Lexus IS250 · Service Manual ENGINE

ON-VEHICLE INSPECTION

Inspection


INSPECT AIR FUEL RATIO SENSOR

  1. Disconnect the A/F sensor connector.

  1. A104022E01
    Measure the heater resistance between terminals 1 (HT) and 2 (+B) of the sensor.

    Standard resistance:
    1.8 to 3.4 Ω at 20°C (68°F)

    If the result is not as specified, replace the sensor.


INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM

  1. Measure the voltage between the terminals of the ECM connectors.

    A108550E05

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    E6-18 (A1A+) - E4-7 (E1)
    		 Engine switch on (IG)
    		 3.3 V
    E6-17 (A1A-) - E4-7 (E1)
    		 Engine switch on (IG)
    		 2.9 V
    E6-28 (A2A+) - E4-7 (E1)
    		 Engine switch on (IG)
    		 3.3 V
    E6-27 (A2A-) - E4-7 (E1)
    		 Engine switch on (IG)
    		 2.9 V

    NOTICE:
    1. Connect the tester leads from the backside of the connector. The connector should not be disconnected from the ECM.
    2. The voltage between the terminals of the ECM is kept constant regardless of the voltage of the A/F sensor.

  1. A127529E01
    Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Select the following menus: Powertrain / Engine / Data List / A/FS B1 S1, A/FS B2 S1, O2S B1 S2 and O2S B2 S2.

  1. Warm up the A/F sensor by running the engine at 2, 500 rpm for approximately 2 minutes.

  1. Keep the engine speed at 2,500 rpm and confirm that the displays of "A/FS B1 S1" and "A/FS B2 S1" are as shown in the illustration.

    A108547E01

    HINT:
    1. The illustration may slightly differ from the display on the intelligent tester.
    2. The waveform of the A/F sensor is displayed only on the intelligent tester.

  1. Check the displays of "O2S B1 S2" and "O2S B2 S2" with the engine speed at 2,500 rpm.

    Standard condition:
    Displays show that each voltage fluctuates between 0 and 1 V.

    NOTICE:
    1. Perform the check immediately after warming up the engine.
    2. If the voltage oscillation could not be verified, warm up the heated oxygen sensor again. If it is still not possible to verify, perform DTC check (Click here).

← COMPONENTSREMOVAL →