CEL P0455

[cas951]

I've had this code for awhile. Changed the gas cap and problem still exist. I've read various forums on what could cause this and read up on them. I had no way of testing to pinpoint the issue so I brought it in to a Independent shop. They did a smoke test and could not find a leak.

 

My only other option was the dealer so I took it in to Stevens Creek Porsche.

They performed a smoke test and determined these parts to be faulty/leaking so they replaced the following parts:
1. 996-201-221-07 ACTVD CARBN CO
2. 996-605-201-01 SHUT-OFF VALVE
3. 996-605-213-01 CARBON CONT VA
Codes were reset. After driving the car around for a few day (65 miles) the CEL came back on. P0455 and also a P0430. I'm almost certain these two are related.

I am bringing the car back to the dealer and need to be prepared with what they may claim.

Any advice ? Can an Evap leak cause the P0430? I'm also holding them responsible for the P0455 code.

__________________

[JFP in PA]

 

I've had this code for awhile. Changed the gas cap and problem still exist. I've read various forums on what could cause this and read up on them. I had no way of testing to pinpoint the issue so I brought it in to a Independent shop. They did a smoke test and could not find a leak.

 

My only other option was the dealer so I took it in to Stevens Creek Porsche.

They performed a smoke test and determined these parts to be faulty/leaking so they replaced the following parts:

1. 996-201-221-07 ACTVD CARBN CO

2. 996-605-201-01 SHUT-OFF VALVE

3. 996-605-213-01 CARBON CONT VA

Codes were reset. After driving the car around for a few day (65 miles) the CEL came back on. P0455 and also a P0430. I'm almost certain these two are related.

I am bringing the car back to the dealer and need to be prepared with what they may claim.

Any advice ? Can an Evap leak cause the P0430? I'm also holding them responsible for the P0455 code.

__________________

 

 

Normally, P0430 is a code that indicates a failing three way cat.  That said, diagnostics protocol on a P0430 code is to address and rectify any other active codes first, then reset the system and see if the P0430 returns.  This is done because other faults can trigger the cat fault, and because cats are bloody expensive to be replacing without good reason.

 

In your case, I would go back to the cause of the P0455 code first.  As they have already replaced the vapor canister and two vales, there are still other connections, hoses, and valves in this system that could still be leaking (the code is for a gross vacuum leak in a complicated system):

 

[cas951]

Thanks JFP. Yes this is my intent. Have them resolve the Evap leak and rclear the code.

[KMN]

I've been living with the P0455 - Gross Leak - for the past 3 to 4 years mainly because I didn't feel like dealing with it and because I didn't want to spend time and money for something that didn't matter until the MD emissions test which is every two years.  

 

I would typically reset the CEL and drive for awhile and then to Emissions.  That worked two years ago, but about a year ago, the light came on almost immediately after I reset the CEL.  Since my Emissions was due in a few weeks, I decided to figure this out because I knew it wasn't going to pass.

 

To make a long story short, after spending hours researching, I was convinced it was my EVAP Purge Valve  so I had it replaced.  

 

The car passed emissions and the CEL is not on and life is good.

 

My bet it is the EVAP Purge Valve.

[JFP in PA]

Believe it or not, the most common cause for P0455 is bad gas cap seals.  By far, in the shop, most of these codes are leaking or even missing gas caps.

[KMN]

No argument from me regarding the gas cap...but I already changed mine out...besides, the gas cap is the first (and cheapest) thing to replace first...but if that doesn't work, then it's down the laundry list...however, I'd be willing to bet that more times than not, it's the purge valve (after the gas cap)...

[Pete03S]

Note, if you have changed the Fuel Tank Vent valve (the one up by the filler neck) you have to make sure the sensor that goes in between the filler tube and the sensor is installed correctly.  Mine fell out while changing it, so in addition to the noise I could not fill the tank.  I took it all apart again and installed the sensor that sits in between the fuel tank vent valve on the filler neck.  Put that sensor back in the right place and all is well, the noise is gone and I can fill with gas again.  : )