engine check light?

Question

when would an engine check light turn on? what has to have happened for it to sent a signal to the computer for it to turn on? and if its not on a luxury car, it wont turn on just as a reminder for regular maintenance, so what could it be for?

Answer 1

there are about 400-800 differnt reason that light could be coming on. so i cant give you a definitive answer. some are simple and easy to repair like a gas cap left loose but some are not.
HOW THEY WORK the car is constantly checking the sensor data its recieving and there a set amount that values should fall between. if these values are not within that range
the computer sets a red flag up.
also there is what is called a class two data stream that the
different computers or modules communicate together on, and if one is not talking to the others, so to speak, it will also
set a flag.
there are also differnt classifications of codes, some do not
illuminate the MIL. these days it doesnt have to be a luxury car to have a oil change light on.

Answer 2

Check engine lights are usually for emission related problems,there to many sensors to list all of them.Also on some cars the check engine light will come on if it gets a transmission control module request,TCM's do not have there own light so the TCM will send a signal to the PCM to turn the light on.When the vehicle is scanned it will usually say if it is PCM related or TCM related.
You need to take to a shop that can scan your vehicle and hopefully tell you what it needs without ripping you off,you can always ask another question if you get a code number we might be able to give you a definition for it

Answer 3

The only way to find out why the light is on is to hook it up to a scanner which can read the chip holding the codes. The codes tell the service people where the most likely source of the problem is. I take my car into the local auto parts store. They have a scanner which can read many vehicle codes. The scanner is hooked up to a plug which is usually under the dash on the drivers side. Many auto parts chains provide this as a free service. I took it to AutoZone. Hope this helps.

Answer 4

actually a check engine light can come of for hundreds of differant reasons. What you need to do is go have some diagnostics ran on it. Most cars have a way to hook it up to a little monitor that will flash so many times at you to tell you what is wrong with the car. MOST CARS!!! if you have an Advanced auto or and auto zone i believe that they do free diagnostics but there are many reasons that light can come one and depending on what kind of car it is it might come on for regular maintenance if you don't have a maintenance light somewhere. hope this helped some

Answer 5

Check engine lights alot of the time come on because of emissions, so it is probably air flow for the EGR, which is something that doesnt really hurt performance, so you dont really notice a difference in driveability when the check engine light has illuminated.

Answer 6

There is a malfunction in the engine or some component. Like your O2 sensor or some other sensor not reading correct. good luck and have it checked out at Autozone or some other shop.

Answer 7

Check your gas cap, or have it taken in to have the code cleared. Alot of times these lights mean nothing. What type of car are we talking about? How many miles?