AIR CONDITIONING SYSTEM, Diagnostic DTC:B1418/18

DTC Code DTC Name
B1418/18 Exhaust Gas Sensor Circuit

DESCRIPTION

The smog ventilation sensor is installed on the front of the condenser to control automatic air inlet. This sensor detects CO and HC in the emission gas and transmits signals to the A/C amplifier.

DTC No. DTC Detection Condition Trouble Area
B1418/18 Open or short in smog ventilation sensor circuit (HC, CO)

  • Smog ventilation sensor (emission gas sensor)

  • Harness or connector between smog ventilation sensor (emission gas sensor) and A/C amplifier

  • A/C amplifier

WIRING DIAGRAM

A01NFKIE04

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the intelligent tester on.

    4. Allow exhaust gas (HC, CO) to travel to the sensing portion of the smog ventilation sensor.

    5. Enter the following menus: Body / Air Conditioner / Data List.

    6. Check the value(s) by referring to the table below.

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

      Emission gas (HC, CO) /

      Min.: 0

      Max.: 255

      		 Smog ventilation sensor value increases as gas amount increases -
      OK
      The display is as specified in the Normal Condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    REPLACE A/C AMPLIFIER Click here

    A

  2. CHECK HARNESS AND CONNECTOR (SMOG VENTILATION SENSOR - BODY GROUND)


    1. A01ND7VE17
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Smog Ventilation Sensor)

      Disconnect the smog ventilation sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B2-6 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (SMOG VENTILATION SENSOR - BATTERY)


    1. A01ND7VE18
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Smog Ventilation Sensor)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B2-3 (IG) - Body ground Power switch on (IG) 11 to 14 V
      B2-3 (IG) - Body ground Power switch off Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT SMOG VENTILATION SENSOR


    1. A01NGPBE10
      Text in Illustration
      *1

      Component without harness connected

      (Smog Ventilation Sensor)

      Remove the smog ventilation sensor.

    2. Connect a battery positive (+) lead to terminal 3 (IG) and a negative (-) lead to terminal 6 (E).

    3. Allow exhaust gas (HC, CO) to travel to the sensing portion of the smog ventilation sensor, and measure the resistance between terminals 1 (SG) and 2 (DGS).

      OK
      When the sensor is exposed to the exhaust gas, the resistance increases.

      Tech Tips

      The resistance before blowing exhaust gas is 10 kΩ to 40 kΩ.


    NG

    REPLACE SMOG VENTILATION SENSOR Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (SMOG VENTILATION SENSOR - A/C AMPLIFIER)


    1. A01NDH4E23

      Disconnect the A/C amplifier connector.

    2. A01ND7VE19
      Text in Illustration
      *1

      Front view of wire harness connector

      (to A/C Amplifier)
      *2

      Front view of wire harness connector

      (to Smog Ventilation Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B2-1 (SG) - F50-13 (SG-2) Always Below 1 Ω
      B2-2 (DGS) - F50-6 (DGS) Always Below 1 Ω
      F50-13 (SG-2) - Body ground Always 10 kΩ or higher
      F50-6 (DGS) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE A/C AMPLIFIER Click here