The purpose of the O2S test result (mode 05) is to allow access to the results for on-board diagnostic monitoring tests of the heated oxygen sensor.

The O2S test result (mode 05) allows the OBD II scan tool to display the test values, minimum test limit and maximum test limit of the O2S. The test values are displayed after the vehicle has driven to run the O2S monitor.

When the test value is not between the minimum test limit and maximum test limit, the ECM (PCM) interprets this as a malfunction. When the O2S is not malfunction, if the difference of the test value and test limit is very small, the O2S will malfunction in near future.

Perform the following instruction to view the O2S status. Although this instruction references the Lexus/Toyota diagnostic tester, it can be checked using a generic OBD II scan tool. Refer to your for specific procedures.

NOTE: The A/F sensor test result is unable to be viewed using the O2S test result. Refer to the Checking Monitor Status to view the A/F sensor test result (See CHECKING MONITOR STATUS ).

PERFORM MONITOR DRIVE PATTERN
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch and the tester ON.
3. Clear the DTCs.
4. Run the vehicle in accordance with the drive pattern listed below. Do not turn the ignition switch OFF.
  NOTE: The test results will be lost if the ignition switch is turned OFF.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

O2S Test Result

Use the Manual With the Right Hardware

When to See a Mechanic