Q: Check engine light turns on and off

asked by on October 16, 2016

Hi, two weeks ago my truck started with engine light, code p0420. After 2 or 3 days turns off by itself. But last week turn on again and didn't turn off. I took it to autozone and they found p0420 and p0430 next two days engine light turns of by itself. What could be the problem? Any advice will be appreciated. Thanks

My car has 160000 miles.
My car has an automatic transmission.

Both of these codes are related to the oxygen sensor readings. More often than not, this will be caused by failing oxygen sensors. There could be other issues that can cause these codes, such as an engine misfire, failing catalytic convertors, or it could mean that the engine is in need of a tune up. It would be best to have a certified mechanic, such as one from YourMechanic, check the readings on the sensors to see if they are performing correctly, or diagnose a possible performance issue.

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