Hello

After i changed my battery. Everytimes i trying to turn on the car. It crank couple time before it can be turn on. This happens everytimes i try to turn on the car. Suddenly my check engine light on now. And the code show p0420 and p0430. Machanic man told me that means i need to repl as ce mt cats is that true?

 

Here's what I suggest based on what you have said. Toyota's have a tenancy to be very picky about their learned parameters. When power is lost (like in the case case of replacing a battery) all the learned data is cleared and the vehicle doesn't know how to run anymore. I had a newer tundra in this week and it was barely running. He had replaced the battery and the thing couldn't even start/hold idle. All I had to do was clean the throttle so that the reset parameter that the computer wanted to see was equal to what it wanted the throttle blade to sit at. See throttles get gummed up over years and the computer learns to hold the blade open more and more to allow air to pass through for a good enough idle. After the power loss and this data disappeared, it went back to it's origination position. Now instead of still being open enough to allow air to pass. It is closed into the gummed up area. This will cause the symptoms you are describing and misfires. Unburnt fuel and air from the misfires causes a lot of oxygen to pass by the o2 sensors and is picked up as poor cat efficiency. I believe your car is running so out of whack that it's throwing those codes. The first thing I would do is pull your throttle and clean it. Then see if you have an easier start/idle. Clear codes, drive a few days, and re-check. The throttle has everything to do with how that engine runs.