I have a 2006 Scion tC. It has roughly 118,000 miles. Everything has been kept up on the car. This would be the first problem that I have. Two days ago the check engine light came on. I just went up today to have it checked out. The readings that came back for possible causes were:

Defective or loose fuel cap
EVAP canister or hose cracked-not connected
Purge or vent solenoid defective
Vacuum leak at engine

The reason I asked about the vacuum leak is because when idling, it is kind of rough, just noticeable. Gas mileage is still good and so is everything else. That is why this was kind of a shock. There has been no signs of anything wrong. So any help as to how I can check this would be great. Or just advice period. Thanks for your time.

 

whats the code.......have you ever cleaned the maf sensor,since its a high milage car,

 

There were three different codes: P0441, P0455, P0456. And no I haven't ever cleaned it.

 

check to make sure,your fuel cap is securely,screwed in,3 clicks,clean the maf sensor,make sure theres no damage vacuum hoses...the rough idle indicates,theres a sensor dirty,so i would clean the maf sensor first and see what happens

 

I would also make sure your plugs are good and the coil's are properly seated.

 

I am have the same issues, my CEL was on but after seafoaming it , changing the oil, and changing the plugs it turned off. I'm knew to this scion stuff since i used to own a Eclipse GSX. All this naturally aspirated engines always seem to give me issues. I've cleaned out the MAF. still idles rough though. It idles at about 400rpms. I give it some gas and it seems to smooth out. If anyone has any advice let me know. If there are any better forums than this one let me know as well. Thanks in advance.

 

Long shot, but try taking off the intake from the throttle body and clean it out, I had a rough idle/stall issue a couple months ago, cleaned the deposits off the throttle body and they disappeared, got a few MPG better too, motor ran smoother and everything.

 

Ok. So I tried cleaning the MAF and replacing air filter. I reset the Check Engine light. Well it came back on. I notice that the air conditioner doesn't blow cold all the time. It has freon in it though. Could that be a sign of a vacuum leak? I am not sure what is going on, or where to go from here. Any advice on this?

 

a/c has nothing to do with the emissions check engine light code you've got. the a/c issue is from the system not being up to it's max capacity of refrigerant (r-134a). This car, to be cold, has to have the max amount inside otherwise it's not very cold. Another problem is the schrader valve that is on the High side a/c fill port. It has been found to be loose, just needs a tool to snug it down. It's the same design as a valve on a tire valve stem, just bigger. I have found on mine and on some others that isn't tight, refrigerant leaks out over time, resulting in "not too cold" air. have a reliable mechanic check both.

also.. Have you checked your gas cap? Look around the lip of the fuel filler neck, where the gasket of the gas cap fits onto. Do you see any corrosion? If you do, stuff a rag down the fuel filler neck, then LIGHTLY sand the lip, the rag is so none of the sanding gets into the gas tank. That was happening to mine, learned that trick, and no more issues.

If there isn't any visible corrosion around the fuel filler lip, then get yourself a new gas cap at the dealer, clear the code, and it should not come back. The cap does go bad from time to time, it's the gasket that fails. When pressure (aka vacuum) cannot be kept inside the emissions system, the system sees it as a vacuum leak, and poof the CEL comes on. easy fix..