Some 2009-2012 Toyota RAV4 and 2010-2011 Camry vehicles equipped with a 2AR-FE (non-PZEV) engine may exhibit a MIL on with DTC P0138 (oxygen sensor circuit high voltage Bank 1 sensor 2). This condition may be caused by incorrect air-fuel ratio sensor response. The ECM logic has been modified to reduce this possibility. The ECM should not be replaced as part of the repair. Toyota recommends using the GR8 battery diagnostic station to maintain battery voltage.
First check for any exhaust leaks. If no exhaust leaks are found, connect Techstream and check for the DTC. If DTC P0138 is stored, start the engine and turn Techstream on. Warm up the engine at an engine speed of 2500 rpm for about 90 seconds. Enter the following menus: Powertrain – engine and ECT – active test – control the injection volume for A/F sensor. Perform the active test operation with the engine idling. Press the right or left button to change the fuel injection volume. Monitor the output voltage of the HO2 sensor displayed on the Techstream. Compare the monitored voltages to the following:
TESTER DISPLAY (SENSOR) INJ. VOL STATUS VOLTAGE
O2S B1S2 (HO2)
+25% ............ RICH ......Higher than 0.55V
-25% ............. LEAN .....Below 0.4V
If data does not meet this criteria, update the ECM to the latest available calibration.
