AIR CONDITIONING SYSTEM, Diagnostic DTC:B1418/18

DTC Code DTC Name
B1418/18 Exhaust Gas Sensor Circuit

DESCRIPTION

The exhaust gas sensor, which is installed on the front of the condenser, automatically changes to FRESH, FRESH / RECIRCULATION, or RECIRCULATION. The exhaust gas sensor detects CO and HC in the emission gas and transmits signals to the front controller.

The front controller sends the read signal to the air conditioning amplifier via the CAN communication line.

Tech Tips

This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.

DTC Code DTC Detection Condition Trouble Area
B1418/18 Open or short in emission gas sensor circuit (HC, CO)

  • Exhaust gas sensor (smog ventilation sensor)

  • Harness or connector between exhaust gas sensor (smog ventilation sensor) and front controller

  • Front controller

  • CAN communication line

  • Air conditioning amplifier

WIRING DIAGRAM

A01GZJXE09

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT FUSE (D-IG1-2)


    1. Remove the D-IG1-2 fuse from the main body ECU (driver side junction block).

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      D-IG1-2 fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  2. READ VALUE USING INTELLIGENT TESTER (EMISSION GAS SENSOR)


    1. Use the Data List to check if the emission gas sensor is functioning properly.

      Air conditioner
      Tester Display Measurement Item / Range Normal Condition Diagnostic Note
      Emission Gas Sensor

      Emission gas sensor /

      Min.: 0, Max.: 255

      		 Decreases as the gas amount increases -
      OK
      The display is as specified in the normal condition.

    NG

    CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - BODY GROUND) Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER Click here

  3. CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - BODY GROUND)

    A01H11WE01

    1. Disconnect the B8 exhaust gas sensor connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      B8-6 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - BATTERY)

    A01H11WE02

    1. Disconnect the B8 exhaust gas sensor connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      B8-3 (IG) - Body ground Power switch ON (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT EXHAUST GAS SENSOR

    A01GZ14E01

    1. Remove the exhaust gas sensor Click here.

    2. After applying battery voltage between terminals 3 (IG) and 6 (E) for more than 30 seconds, measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      1 (SG) - 2 (DGS)

      10 to 35°C

      (50 to 95°F)

      		 1.5 to 240 kΩ

      Tech Tips

      When the sensor is exposed to the exhaust gas, the resistance decreases.


    NG

    REPLACE EXHAUST GAS SENSOR Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - FRONT CONTROLLER)

    A01GXCME03

    1. Disconnect the B8 exhaust gas sensor connector.

    2. Disconnect the B14 front controller connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      B8-1 (SG) - B14-9 (DGSE) Always Below 1 Ω
      B8-2 (DGS) - B14-11 (DGS)
      B14-9 (DGSE) - Body ground Always 10 kΩ or higher
      B14-11 (DGS) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE FRONT CONTROLLER