Engine light on & gas cap fault - 2005 Buick LaCrosse

next time take it to a accredited professional shop that will read the fault codes first before advising you on what has to be replaced and not just guessing the problem

I have no idea why any parts were installed

You always check for codes & use them to
diagnose the system with the fault

You may need a professional scan tool along on a road
test to look at data as well as get caught up on some
maintenance

The information below was complied by me, it explains what causes the check engine light to come on and the process of finding the cause.
When the Check Engine light (or Service Engine Soon or small picture of an engine) is turned on, the systems computer control unit (called the PCM) has sensed a fault in the electronic controls of the engine and/or the emission system. When this happens you will seldom feel the car engine run any different. There are about 200 possible system faults (the gas cap is just one of them) that turn the Check Engine light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen/Oriley and Autozone parts stores (USA only) do this testing for free. I caution you on accepting any advice on what the problem is from a parts counter person, they are not trained and could cost you allot of hard earned money. Once you have the fault code post it here and I or another expert will take a look at the possiable casues.

CHECK GAS CAP COULD BE LOOSE OR MISSING OR LEAKING CAUSING EVAP LEAK IN WHICH WILL CAUSE CHECK ENGINE LIGHT FLASH ON..

p0496 is evap emission is high purge flow fault, p0442 is emission control system( small leak) the meaning is about the same. check for a bad gas cap first. sometimes this will set a check engine light. loosen cap and see if this is the problem. if it is. usually if you turn cap only a little the light will go out. but if bad enough just change cap.

The check engine light comes only when the computer control unit (called the PCM) senses a fault in the electronic controls of the engine and/or the emission system, there are about 200 possible faults (the gas cap is just one) that turn the light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen and Autozone parts stores do this testing for free.

Take it to a local autoparts store and ask them to read the engine fault codes. Fault codes will help determine where the problem is. Reading fault codes is usually a free service.

Also make sure that your gas cap is tight as a loose gas cap can cause the check engine light to be turned on.

Please report here as to what fault codes you have and what problems you are having with the operation of your vehicle.

Thanks

Bob

A loose gas cap will set the check engine light.Make sure the cap is tight,get the codes read if this is not the case.

when this light comes on it is to alert you to the fact that a fualt or faults has occured in the electronic engine or emission control systems, there are over 200 such faults poss that turn this light on, a loose gas cap is just one of those 100's of faults, u need to have the system tested to see what code is stored in the memory of the on board computer known as the PCM

Your evap system is detecting a small leak. the seal of your gas cap is at fault. Make sure you hear the cliicking of the cap when re-installed. If it still makes your light come on, replace the fuel cap.