I am having the dreaded P0455 CEL on my 99 GS. I have been trying and trying to figure out where the components of the system are to no avail. From what I'm reading, they are located at different places on different models/years. Can anyone give me any info on the 99 GS? I'd GREATLY appreciate it!

If you have a 99 and are boosted, check the fuel vent valve which is located under the car right in front of the gas tank (towards the front of the car) The valve is not designed to see boost and the inner thin rubber diaphragm will eventually tear and cause that code. This is what it looks like:



If its not that, check the EVAP canister behind the front bumper passenger side vent. This can also be adversely effected by repeated boost.

If it is one or both of these, you can solve the problem(s) long term by using a 1 way check valve.

Good luck!

i like my CEL... its mesmerizing :whoa