Diagnostic Aids
WARNING: This page is about a different car, the 2000 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
After confirming DTC P0125, use scan tool to access CURRENT DATA to confirm voltage output of heated oxygen sensor No. 1. If voltage displayed on scan tool is always less than .1 volt, heated oxygen sensor No. 1 circuit may be open or shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.