Gas Cap vs Chk Eng Lite

If the smog tester ran the engine while the gas cap was not installed, this can cause the Check light. The Evaporative Emissions Control includes a check that the gas tank is sealed. If the seal is broken, the Check Light can come on.

The vehicle uses OBD II (On Board Diagnostics, Level II). This is a standard that all venicles built from 1996 and on will use. You can often times check the tool out from the auto parts store and pull the codes yourself. It takes less than 5 minutes, and you can easily do it in the parking lot of the store. The tool will also reset all codes.

If you need that second mortgage, give me a shout - I'm a mortgage lender.

Bill's link gives all of the codes that are possible, but not all cars can generate all of the codes.

If there is a code, and all cars generate it, it will mean the same thing all of the time. But if there is a code that a car can't make, then it simply can't make it.

I noticed an error in the list. P0439 Catalyst Heater Control Circuit (Bank 2)

P0439 Evaporative Emission Control System

Notice that these two symptoms both use the same code, I think this is an error. The Evaporative EmissionControl System fault is P0440. This code means the evaporative system isn't sealed, which happens when the gas cap is left off, and other faults can be triggered as well. These subsequent faults can either dial the fault in to a particular part, or can simply be a reaction to the open system. My strategy would be to make a list of the codes, then reset them and wait to see if the light comes back on again once the gas cap has been put on correctly, or replaced if defective.

One can also search the web for "OBD II CODES" and come up with a variety of hits that give the varous codes and some even list up the diagnostic scanners that can pull the codes. The diagnostic tools are available in a range of prices, the more expensive units have additional features.

lol, funny how people make a mountain out of a mole hill, hahaha. I had my check engine light come on about a month ago and thanks to already hearing (last year?) about the on,off,on,off,on trick (from Bill) I pulled the codes on my odometer. Bad news is the code told me my tranny was destroyed but that's ok.

Go to Auto Zone they will use a scan tool for free and can reset the check engine light for you too. The largest cause of the check engine light is the gas cap, most of the time it will be a P0454 or P0455 a leak in the emissions control system. Buy a new cap that Auto Zone it makes them feel good after using the scan tool.

Maybe you should go on the Jay Leno show.

Dave Lee did pass the time by typing:

Yes and yes.

There are three basic types of codes. Ones that set but don't display (non critical), ones that set but can be cleared, and ones that set that require the DRB to clear.

Can't remember what DC calls them. micanic would know.

I have a small leak in my down pipe after hitting a rock, When im stuck in the traffic for too long the sensor will detect the small leak and will give me check engine and then the GC is running terrible. I disconnect the battery for 10 Sec and tada the light dissapear. The code might stay log in the computer but it's running ok and not worse or better on gas then before.

Pat

"DougW" a écrit dans le message de news: uUpZd.11484$ju.9519@okepread07...

Actually, I like your link. It has an error on P0439 & P0440, but this is nothing in the grand scheme of things.

Whether pulling the codes by swithcing the ignition off and on, or by usingthe code reader tool, the error remains the same, and the rest is beside the point, I suppose.

Because in the past 6 weeks the Check light came on on my daughter's truck, and the code was P0440. There were other codes as well, but they all related to an open in the fuel system somewhere. She said that she found the gas cap not fitted properly, and this can contribute to the other codes we got. We got three codes in total, but I only remember the P0440 without looking at the choices.

All I was pointing out was that the link you posted, just by chance, lists two P0439 codes, but the second of them should be P0440. P0440 simply means the Evaporative Control System is open. Check another ODB II Code List to confirm. And, the second digit is 0 (zero) not O (uppercase o).

Actually, no, it is a Toyota Truck. But the OBDII information on this site,

says that all vehicles use mostly thesame codes. So, if a vehicle makes a P0440, then all vehicles that make thecode have the same problem and all vehicles that have the problem make thesame code. There are some codes that are manufacturer specific, and I amignoring these for the moment. Having said that, I notice several descrepancies in the link I posted and the one you posted so I must not fully understand all that I think I know.

All I was saying is that in the link you posted, there is a code, P0439 that says two different things. The second thing it says is really code P0440. I am sure this is nothing more than a typo on the part of whomever created the list, and the proofreaders were simply dizzy from all of the data that looks nearly identical from one line to the next.

And, it turns out my daughter's gas cap tossed up a 440, 441, and 446 if anybody cares.

I just got a 0442 on my 01' WJ and it was the darned gas cap. $10.95 later from the dealer and my problem was fixed :)