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Check gas cap light comes on. I bought a new cap at parts store, cleared the code i think it was 409. 30 minutes later check cap light came on again. I read on here it could be the evap vent valve on the rear of the car but where on the rear and what does it look like. Any HELP would be greatly appreciated.

Clean up the sealing surface on the fuel filler where the gas cap goes.

After so many good cycles, the code might go away. Post back if it comes back again.

shawnyoung wrote:Check gas cap light comes on. I bought a new cap at parts store, cleared the code i think it was 409. 30 minutes later check cap light came on again. I read on here it could be the evap vent valve on the rear of the car but where on the rear and what does it look like. Any HELP would be greatly appreciated.

Some people have had trouble with certain parts of the evap system.

But Harofreak is right: check your gas cap sealing surface inside the tank opening and the rubber o-ring on it. Put petroleum jelly on the o-ring. Had you filled up with gas a day or two ahead of the problem light?

If the algorithm is the same as my 98's, when the tank is between 3/4 and 1/4 and when the coolant temp is between two moderate temps, e.g., 130 and 170, when the car is started is may run the evap leak test.

In other words if you tank is between those levels, run the engine to moderate temp before the gauge gets up close to the normal. Shut off the engine for a few minutes and then restart. See if it does the test and clears the light for you.

Good luck to you.

I have a 2000 SSEI and "check gas cap" light is staying on and now "service engine soon" light is staying on.
Tried a couple of suggestions from previous post: Replaced gas cap and cleared code, cleaned filler tube, put petroleum jelly on o-ring, started car and run to 150 degrees shut off and restarted, NOTHING has changed! No problems with air releasing when removing cap or filling car. Read on here it might be evap valve. Can someone tell me where the Evap valve is located??? Do not know what else to try. Any suggestions would be appreciated.

I have tried everything that was suggested and more. If I remove the evap valve and vapor cannister is there a way to check them to see if they are bad maybe even before removal? I Have searched the local parts stores for a service manual for the 2000 SSEI and they do not have one. Does anyone know where I can get one? Thanking you in advance for your help.

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