2004 Chevy Silverado fuel cap

2004 CHEVROLET SILVERADO
80,000 MILES • V8 • 2WD • AUTOMATIC
Avatar
TEXASPEACEOFFICER
  • MEMBER
  • 2 POSTS
my check engine light indicating my fuel cap needs tightening keeps coming on. I have replaced the old fuel cap with a new one, but when my tank has about 1/4 left, the check engine light comes on telling me my fuel cap needs tightening. How do I fix this??????
Oct 8, 2009 at 1:17 PM
Advertisement
Avatar
SERVICE WRITER
  • ✓ASE Certified Mechanic
  • 9,123 POSTS
  • ASE Certified Mechanic
the light is detecting a loss of fuel vapor, not necessarily the fuel cap. The code is po442 maybe?

This means that there may be leak elsewhere in the evaporative system such as a fuel filler neck for example.

Verify what code # is there and get back to me.
Oct 8, 2009 at 1:41 PM
Avatar
TEXASPEACEOFFICER
  • MEMBER
  • 2 POSTS
the code is po455


[quote:a5eda2f37e="Service Writer"]the light is detecting a loss of fuel vapor, not necessarily the fuel cap. The code is po442 maybe?

This means that there may be leak elsewhere in the evaporative system such as a fuel filler neck for example.

Verify what code # is there and get back to me.[/quote:a5eda2f37e]
Oct 14, 2009 at 10:06 AM
Avatar
SERVICE WRITER
  • ✓ASE Certified Mechanic
  • 9,123 POSTS
  • ASE Certified Mechanic


https://images.2carpros.com/forum/automotive_pictures/30961_evap_3.jpg

This is a large leak, and a vacuum can not be drawn on the evap system. Check the connections as per the drawing to make sure a hose is not off or damaged. A valve stuck open will also do this. IF none, you can either have the system smoke tested or pull off the vent valve and check for any dirt inside of it. Replace if so. Why so many different user names? https://www.2carpros.com/forum/modcp.php?mode=ip&p=689171&t=357139&sid=e3bce73e7d2f32702cf386a99e09382d
Oct 14, 2009 at 1:08 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.