Toyota Sienna 2002 - Check Engine Light On

My Toyota Sieena has the engine light on. The Toyota dealer after two days of dianostics concluded that the catalytic converter need to be replaced. I have don e the emission about two months back and that was passed with out any problem. I noticed some power. I am wondering if the catalytic converter is the problem it may be some sensors in the exhaust system. I have read on different posts that people with the same problem have replaced the catalytic converter with after market parts but the check engine light did not go off. The reason given that the OEM catalytic converter should be installed for the check engine light to go off.

Get a second opinion. It shouldn’t take two days to read the computer codes, and a six-year-old vehicle (hopefully) shouldn’t need a new cat.

My cars are 11-12 years old and still functioning with their original catalytic converters.

Tell them to replace the O2 sensors and see what happens. Maybe the light will go off.

What’s the exact code (e.g. P1234)?

So, they propose to remove and replace the symptoms, do they? Unless the causes are removed, the symptoms will return.
Something happening before, and, during combustion, has damaged the catalytic converter (and, maybe, the oxygen sensors). Those causes need to be fixed. Possibilities are: excessive fuel, burning oil or anti-freeze, excessive misfiring, excessive leaning.
If the causes aren’t fixed, any new catalytic converter will fail…sooner, rather than later.

My 2002 Toyota Sieena also has the check engine light on, VSC light & Traction control. The car has around 130K miles on it. The Toyota dealer also told me the diagnostics concluded that the catalytic converter need to be replaced to a tune of around $1400. I also was wondering if the catalytic converter is the problem or some type of Oxygen sensor problem, etc. Also, I live in Oklahoma and for months, almost all stations have been using up to 10% ethanol in their fuel. Will this make the catalytic converter fail sooner? Thanks for any information!

First thing I do now is check the battery connections. The light came on on my grandson’s Ford Queen Vic. (98) during the middle of a 150 mile trip. Thought it might be the oil & added almost a quart & took off & the light was still on. While looking at the engine after we got home, I noticed that the ground cable lug was loose on the battery & actually, it turned out to be corroded & eaten through, so I put one of those lead lugs on & started the car up & noticed that the check engine light was now “out”. So I’m guessing that a bad battery connection can cause the light to come on.

zuko,
You disconnected the battery. On most older vehicles, doing that erases the code, and turns the check engine light off. It doesn’t fix anything. Flukes can happen to turn the check engine light on. So, erasing the code/light is the first thing one should do. Then, when (ok, IF) the light comes back, you know you have a real problem.
Seek out a capable mechanic to fix your car by doing a Dr. House on the “patient”; not, by removing major parts on the “patient”, experimentally.