O2S Test Result

NOTE: The O2S Test Result is not applicable to the A/F sensor and HO2S heater. These test result are checked by the Monitor Status. Refer to CHECKING MONITOR STATUS .

INTRODUCTION
The O2S Test Result (Mode 5) allows the OBD scan tool to display the test value that was used to determine whether the heated oxygen sensor (HO2S) is functioning normally or not. A problem in the HO2S can be found by comparing the test value and malfunction criterion. The O2S test result information is included under "O2S TEST RESULT" in the HO2S-related DTC sections (DTC P0136).

The ECM (PCM) monitors the HO2S. After the monitor, the ECM stores the test value. When the test value is inside the malfunction criterion, the HO2S is functioning normally. If the test value is outside the malfunction criterion, the HO2S is malfunctioning.

PROCEDURE

NOTE: Test value is cleared when the ignition switch is turned OFF.

Connect the hand-held tester to the DLC3.
Turn the ignition switch and hand-held tester.
Clear the DTC.
Run the vehicle in accordance with the HO2S monitor drive pattern. Refer to READINESS MONITOR DRIVE PATTERN .
Select from the hand-held tester menus: DIAGNOSIS, ENHANCED OBDII, MONITOR INFO and MONITOR STATUS.
Check that the HO2S monitor status (O2S MON) is either PASS or FAIL.
Select from the hand-held tester menus: DIAGNOSIS, CARB OBDII and O2S TEST RESULT.
Select the desired HO2S and press ENTER.

Fig 1: Selecting HO2S Menu Screen
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
The test value appears after the component name.
NOTE: If this vehicle is equipped with the A/F sensor, the hand-held tester will display "NO PARAMETER TO DISPLAY" when "BANK 1 - SENSOR 1" or "BANK 2 - SENSOR 1 " is selected.

Fig 2: Testing Value Menu Screen
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Some values only display a number, without a unit. Multiply the value by the unit conversion value. For example, the test value is calculated as follows:

Displayed value x unit conversion value = test value

17 x 0.3906 (%) = 6.67%

O2S TEST RESULT INFORMATION (SAMPLE)

TID	Unit Conversion	Description of Test Value	Malfunction Criterion
$81	Multiply by 0.3906 (%)	Percentage of time that HO2S voltage is less than 0.05V	60% (or more)

TID (Test Identification) is assigned to each emission-related component.

Unit Conversion is used to calculate the test value indicated on scan tools.

Compare the test value and the standard value. Test value is usually significantly higher or lower than the malfunction criterion. If the test value is very near the malfunction criterion, there is a potential malfunction is the HO2S.