Code P0456

[Northeast Merc]

Hello All,

I dropped into Auto Zone today to try and get a handle on my check-engine-light issue ('03 GM).

The kid read the code as P0456: small EVAP leak. I bought a new gas cap in the hope that this might kill the problem. Next, I'll check for fractures/pinholes in the filler, and then I'll go and inspect the EVAP canister.

If anybody's been down this road with a similar-age Merc and has a tip to share, I'll buy the brew.



Thank you,


Jim

[sly]

Typically just take the gas cap off and clean the seal and put it back on. At least this is what has been done on my mom's old 2001 taurus twice now. Needs a cleaning about once every 3-4 years. And by cleaning, I mean rub your finger on the rubber seal to clean the dirt off and you're done.

[Northeast Merc]

Thank you Sly,

I'm running the new cap right now, but it doesn't have the plastic tether to the body. If I lose the CEL, maybe I'll give the existing cap a good cleaning and reinstall.

As a note, there are tiny abrasions in the o-ring of the old cap, so I wonder if it's possible that this created a minuscule leak. I'm hoping to lose the CEL in less than a hundred miles. I bought the GM for my daughter, and I'd like it to run the way it should. I picked up a '95 Town Car for myself about two months ago, and I'm as impressed with this car at 159K as I am with my daughter's GM (137K now). Great cars, and I didn't spend a ton of money. think a lot of mileage-conscious buyers are afraid of V-8s. I pull 25 to 26 mpg on the highway with my Townie--and at a high level of comfort.




Jim

[sly]

that could do it. The cap on my mom's old taurus was fine, just dirty.

[Northeast Merc]

that could do it. The cap on my mom's old taurus was fine, just dirty.

Sly,

The CEL disappeared in less than fifty 50 miles. I think I'll leave that new cap on for a while, mostly because of the slight abrasions in the original.

This was actually a lot of fun to diagnose and "repair." As I mentioned, I bought this car for my daughter who is now nineteen. I kept her in the loop for the whole process, reading the owner's manual, repair manual, logging into this forum, and when I returned from AutoZone I showed her the ticket with code printed out and told her about the new gas cap etc.

The thing is, she has no interest in cars, and this is OK. But, she does have an appreciation for how they're maintained and repaired and this, of course, is a good thing. She already knows how to change a tire, and I included her on the recent oil change. She spent a little less time on facebook that day, but I'd like to think she had a lot more fun draining an oil pan.

Again, thank you for your help with this.


Jim

[sly]

+1 family time