P0442 code 200 SL2
 

I've previously posted this summer about a few fixes I've done to clear out the codes on my car, and all was well until last week when the SES light came on. Autozone read the codes and printed out a "P0442 Small Leak in Evaporative Emissions (EVAP) System"

The Autozone computer also said the fuel pressure sensor was the most likely culprit and is often replaced when this code is detected.

I've searched the forum and have yet to find anything about a fuel pressure sensor, but do see suggestions to change the fuel cap or the gasket on the cap, something which I did on the first go-around this summer clearing and fixing the codes. I did go check the gasket anyway, and cleaned the filler neck that meets the gasket. I did use a gasket from a locking cap I had, it was the right dimensions but maybe I should just replace with the real thing. It is starting to get some very small cracks, so maybe that is it, but wow, these are very small and almost need a magnifying glass to see.

I have replaced the ECTS and connector from the Chevy dealer and things are fine there.

Also suggested were to check the vacuum lines. I'm having a hard time finding the vacuum lines, is there a diagram for the 2000 SL2 for the lines? I see the big line going to the canister by the radiator, but it was getting dark and couldn't make out other vacuum lines.

Thanks for any suggestions,

Kent

You can't trust those clowns at Autozone. For the most part, they hire people with little to no experience with cars. That's how they get cheap labor. Anyway, the code you're showing could be as simple as a loose gas cap. Check the seal on yours and clean it and the filler neck. Make sure when you put it back on that you hear it click a few times. Clear that code and then see if it comes back. If the code comes back, try replacing the gas cap with a new one. Cheapest and easiest thing to do.

You will more often get an 0445 evap leak LARGE if the gas cap is the issue, since once the gasket gets past its useful life, the seal between the cap and filler neck, which must be PRETTY DAMN TIGHT to stop ANY vapors from escaping.

If you can see cracks in the gasket AND it is not original to that cap, you don't really know if the combo of gas cap + gasket is truly sealing.

Is it possible to get a p0442 with a gas cap issue? sure.
Is it possible to get a p0445 with a gas cap issue? sure. It's just more common to have the 0045 snce a leaky gas cap gasket lets a lot of vapors escape.

I believe the fuel pressure sensor is back there by the evap solenoid, etc; I think when doing the EVAP system test it pressurizes the fuel system in the rear of the car, measures the pressure w that sensor, then measures at a set time later to see how much, if any, vapors have escaped. I'll look for a pic

The next day I cleaned the top of the filler neck and the fuel cap gasket with some silicone on a paper towel. The neck was especially dirty and bumpy feeling, but it became smooth and clean. This must have done the trick because after three driving trips the SES light turned off. I'll be filling up tomorrow so I'll be checking the cap again.

Far out, man! Let us know what happens.

i'm going to go across the street to my neighbor's and see if we can handle his large evap leak the same way.. Thank you for the tip

It's been a month and the code has not come back, so it looks like it is fixed. Derf, did this work for your neighbor?

Actually, he had some major knock sensor problems on is 2005 5.3 V8 in addition to the 0445 hew was getting. In PA, if you spend up to $150 trying to address each code at least once (receipts required), you can get a 1 yr waiver.

He needed new plugs plus wires (not cheap for that truck) nor the addl labor which was added into the parts cost as we could not even get the boots off the plugs, even with the proper tool.

Anyway, we had to throw money and it and splurged for the AC Delco OEM replacement gas cap. Filler neck mating surface was nice and smooth -- no reason to not seal.

I hand checked all hose connections under the car and found nothing loose.

Personally I think the evap vent is not closing all the way even though the solenoid is trying to make it do so. Now that he is on the road driving legally, we can sort it out at a slower pace.