Check engine light turned on, then off?
The "check engine" light can go on for lots of reasons. The most common are related to the oxygen mixture with fuel not being right. This can be caused by a faulty gas cap, use of low-octane gas and several other things. I add higher octane gas and the check engine light goes away after a couple of days. In your case, the light went off - so whatever sensor was sensing some sort of issue, that issue is now gone...
After a week, my Check Engine light went off...?
About a week ago, my check engine light came on (2003 Hyundai Elantra with 93000 miles). I took it and had the code read at a Valvoline (and to get my oil changed), and it was an oxygen sensor that was slow to respond. I couldn't have it fixed right away, so I was going to call my mechanic in a few days to get an appointment to get it fixed. Anyway, after three more days, I started my car to go home from work, and the light was out. It hasn't come back on since. I thought this was a good thing. From what I've read online, and what my father has told me, it will go out after a while if the problem isn't detected any more...and after a certain number of starts or miles or soemthing... I have two questions: Is this really okay that the light went out (a friend of mine said it could be a bad thing...so I'm not sure)? And, should I still take it to be looked at, or can I wait and see if it comes back on again? Thanks! :)
My check engine light went off after I went over a bump?
It may be that the light just happened to turn itself off at that time. Some codes will reset themselves based on various things like hours, miles, and starts. A flashing check engine light usually means that the problem is serious and or happening at all the time. A steady light usually means the problem is no longer happening or its a more minor problem. It may have just been time for it to reset itself because the problem was no longer happening and enough time, miles, or starts had passed. If the dealer is willing to still look at it and maybe help with the repair I would still bring it to them. The code will still be stored in the system so they will be able to check it and see what it was even if its not still a problem. Temp sensors are usually not that expensive and are easy to test.
Check engine light went off by itself. Still get it checked?
As you stated a loose gas cap can set a light, on some cars once it's tightened up it will clear itself and turn off the light, but normally that takes about 50 restarts without a failure when the system checks for pressure build. For peace of mind have it checked. It could be something totally different and is giving you an indication of something starting to act up.
What does it mean if my check engine light goes on and off?
The computer is constantly testing all of the sensors amidst it's preset standards that are expected.Sometimes those parameters are violated which will cause the engine computer to set a check engine code and light on the dash.If it is minor enough or intermittent it is possible to go through enough testing cycles where it doesn't see the issue again so it will actually clear the code(usually leaving it in history) and turning the check engine light back off.If it is a current constant happening - blinking on and off - over and over again over just a few minutes or less, that is usually not a good sign as the computer is detecting a major issue related to the running condition or emissions related issue that should be looked at immediately to prevent possible damage to related components.
Car engine check light was on and then off the next day, is that a good thing?
One of the most common causes of the check engine light is an improperly installed fuel cap. Since a sealed fuel system is important for emissions control, the PCM will detect when the pressure in the tank is wrong and turn on the light.Put the cap on properly and the light will go out after a couple of stop/start cycles.You can go to almost any auto parts store and have them plug in a scan tool and pull the recent trouble codes. This is usually a free service.
The check engine light went out after I put octane boost in, is the problem fixed?
The octane boost had absolutely nothing to do with your CEL going out.Sufficiently tightening your gas cap did.Yes, if the gas cap is not snugged down ...like when you put it on make sure you get two or three "clicks" out of it ...if the cap is too loose you will trigger a CEL having to do with a fault in the evaporative emissions system.I might question the addition of "octane boost" in your car. If your car is designed to run on regular grade unleaded fuel then there is no advantage to either using premium fuel or octane boost; that would be a waste of money.If your car has an engine management computer capable of detecting increased octane fuel then you will get some benefit from upping the octane. How much? Try it with and without and see.
My car's check engine light went off...the computer pulled out the diagnostic code p1502. What is this?
P1502 Radiator Fan Function Problem if they told you that you needed your timing belt changed, then they are trying to take you for money, don't go back to them. get the fan looked at. is the temperature getting to high when you are moving ? like on the freeway ? if its fine when your moving, then the fan is the only thing that could be broken.