Check Engine Light On

Ten days before my smog check, my 98 Camry check engine is on. Checked everything under the hood, looks all ok. Went to Auto Zone and get my self a code scanner. Auto Zone rent you one for 150 and if you return within 30 days they return your memory.

Plug in the scanner, it gave me code P0125 and P1135. I cleared the code with the scanner and the light went off for a few miles and then comes back. So the problem is real.

Search through the net and found the O2 sensor most likely is the cause. Get a multimeter and measured it, it is bad. So I went around and found again Auto Zone has the lowest price. Order one and replaced the sensor. Then cleared the code with code scan. It might clear itself given enough time but I can't wait. Since then the check engine light never come back and I passed the smog test.