Check engine light came on thought it was the fuel cap light went off for several days hen came back on

See this possible fix:
https://www.scionlife.com/forums/maintenance-car-care-1604/cel-codes-p043e-p043f-p2401-p2402-p2419-142448/

Please contact randy on the original link for the first time you posted this, do not post a new question.

http://www.matrixowners.com/tsb/T-EG002-06.pdf

this sounds like your problem

CODE PO420 CATALYST EFFICIENCY BELOW NORMAL BANK 1. POSSIBLE CAUSES. THREE WAY CATALYTIC MANIFOLD. EXHAUST TUBE.INTAKE AIR LEAKS.FUEL INJECTOR.FUEL INJECTOR LEAKS.SPARK PLUG.IMPROPER IGNITION TIMING.

The old days of disconnecting the battery to make the light go out are long gone, It must be reset with a scan tool so try this go to advance auto and have them put it on a scan tool to find out what the codes are then have them clear the codes. If the light comes back on after that you may have to replace the fuel cap. I hope this helps you.

Take it to autozone. If you live in USA. They have a thing that checks and they will tell you exactly what the codes mean.

It's the gas cap sensor. Or you are getting a vaccuum leak somewhere.

There is a TSB on those codes to replace the evap canister module assembly. I THINK it is covered under the 8/80k federal emmisions warranty here in the US. (I'll check and get back to you) or you could contact your dealer to see if it is. That is not a cheap part to replace.

The P0141 code points to the O2 sensor heater circuit. It could be that there is a short in the wiring to the O2 sensor or it could be that the O2 sensor heating element itself is bad. The code is for O2 sensor Bank 1 Sensor 2. Bank 1 means its the O2 sensor connected to the exhaust pipe that runs to cylinder #1. Sensor 2 means that it is likely the O2 sensor after the catalytic converter on the same exhaust pipe.

Ok code PO446 is your vehicles EVAPORATIVE EMISSIONS SYSTEM the most common cause is the gas cap gor left offf and someone drove the car or the cap was not fully locked it will set the code
the other causes are leaking evaporative emission plumbing from the fuel tank to the engine compartment, someone changed the fuel pump and did not seal it properly,
Failure of a emission component in the evap system
The only way to diagnost these is an OBDII scan tool and a smoke machine the light will come on when the computer does its test of the system and there is a hole as small as .020"
1/20,000 of an inch !
The light can only be turned off by a OBDII scan tool

if you found this information helpful please give me a good rating

www.aceautomotive1.com
If you need any additional help on this please contact me