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Service lite came on check it out and found Code PO442

What does this code mean and how do I fix it

This code indicates a leak in the car’s evaporative emissions system.
The first thing to check is the gas cap.

If the gas cap is tight and the gasket is in good condition, then further testing of the evap emissions system is necessary in order to find the leak. Unless you are skilled in this type of work and have the equipment necessary, you need to take the car to a qualified mechanic.

Evaporative Emission System Leak Detected (small leak)

It could be your gas cap, it could be a small leak in the gas tank or a hose, it could be a bad solenoid valve, and so on.

just had the same thing happen to me. my son borrowed my car and put in hi test gas( no need for that in my 2000 olds alero) had the same code. car was running fine .my manual said if you change brands of gas this might happen i took the gas cap off and put some grease on the neck filler and on the inside of the gas cap. i did fill it up with regular gas. i drove it the next day and the light went out, the same thing happen with my wife’s car (2004 buick lesabre) drove that for a couple hundred miles and the light went out. as long as the lights not blinking there is no major problem-- hope this helps --best of luck

Why would a comment that using “hi-test” gas could cause a P0442 code appear in a owners manual or any where else? an evaporative emission system an fuel octane don’t cause conflicts with eachother.

old school – i did not say " my manual said code po442 causes this problem" it did say changing brands ( which happen to be hi-test) might make service engine light come on-- i went to auto zone to get PO442 and it told me the usual things that po442 could be—gas cap vacuum leak, etc. hope this helps clear up your answer

Simply so our readers will not get confused, changing the octane of the gas you put in the car will not cause the “check engine” (or service engine) light to come on.

How often does you son borrow the car? How often does he put in gas?

Could be the son, not being a “frequent filler”, mis-handled the gas cap.

i know the hi-test did not cause the problem i said" changing brands "that’s what my manual said --how much more plain do you what me to be???

only because his car was being fixed — so i let him borrow mine— to get to work-- he lives 30 miles away— so i very " never’ let him take my car. AND YES HE COULD HAVE MIS-HANDLED THE GAS CAP

Let me ask you to make it clearer, what code do you think would be set simply by changing brands? many here don’t even go for the different brand idea (thinking it is all the same and just marketed different).

We have to remember impressionable people read what we are writing and the first rule is “do no harm”. What I mean is, people have enough misconceptions about that “check engine” light, we don’t need to add more to the list.

Golfnut, I’m sure your input into the discussion is appreciated, as your suggetsion on what solved your light is directly related to the OP’s problem.

Neither a different brand of gas or a different octane will have any effect on this code. The code is for a simple evaporative emissions system leak. What solved yours was really greasing the fill neck and the gas cap. That simply stopped the leak. The ECU will then reset itself after some miles if the system no longer detects a leak.

Your post is very relevant to the PO’s problem. It may be his/her gas cap leaking. It may even have simply not been put on correctly and if reinstalled may solve his/her problem. If it does not, a new cap may be in order. Or a smoke test. A smoke test is one where a machine is used to pump smoke into the empty spaces in the gas tank and its ventivation system and the smoke comes out where the leak is.

To the OP: try reinstalling the gas cap amd see if the light goes out after a drive. If not, try replacing the cap. They’re cheap to buy. If the light is still on, take it to a shop to have the EVAP system checked out.

MB,you are much better with words than me BUT you should said “this code or any other code”.Perhaps this omission was intended?

Action on this can be deferred until you need to pass an emissions test…

On my 2002 Sienna, several years ago, I would get intermittent failures with 0442 and a couple others in the same technical area. 0446 comes to mind. It was extremely intermittent, at times it would go several months without failing. At other times it would fail daily.

A new cap did not help. A new official Toyota cap did not help.

I realized from my own electronics work that it was probably a waste of time to take it to be fixed, since the odds of the mechanic even seeing it were abysmal.

I kept logs. Finally, a man on the Sienna Club said he had two Sienna’s and one had the problem. So, he swapped parts from one to the other, and when he swapped the charcoal canister, the problem went with it. He said the assembly seems to have some low pressure, self-actuated valves that may have become sticky.

I took it to the dealer, and requested they replace the canister without diagnosing the problem. They had me sign a waiver that I was taking responsibility for the repair, that if it failed to fix the problem they did not warranty it. I gladly signed, they replaced the canister, and it has been several years now with no more failures.

I worked for some years on military electronics which uses the same sort of “self-test” system that the OBD-II system is, and am quite used to the concept. That does not give me the experience that a good mechanic has, with car electronics, but the shop manual and the Internet are good helps.

by the way, the comments directed to golfnut about changing brands turning on lights, either he is mistaken or lying, OR, his manual does say that. If his manual does say that, I’d sure like to know it.

There was an explaination why a Honda would not throw a code and others would, but this was back around 1997 (not acurated with that date ± 3years). The reason was that Honda had more tolerent sortware in regsrds to when a code was set. This was an issue that either was settled or ended up in court, so there is a trail out there if anyone cares.

We had a similar situation with cell phone software in 1987 in Switzerland and Motorola. The Motorola software gave Motorola phones and advantage in time to complete calls (remember the was Europe in 1987). So the Swiss PTT (Post Telephone Telegraph) made us change out all software (about 4000 units) to the slower version

In regards to “golfnut” I feel his pain as I know first hand how things can go wrong, even when you have the printed report in hand. Secondary, I could have not even said anything about golfnuts comment, and just be done with it. I take no pleasure making a correction like this. I did make the correction simply because we have so many readers that do not understand the "check engine’ light parameters. Believe me I thought long and hard about posting a correction, I have never even seen golfnut here before, so it can’t been justifibly said I am “gunning for him”