Emission Control System Leak Large
I have a 2005 Chevrolet Silverado 1500 and the other day the engine light came on. The Chevy dealer said the check engine light is related to the emission control system and that I could keep driving the car. I took the truck to Auto Zone and they let me borrow their engine code reader for free.
2005 Chevrolet Silverado P0455 Trouble Code
The reader reported Engine Trouble Code P0455 Emission Control System Leak Large. In my case just before the engine light came on I filled up my gas tank. I noticed the cap was not screwed on properly. After filling I screwed the gas cap on until it clicked and it was now sealed. This is when the check engine light came on and the P0455 Engine Code was generated. I used the trouble code reader to clear my codes and the light went off and stayed off. This makes sense because engine code P0455 indicates a leak which there likely was when the gas cap was not sealed. After sealing and clearing the trouble codes the system was no longer generating code P0455. If after clearing your code you still have the check engine light on and code P0455 appearing you should take the car or truck to your dealer or look at other parts of your emission control system for leaks.