Diagnostic Aids

After confirming DTC P0125, use Toyota hand-held tester or scan tool to access CURRENT DATA to read output voltage for A/F sensors. ECM maintains a fixed voltage of 3.3 volts at AFR+ and AFL+ terminals on ECM, and 3.0 volts at AFR- and AFL- terminal on ECM. It is impossible to confirm A/F sensor output voltage without using Toyota hand-held tester or scan tool. A/F sensor output voltage on scan tool is displayed at one fifth the voltage of that displayed on a Toyota hand-held tester. Using hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.