Automotive on-board computers, do much more than control the engine functions. Known as the ECM, engine control module, in most vehicles the engine is the main focus for the ECM. In the early days of automotive computerization, engine functions were  all of the on-board computer duties, literally.

Modern cars have sophisticated computer systems, some cars even have more than one on-board computer, in that case their may be a computer to keep an eye on other functions.

As I have preached in the past, regardless of what type of problem your car may exhibit, a scan tool must be hooked up to the OBD-1 or OBD-2 DLC to determine what the problem is. Other than a good old fashioned visual inspection, in essence, you are spitting into the wind by approaching an automotive problem, or engine problem in particular without a scanner in hand.

Unless the car was so old that computerization was not an issue, the first thing I laid my hands on when going to diagnose a customers car was my trusty Snap On scanner, or “Red Cube”.

FYI: The engine light will come on for many more reasons than an engine problem. Considering the entire car is computerized, the engine light may come on if you have a transmission problem or one of the other computers or inputs to the computer/s is questionable. Questionable problems will turn an engine light on also.
An example of a computer function, when you set the A/C to become cold, lets say 75 degrees on the dash, a sensor that measures temperature will tell the computer to slow down or stop the air conditioner when the internal temperature reaches 75 degrees. Once the internal temperature rises 2 degrees the sensor sends a signal to the computer to turn the A/C on and bring the internal temperature back down to 75 degrees. A comfort control system if you will.

Much like your home, it won’t let the car become to cold or to hot inside, which of course is a great feature. It may even be considered a safety feature since you need not take your eyes off the road to stay comfortable inside your automobile.

Some of the more sophisticated cars use multiple on-board computers to handle many operations, from how well the suspension compensates for bumps and turns in the road, for your comfort and safety.

We can see how much computerization has improved the overall function of cars and trucks. Surprisingly, even the giant semi trucks we see on the highway are highly computerized.

With that in mind what is the best avenue to take when it has been determined you need an ECM?  I’m not a fan of buying a computer or ECM from the dealer. Most of the time a computer from the dealer cost an arm and a leg, plus, since it is new, it is nor programmed yet. In effect we can say it is stupid. what I mean is that in most cases the computer you purchase from the dealer for an outrageous price also needs to be programmed. That’s right, another $75 to $100, or what ever the fee is to program the ignorant computer you just payed to much for.

People take un-programmed computers home unknowingly, and install them only to find out that you need to take the computer back to the dealer  and pay for the programming. Oh, they needs the car too, and that is a tow bill you can add to the total price. Along with the irritation and frustration.

As a shop owner we made a bunch of customers glow with happiness. We knew that our engine supplier would sell us a programmed computer for about $100. Right out of a car that has been identified with the vehicle identification number VIN, to have the exact same functions as the car in question. One can save from a few hundred dollars to as much as a thousand dollars shopping wisely as in this case.

The really nice part of all of this is that the warranty is usually one year on a low mileage used ECM, which may be longer than the dealers warranty, and it bolts in, making the car use-able again, without towing it to the dealer to get it programmed.

Sounds good eh? Keep this information in mind when you need an engine repair or engine replacement. We talk about diagnostics all the time on our GotEngines.com Blog, since diagnosis is the most important function your mechanic will perform, much like a doctor will diagnose you before he decides you need surgery.

Cars and humans, yes, it is true that there is a common metric between the two. Both pieces of equipment have many separate systems that require strict diagnostic procedures before work is started. Both have to have all systems operating properly to make the entire system work correctly in whole.

Before you buy any old computer, give a call to the engine supplier who outperforms them all, @ 1-877-268-0664. Satisfaction guaranteed.