Q: Check Engine Light on and off, reader gives P0446 error 1999 Toyota Corolla

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Two days ago, my check engine light came on and stayed on for about a day and a half. I was able to get a read on it and it came up with P0446: recommended replacement of the Engine Control Computer. Later that day, the light turned off. What should I expect in regards to cost and the level of importance on replacing?

My car has 137000 miles.
My car has an automatic transmission.

Hello - the P0446 code is an indication that the evaporative emissions purge valve electrical circuit has had a loss of electrical power to the vent valve that allows fresh air to enter the evap cannister. This could be a wiring problem to that valve, or a problem with the purge valve itself. It is unlikely that the engine computer needs to be replaced for this problem. I recommend a evap purge valve inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, confirm this diagnosis, and give you an accurate assessment of damage and cost estimate for repairs.

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