Service Engine soon...

I have had the same problem with my Nissan Maxima. I heard the same thing from numerous people... tighten your gas cap. I tried this and even bought several new gas caps. Nothing worked. I finially replaced the sensor for about about $350. It has fixed the problem. Hope this helps. Now at least I can pass my emissions test. You need to get this problem fixed because having that sensor broken can cause other sensors to break, which will cost even more money to fix.

Its time for service.. check the mileage,

IMO, far more likely to be a fuel tank cap not properly installed. ie. unscrew the cap, remove it, and screw it back down carefully until it rachets. Drive for a day or so and see if the light goes out.

You can always check with a dealer who can read the code causing the light to come on, but $$$.

Good luck.

Or you can go to your local AutoZone and they'll read it for free.

Or you can make it blink out codes yourself. Here's the procedure from the

They recommend you use a watch with a second hand to do the timing on this.

1. Insure the accelerator pedal is fully released, then turn the ignition on (warning lights on, but don't start the engine) and wait 3 seconds
2. Repeat the following procedure quickly five times within 5 seconds: 1) fully depress the accelerator pedal. 2) fully release the accelerator pedal.
3. Wait 7 seconds. fully depress the accelerator pedal and keep it down for approximately 10 seconds until the MIL starts blinking.
4. Fully release the accelerator pedal. ECM has now entered Diagnostic test mode II and will blink out self diagnostic results.

It blinks out 4 digit codes, 10 blinks represents the digit zero. The 1,000 digit blinks on for .6 seconds and off for .6 seconds. The other digits blink faster - .3 seconds on, .3 seconds off. Digits are separated by the light going off for 1 second. The change from one four digit code to the next is indicated by the light going off for 1.8 seconds.

It keeps blinking out the code(s) until you stop it. A code of "0000" means no problems detected.

To erase the stored codes (and reset the light), while it is blinking out the codes, press the accelerator pedal down and hold it for more than 10 seconds. (If you don't want to erase/reset it, just turn off the key.)

Post whatever code(s) you get and somebody here will probably look it up for you.