibration, that was it – you couldn’t change the software anymore. The older PROMs were only programmable once. The software calibration within the PROM provides the proper “tuning” for the engine. These engines may be similar in architecture (like the Camaro 5.0L HO and Corvette 5.7L TPI, both V8s) but different in specification (different camshaft lift/duration, different EGR valves/ports, different fuel injector sizes and flow rates, etc.), or the engines may be of different architecture, like the four-cylinder in the 2.5L S-10. By changing the PROM, we can make the same computer properly control different engines. To clarify this a little further, let’s take a look at the software structure within the ECM. The PROM contains the calibration software for the ECM. The only difference (aside from the vehicle wiring harness pin population) was the PROM. This ECM was used on the 1989 S-10 truck with the 2.5L four cylinder, the ’89 Camaro with the 5.0L HO V8 and the ’89 Corvette with the 5.7L Tuned-Port V8 engine. For example, in 1989, Chevrolet used one engine control module, P/N 1227165, to control three different engines. The PROM chip is used to calibrate the ECM so that it is configured to run a particular engine. Naturally, this short list does not describe the entire contents of the ECM, but what is important to our understanding of flashing is the PROM part of the ECM. They have a microprocessor, built-in random access memory (RAM), signal-conditioning chips (for sensor inputs), output transistor/drivers (for actuating ignition coils and fuel injectors) and a programmable read-only memory-type chip (PROM) for calibration purposes. Going back to the basics, you know that all automotive engine and powertrain control modules (PCMs) are essentially small-sized, dedicated computers. Before we get into what it takes to flash ECMs, let’s take a closer look at what flashing really is, why it is utilized on virtually all late-model cars and why this is such a great opportunity for repair shops. In case you’re on the technological slow boat, “flashing” refers to reprogramming automotive engine control modules (ECMs). I think we can all agree that the first group is far better off, and the only thing we need to expose is the benefits of this new “flashing” technology.