Do a search for the codes and it will give you the info you need to troubleshoot. I found it had a lot of useful information, but there is a vast array of helpful individuals who will probably chime in soon.

 

You said you replaced the 02 sensor. As in singular? Not an expert but there's a recurring theme I have seen on here multiple times over.
1-02 sensors are a wear item. They're usually good for about 100 k's. If you replace one, replace them all around that time.
2-Toyota's dont always work well with Bosch so make sure you buy Denso only.
3- Watch for knock offs. Apparently there's a lot of counterfeit stuff out there now.

Read posts 13 and 15 here.
And if you do figure it out, dont be one of those guys that never comes back and leaves another dead end thread. Be one of the good guys and come back with how you fixed it.

Code PO125

Does anyone know what causes this code? And how to resolve?

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