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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 477 (Air Conditioning System - Diagnosis) >> Circuit Inspection >> DTC B1418/18 Exhaust Gas Sensor Circuit (HC, CO) >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

In case of using the LEXUS hand- held tester, start the inspection step 1 and in case of not using the LEXUS hand-held tester, start from step  2.

  1. Check exhaust gas sensor using LEXUS hand- held tester. 

    PREPARATION: 

    Connect the LEXUS hand-held tester to the DLC3.

    CHECK: 

    Check the exhaust gas sensor using DATA LIST.

    1. OK : Check and replace A/C ECU. 
    2. NG : Go to next step. 
  2. Check voltage between terminals DGS and SG-1 of A/C ECU connector. 

    PREPARATION: 

    Remove A/C ECU with connectors still connected.

    CHECK: 

    1. Turn ignition switch to ON.
    2. After continuing to turn ignition switch ON for more than 30 seconds, check voltage between terminals DGS and SG-1 of A/C ECU connector at the temperature.

    OK: 

    Voltage: 

    1.0- 4.5 V at 10 - 35 °C (50 - 95 °F) 

    Fig 1: Identifying Terminals DGS And SG-1 Of A/C ECU Connector
    G03376736Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    When the sensor is exposed to the exhaust gas, the voltage goes down.

    1. NG : Go to step 3. 
    2. OK : Proceed to next circuit inspection shown on problem symptom table (See  PROBLEM SYMPTOMS TABLE  ). However, if DTC B1418/18 is displayed, check and replace A/C ECU. 
  3. Check exhaust gas sensor resistance 

    PREPARATION: 

    Remove the exhaust gas sensor (See SMOG VENTILATION SENSOR ).

    CHECK: 

    1. Connect positive (+) lead from the battery to the terminal 3 and negative (-) lead to terminal 5.
    2. After keeping to apply battery voltage between terminals 3 and 5 for more than 30 seconds, measure resistance between terminals 1 and 2.

    OK: 

    Resistance: 

    5 - 100 kΩ V at 10 - 35 °C (50 - 95 °F) 

    Fig 2: Identifying Exhaust Gas Sensor Resistance
    G03376737Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT:

    When the sensor is exposed to the exhaust gas, the resistance goes down.

    1. NG : Replace exhaust gas sensor. 
    2. OK : Go to next step. 
  4. Check harness and connector between A/C ECU and exhaust gas sensor (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    1. NG : Repair or replace harness for connector. 
    2. OK : Check and replace A/C ECU.