2011 Lexus IS FFACTORY OEM SERVICE PROCEDURE

On-Vehicle Inspection

  1. INSPECT AIR FUEL RATIO SENSOR (for Bank 1) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 1: Identifying Air Fuel Ratio Sensor Connector
      GTY131460Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (HA1A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      1 (HA1A) - 4 (A1A-) Always 10 kΩ or higher

      If the result is not as specified, replace the air fuel ratio sensor.

  2. INSPECT AIR FUEL RATIO SENSOR (for Bank 2) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 2: Identifying Air Fuel Ratio Sensor Connector
      GTY131458Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (HA2A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      1 (HA2A) - 4 (A2A-) Always 10 kΩ or higher

      If the result is not as specified, replace the air fuel ratio sensor.

  3. INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM 

    HINT: 

    Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine whether the air-fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning.

    The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation using the Techstream.

    1. Connect the Techstream to the DLC3.
    2. Start the engine and turn the Techstream ON.
    3. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
    4. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.
    5. Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
    6. Monitor the output voltages of the air-fuel ratio and heated oxygen sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the Techstream.

    HINT: 

    • The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
    • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
    Tester Display (Sensor) Injection Volume Status Voltage
    AFS B1 S1 or AFS B2 S1
    (A/F)    		 +25% Rich Less than 3.0 V
    AFS B1 S1 or AFS B2 S1
    (A/F)    		 -12.5% Lean More than 3.35 V
    O2S B1 S2 or O2S B2 S2
    (HO2)    		 +25% Rich More than 0.55 V
    O2S B1 S2 or O2S B2 S2
    (HO2)    		 -12.5% Lean Less than 0.4 V
    NOTE:

    The air-fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.

    Case A/F Sensor (Sensor 1) Output Voltage HO2 Sensor (Sensor 2) Output Voltage Main Suspected Trouble Area
    1
    GTY102471GTY143186Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002
    Chapter Navigation
    Return to Chapter: On-Vehicle Inspection
    Factory Service Tools

    Use the Manual With the Right Hardware

    Pair factory procedures with proven DIY tools so the instructions are easier to execute.

    Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

    Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

    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.