2004 lesabre gas cap

[jswjsw1227]

Hello I was wondering if anyone has ever had the "gas cap loose check cap"on the dic.I have it on all the time now on my 04 lesabre it's annoying, and there is nothing wrong with my gas cap,it's fine and on tight as can be .Is there any way to turn off the message on the dic??Thanks

 

[imidazol97]

You can check for exactly what P code it is with a scanner.

The likely result is a small leak, which most likely is a gas cap. But can be caused by
other ways for air to get in when the computer runs a vacuum check looking for leaks.

Have you checked the rubber seal on the cap and the area it seals against on the
tank opening to be sure that area isn't rough? Coat those areas with vaseline for a good seal?

If the DIC code came up due to someone not putting the cap on after fueling
or not tightening it, the system runs the vacuum check when the tank level is
between 3/4 and 1/4 full AND when the engine is luke warm at start up.
If the light came on it may not turn off until the vacuum check has run and
has been passed.

A defective purge valve can sometimes be the cause. But the P0XXX number
can help.

 

[2007LucerneCXL]

White lithium grease on the mating surfaces where the cap and fuel inlet meet is another option that may work.

 

[imidazol97]

Yup.

 

[Homer Jay]

As suggested clean the fuel neck . Additionally If the cap is original, replace it. Sometimes the problem is not apparent, for example you're not able to fully tighten the cap due to weakness of the ratching mechanism.

 

[HotZ28]

If you have a "gas cap loose check cap" warning and related CEL, that could point to anything in the EVAP system and would show up as a small leak in the system. That is one of the more complicated things to diagnose. You may need to have a smoke test conducted to determine where the leak is!