P0442 99Sonata GLS
 

Hello,

I have been getting a P0442 on my 99 Sonata for the past couple of months.
It happens typically a day or so after I put gas in the car (may be a
coincidence). I have replaced the gas cap which I bought at the dealer.
Every time I get the code, I end up reseting it by disconnecting then
reconnecting the battery, but the code will come back. What can I look
for? Where are the obvious things to look that would throw this code?

Thanks