Tighten Gas Cap

[Stett]

"Tighten Gas Cap" every time I drive. :upset: I read somewhere that the Camaro does a self test every every cycle (~5 miles after startup) and that does feel about when the message comes on in the DIC.

That thing cannot get any tighter. I just filled up my third tank of gas since taking delivery and the cap feels tight. I've taken it off and replaced it a number of times, and twisted it till it clicks. I've even attempted to keep twisting, but there's no way it will turn any further.

Took it to the dealer last Saturday along with the creaking drivers seat issue, and they ran fuel system check and everything passed. They cleared the code. Sure enough it came back on the following day, and no the gas cap had not been removed in that time.

Anyone else experiencing similar on the new 11s? I read a good amount on the older 10s, but haven't seen anything mentioned recent.

[ffrcobra_65]

bad cap I bet.

[71cam]

Originally Posted by ffrcobra_65

bad cap I bet.

sounds like it to me too.

[Evil35th]

We had the same problem with one of our G8's. It turned out that the connector on the filler tube was not seated all the way.

[Stett]

So update:
I took it to the dealer this afternoon (3rd time) and they tested it for 3 hours and found no physical problems with the fuel system at all. On visit 2 they replaced the sensor thinking that may be faulty.

The problem is it keeps throwing code P0455 for Large Evap leak, but there's no leak. They cleared the codes and nothing came back during the 3 hours it was being tested, and nothing in the hour long drive back from the dealer either.

They've offered that if it happens again that they will be contacting Chevy's Technical Service to get them involved. My hunch is that it's software as the warning comes up during the system self test while driving, but they updated the ECM twice already.

[SC2150]

Easy enough to turn the DIC warning off w/HP Tuners or EFI Live.....just that specific warning.

[Russell James]

Did they do a smoke test?

It's not the software. Every one has the same software. It's a hard part failure, something like a hose off for that code. With a brand new car, the most likely cause is an assembly issue like an evap hose not connected properly.

[speedster]

We cheated...



Hope you get it figured out.

[Stett]

Originally Posted by Russell James

Did they do a smoke test?

It's not the software. Every one has the same software. It's a hard part failure, something like a hose off for that code. With a brand new car, the most likely cause is an assembly issue like an evap hose not connected properly.

All hoses are connected, they ran a smoke test on 3 separate occasions, no leaks anywhere, not even any micro leaks. They specifically checked the evap hose and thats fine. This code is supposed to indicate a large leak, but that's the problem - there is no leak.


My thoughts are that since there's no physical leak, but the system thinks there is one, the problem lies within the notification system. They replaced the sensor last week thinking it may have been faulty. The next biggest common factor is the programming.

And tuning out the CEL so it doesn't throw a code (even only a specific one) is not an option. I can understand if its loaded full of aftermarket parts, but this one's 100% stock.

[Russell James]

Below is the description on how the diagnostic check is run.

It involves 2 solenoids, vacuum line, wiring, ECM, and the tank pressure sensor.

Smoke showed no leak, changed the sensor, I assume they tested the cap and neck sealing surface. That leaves the possibilities as;

a pinched vacuum line/restriction
bad solenoid
a wiring open, short or ground

The service manual has a procedure to hook up the special tools and run several test procedures while manually triggering the diagnostic test.

They'd monitor the vacuum while the test is being run. That will rule out restrictions and leaks. If there are no restrictions and leaks, and both solenoids are operating to create the vacuum... then the signal back to the ECM needs to be checked to see if the sensor is telling the ECM that a vacuum was achieved. If there is no signal at the ECM, the wiring/grounds needs to be checked.


Description from the Service Manual:


"This diagnostic creates a vacuum condition in the EVAP system. When the enabling criteria has been met, the control module commands the normally open EVAP canister vent solenoid valve closed and the EVAP purge solenoid valve open, creating a vacuum in the EVAP system. The ECM then monitors the fuel tank pressure sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. Failure to achieve the expected level of vacuum indicates the presence of a large leak in the EVAP system or a restriction in the purge path. The ECM will log a fault if it detects a weaker than expected vacuum level under these test conditions."

[pennor]

Originally Posted by Stett

"Tighten Gas Cap" every time I drive. :upset: I read somewhere that the Camaro does a self test every every cycle (~5 miles after startup) and that does feel about when the message comes on in the DIC.

That thing cannot get any tighter. I just filled up my third tank of gas since taking delivery and the cap feels tight. I've taken it off and replaced it a number of times, and twisted it till it clicks. I've even attempted to keep twisting, but there's no way it will turn any further.

Took it to the dealer last Saturday along with the creaking drivers seat issue, and they ran fuel system check and everything passed. They cleared the code. Sure enough it came back on the following day, and no the gas cap had not been removed in that time.

Anyone else experiencing similar on the new 11s? I read a good amount on the older 10s, but haven't seen anything mentioned recent.

YES!!!
I'm having exactly the same problem!

Started at 80 miles 10 days ago and I was back in the dealership today for the 3rd time with this exact problem. I have a 2011 2LT/RS.

[pennor]

Originally Posted by SC2150

Easy enough to turn the DIC warning off w/HP Tuners or EFI Live.....just that specific warning.

So you're saying to mask that code I should spend $400-$800 for a top-end scanner tunning tool? Give me a break! I'd love to turn off the code and mask it for all time, but not for that cost. How about a suggestion that's a little less expensive.

[pennor]

UPDATE:

Well, our 2011 went back to the dealer yesterday with the complete text of this forum subject. The service manager and tech assinged to the car were very interested in the fact that there are two Camaros, both built on the same day, with exactly the same problem. They promised me the car by late afternoon but have decided to keep it overnight so they can do further test when the system is stone cold. They seem to be narrowing in on a bad selenoid on the evaporative canister.

Stand by here, I'll keep you posted as they learn more.

[clg_98ta]

Has the dealer tried replacing the gas cap (for either of you)? If not, you might suggest that...