[SpyShops NY]

I sometimes get a message on my DIC saying to "tighten gas cap" I bought a new one not from dealer, from autozone. Sometimes when I go in the morning to drive I get the message it use to happen once a year now it happens almost every week now.

 

[BDuncan]

Check the plastic connecting strap that keep the cap from falling to the ground. I have had a slightly loose cap several times due to the strap pulling counterclockwise on the cap. I always hold the strap back when I tighten the cap so that the strap is pushing the cap tighter instead of the opposite. Also carefully inspect the top of the filler neck.

 

[hcvone]

We seen this at our shop and now only use factory cap caps and have no more issues, cost more but cheaper in the long run because of no more issure

 

[Waychoff]

Most times the problem is not the gas cap. This happened to me and after changing gas caps, I finally had the dealer run a code and it was the evaporative part in the emissions that was the problem. I think 75% of the time, this is what this means when "tighten gas cap" shows up in the DIC. Just wanted to offer this up.

 

[deronbrooks]

@ Waychoff, what did they do and what was the approximate cost of the repair? Thanks in advance

DB

 

[Submariner409]

Trace out the EVAP system - from the throttlebody purge solenoid back to the charcoal canister, solenoids, and tank vent fitting. ANY air/vacuum leak in that purge system shows as a "loose cap", among other faults/codes. Also, on some of these EVAP systems there's a test port in the engine compartment, covered by a green (tire valve) cap, on the vacuum line from the throttlebody.

 

[Zl700]

Same thing happened on my 07 Escalade around 100K
I replaced both the evaporative canister purge solenoid and the vapor canister purge valve. It was probably only one that was the problem but for the cost and time I did both. Parts cost under $100, took me 2 hours total.

Canister purge valve is on evaporative tank above spare tire, purge valve was on the intake manifold.