Toyota Repair: Check Engine Light, air fuel ratio, fuel mileage

Question
I have a 2000 4Runner - V6. The check engine light came on. The codes are P0125 and P1135. I'm not sure what they mean. Can you tell me what they mean and are they something that has to be addressed right away or can I continue to drive the vehicle without doing any damage. Thank you

Answer
The P1135 code is an air/fuel ratio sensor malfunction code bank one sensor one( translation) the air/fuel ratio sensor located just in front of the catalityc converter needs to be replaced on the right side. The PO125 is diectly related and can be ignored, replacing the sensor fixes both. It should be replaced as soon as possible,although
there is almost no noticeable driveability issue, it can affect fuel mileage to some degree and may cause the engine to run too lean/rich. So replace it when you can but there's no need to park it until it can be replaced.