2007 aspen. Recently (sometime in the last e year i think) we were getting a amber MIL indication on the instument cluster (this is what the OM calls the amber picture of an engine on the lower left section of the speedometer by the 10). Had it OBD'd, with a code referencing large emmission leak or something like that and a new gas cap was purchased and that seemed to take care of the problem.

In the last week, we get a "gascap" message on the odometer while we drive the car in addition to the amber MIL on the left of the speedometer. Just got back from Advance Auto, and they let me try a new gas cap, and that wasn't the problem. I am suspect of the sensor that is telling me that I have a bad gascap. Anybody have any suggestions about where that is, or how to troubleshoot, or have seen a similiar problem?
thanks

 

OK.....

If you have the codes pulled, You will likely find P0457....Loose or MISSING fuel cap. This IS NOT TO BE CONFUSED WITH EVAPORATIVE EMISSIONS LEAK.!!!!!!

What happens is this.....The same way that your vehicle knows there is an evap system leak, is what is going on here, The difference is that A GASCAP will NOT fix it.

When you shut the car down, A SNAPSHOT of your fuel level is posted in the computer. When You start the car , one of the self tests that is performed is "LARGE EVAP LEAK TEST" which will detect a LARGE leak in the evap system , and Light up the C/E lamp with the appropriate code.

Moving on.... If you were to go to the gas station......You shut the car off, The snapshot is posted,You add gas to the tank, and you start the car. That snapshot is compared to the new fuel level, and the car "KNOWS" he just got gas. If the LARGE LEAK SELF TEST fails, Immediately after Adding fuel, Your computer comes up with the LOGICAL scenario, that you forgot to put the Cap Back ON.....
Screwing a "TEST CAP" on the filler will do nothing until the completion of a Drive cycle. After that drive cycle is complete, one good trip turns off the c/e lamp, But NOT the warning message.
I use a scan tool to clear the message, Simply because there is one on the table next to me.....SO I'm not exactly familiar with the customer clearing procedure...Check your owners manual.

 

What have you done to fix this? I have purchased a new gas cap and nothing not fixed but the dealer tells me to drive it for like a week and see if it goes off????

 

Well golly gee whiz Gulliver......

Did you read my answer to the original post?????Complete with instructions???

 

Well I sure did! But i was asking the OP if he had fixed his problem!! But ok I see how it is gonna be on here...forget it ..sorry i asked!!

 

If you read it, You would Know exactly how to fix it.....

I do this on a daily Basis, and ,It almost always works out. The rare few that do not, Require an ESIM replacement, but it is still too early to condemn that yet.....

Your Dealer should have turned the warning off when they did the diagnosis.

A GASCAP REPLACEMENT AINT GONNA DO IT. In your owners manual there is a reset procedure, And it certainly doesnt take a week....

 

I can't believe the answers some dealers are providing for various issues. That would definitely turn me away -- and never come back.

 

Well.... In everyones defense...

Honestly, after the next Fuel stop, the light will dissapear on its own. As I mentioned, there is a scan tool procedure to correct this, and a Paragraph in your owners manual, so there is no excuse for the dealer to say such things, But at the same time, There is no reason for it to be at the dealership with this problem in the first place.....

I half sarcastically tell select customers , all the time.....It isnt MY responsibility to translate your owners manual into STUPID...I can get you one in French, Spanish, Dutch, Russian, Chinese , or any other language you wish, but they dont write them in STUPID.
30, 40, or even50 thousand dollar piece of equipment, and they gave you an instruction book..There is no excuse to NOT KNOW what each and every light , buzzer, bell, and button in the vehicle are supposed to do..Im a Tech, I fix them when they are Broken.....It isnt my job to sit and READ YOU A STORY AT BEDTIME , like a 3 year old, when all of your answers are in the Insruction book that you never bothered to read.
Maybe a bit Harsh, But if you bought it used and you didnt order an owners manual, ...Shame on you , your a FOOL. You Bought a House, And you have no idea where the circuit breaker box is????? Or the water main shut-off....??? Your Vehicle is just as critical, if not more.

 

There's no reason to make customers feel bad about paying you to work on their vehicles. They pay YOU to be the expert.

 

Granted..... and point well taken, But.....

Think for a moment.....If you come home and there is 8 inches of water on your kitchen floor, and the wife and kids are all huddled up on the countertop......

The last thing you want to hear is ..."I DIDNT KNOW HOW TO SHUT IT OFF"...

In similar situation.... You spent 30, 40 or 50 thousand dollars on a piece of equipment...IT IS YOUR RESPONSIBILITY TO KNOW HOW IT WORKS....

It doesnt become my responsibility until it doesnt WORK PROPERLY.....

Now..as for being the expert..True ...I am paid for that...and when a customer comes in with a problem like this, it is usually (But not always) explained that if it is an operator error, it WILL NOT be covered under your warranty. At that point they have an option of walking away....

If they agree to the diagnosis fee......I will usually clear it, and have The service manager release the vehicle as a "Tailight bulb"...10 bucks...and Im paid, the customer is happy, and all is well.....

Here on the forum, ...This is my time, my electric, my service provider, and My SATISFACTION of knowing that I tried to do my good deed for the day.....

I doubt it, but if there is a Salary for answering questions here, No one told me, So I do it for my own Satisfaction....Why then, on gods good green earth, do I have to show courteousy towards someone who didnt even bother to read my detailed explanation of how it works and what to do.....Nor the Manufacturers Instructions on what it is supposed to do....

The original poster got her question answered, and never showed up again.... This guy explained how he did what I explained NOT TO DO...but doesnt understand why it still doesnt work....

The parts store got the money for their cap...The dealer got their fee for giving him the WRONG INFO....I didnt get a Nickel out of the deal...HOW AM I THE BAD GUY?????