Here in California it's an automatic failure on your smog renewal to have a check engine light on... even though they clearly see it is on... they say nothing... take your 49.00 dollars... run the test... then fail you... then tell you that you have to take care of getting the check engine light being on... even though it could be as simple as a gas cap being loose... the smog people have gone haywire here in California... my advice to anyone with a check engine light on... research it on the internet... to see if it is something simple to fix...
If you clog your cat and drop gas mileage, you may want to heed the engine light. Clogging the cat or shuting down in the middle of nowhere is not fun. Plus you fail inspection.
I purchased a 99 Camry about 3 years ago, it now has 161,000 miles on it. The only (major) problem I have had with this car is the starter motor shorted out, and fried itself and the battery. I have changed the oil every 3000 to 4000 miles, and have never even seen the check engine light. Do have the knocking sound in the rear area when going over bumps, was thinking new struts may fix that, but after reading some reviews, that may not make the noise go away.
Yes, my mechanic said it was OK to drive with the check engine light on, because everything checked out OK, but it's driving me crazy. He used a diagnostic calculator on it, and it went out, but came back on after about 20 miles. I'd just like to get it to turn off.
Love the car, it's had regular maintenance on it since it was new, now has 166 thousand miles on it, and I expect at least 200 - 220 thousand miles (maybe more) before I have to get something new.
My wife's car just passed 4 years with the "check engine" light glowing merrily. The car runs as good as new, has shown no power loss and gets the same great gas mileage as always. At Christmas I will just add a small green ring around the light and regard it as a Christmas decoration!!
Why not go to auto zone and have the hand held scanner check the codes? Then you know. Buy the part and fix it. You can drive around with an O2 light on as well. Then you get lousy mileage and the chance to buy a new cat converter sooner.
Obviously someone didn't fully read comment 12:47. It clearly states "The check engine light has been on for FOUR YEARS". It also clearly states that the car still runs as good as new and has not suffered a drop in fuel economy. A malfunctioning oxygen sensor causes noticeable symptoms well before 4 years. I've driven my car for two years with the "check engine" light on. It codes as "engine running too cool". The heater works great, the gas mileage has actually gone UP, and cooler-running engines are under less stress. I see no point in "fixing" something because my super-sensitive computer thinks there is a problem. Let's face it, 99% of all issues triggering "check engine" lights are designed in by greedy car companies seeking extra money from people who are afraid their car will explode or quit on them. A piece of black tape over the light is cheaper and lasts longer than most of the "repairs" done to shut off the little light (which usually consists of hooking a scan tool to the car, and charging the owner several hundred bucks for turning it off).
It's getting stringent on the east coast as well. Have a light on in De or Md; they fail inspection. Md has a dedicated inspection place for this. DE has 2 tests, and it's computerized. They plug in under the dash now. And if you fail; no tags. You rev your engine for the emission test next. Guess they don't want ratty polluters on the road anymore.
18:13 I saw a TV court show that someone covered over a dash light. They paid for it dearly when they sold the car. I just bought a 02 socket for my tool box for under $8, and bought a new sensor. 10 minute fix. What is really expensive is a new cat. Sometimes it's a simple as a loose gas cap. I had a smoke machine hooked up, and found just a minor hose leak. It's not the end of the world to solve vs cover up with a marker or black tape.