Ok so i found out what it means... DTC P0451 - evaporative emission control system pressure sensor range/performance....

anyone have any idea what that really means??!

 

More info needed, are you running any aftermarket parts? Tune? What were you doing when the CEL came on?

 

well i have my dual magnaflow exhaust on.. thats been on since sept. of like 05.. this just happened like 2 weeks ago...... i do have an intake with an X-cal II tune, but thats been on since january...... i did however, recently try to do my 93 octane tune... i had been runing my 87 tune since january.. well anyways... i thought i got the tank to pretty much empty empty.. and my dumbass only put 2 gallons of 93 in and when i started to run the car on the 93 octane tune, well things didnt go so well... so i just filled up with 87, flashed back to my 87 tune and went home.. next morning.. the CEL is on.... i know i shoudlve filled up all the way with 93 octane gas... but yea hopefully that gives you a better understanding of the situation...

to note.... i had to bring my car in to the dealership so i took my off my intake and reflashed back to stock and the CEL is still on.. they said i need a new PCM, so they ordered it 4 days ago.. so whatever.... i dont know

 

If you ran your car down to "nearly" empty you more than likely still had at a couple of gallons in the tank. Then when you put the 93 octane in it blended with the existing 87. You probably would have been OK had you filled up with 93, but since you only put 2 gallons in you ended up with a blend of about 90 octane. I'm not surprised it ran bad on the 93 octane tune! Next time you try the 93 tune, note that you are actually supposed to fill up 2 or 3 times with 93 BEFORE you switch the tune. This is to make sure you're not watering down the octane. I hope you didn't run it too hard while on the 93 tune, did you hear any knocking?

 

no i drove like 3 miles to work... then 1 mile to a gas station 5 hours later to fill up with 87 octane gas

 

remove then reinstall your gas cap

 

.... well ive filled up since then and checked the gas cap and all seems fine.... error code still present

 

hmm wonder if something went wrong with the Evaporative Canister..... could have nothing to do with the tunes...... but again I am no expert ,just keep an openmind when troubleshooting.....sometimes things just break

 

wheres that

 

its the black square thingy hanging down from your rear bumper, right under your trunk in the center