How much do it cost to replace a sensor on cars?

You can always open your gas tank filler. Get the problem diagnosed and quit being a dumb ***.

"A sensor"? There's several on modern automobiles. Be specific.

OPEN THE TRUNK and there is a WIRE that will open it! WIth a TAB on it! READ YOUR MANUAL ABOUT THIS silly!INCLUDE YEAR and ENGIEN SIZE!!! I think some Jettas are MADE inthe USA like PASSATS ARE and a few AUDI cars.

Get a scanner first and read the trouble codes.