Diagnostic Aids
WARNING: This page is about a different car, the 2002 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
After confirming DTC P0125, use Toyota hand-held tester or scan tool to access CURRENT DATA to read output voltage for heated oxygen sensor on each exhaust manifold (bank No. 1 sensor No. 1 and bank No. 2 sensor No. 1). If output voltage is always less than .1 volt, heated oxygen sensor circuit may be open or shorted. Using hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.