My check engine light kicked on about 6 months ago. The code was for the catalytic converter, which I did not replace because it is less than 2yrs old. It would go on and off intermittently, and for the last week it has remained off. All the other dash lights work fine, and I know it’s not the fuse because I have had that poop ou on me before. Did my car heal itself or is it just easier for me to live in a state of denial?
'97 Toyota Camry, 231,000 miles.
Highly unlikely. It could be a faulty or weak O2 sensor that the code clears. Try some Cataclean. It cleans sensors and the catalytic converter.
The quick answer is yes.
On a 17-year-old car, you are due for some instrument cluster light bulbs to start burning out. If the check engine light does not illuminate along with all the rest of the warning lights when you turn the key to the Run position, I would bet that the bulb is burned out.
A '97 would be an early OBD II system car. On those cars, a catalytic converter code normally means that the post-cat oxygen sensor has gotten slow to respond. Was the sensor replaced when the cat was replaced?
If your car really destroyed a cat in two years, you must have some misfire problems or your gas station is selling you waste industrial solvents rather than fuel. (not a joke, some stations in California got busted for that a few years ago)
Hmmm, It was misfiring about a month ago and I had the spark plug wires replaced. The O2 sensor was replaced with the cat. Would it do any harm to try a product like Cataclean so I might pass the inspection this year?
The P0420 cat code can also be generated if the FRONT O2 sensor is old and sluggish
What engine do you have?
@Manolito the rear sensor is the monitor. Its signal should be steady, NOT fluctuating
Cataclean will not hurt the car. As stated Manolito, the lights should come on when the key is turned on and that will tell you if it is burned out.
Get one of those $25 OBD readers.
How do we know it is throwing a P0420? There are a bunch of codes it could be, like a misfire on cylinder X. He mentioned he had a misfire. An untightened/bad gascap throws a code, etc.
Listen to @hokiedad and get a cheap reader or go to Autozone/pepboys. They can read your code for free.
“The code was for the catalytic converter” I am assuming the code was P0420
Thanks for all the input. The O2 sensor was replaced last year. When the light originally kicked on, I had it read and was told it was the catalytic converter. I’ve since had work done, and the shop confirmed the original code, although I was never told the exact numbers. 99% the light burnt out. At his point I will just live in denial 
The CEL on most cars always turns on with the key in “on” but the engine not running. That’s the way to check if the bulb (or LED) is burned out.