Dtc B1418/18 Exhaust Gas Sensor Circuit

Heater & Air Conditioning System. Lexus Gs430, Gs300. Uzs190 Grs190
Air Conditioning. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT FUSE (LH-IG)

READ VALUE OF INTELLIGENT TESTER

CHECK WIRE HARNESS (EXHAUST GAS SENSOR - BODY GROUND)

CHECK WIRE HARNESS (EXHAUST GAS SENSOR - BATTERY)

INSPECT EXHAUST GAS SENSOR

CHECK WIRE HARNESS (EXHAUST GAS SENSOR - A/C AMPLIFIER)

DTC 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 emission gas and transmits signals to the A/C amplifier.

DTC No.
DTC Detection Condition
Trouble Area
B1418/18
Open or short in emission gas sensor circuit (HC, CO)
  1. Exhaust gas sensor (emission gas sensor)
  2. Harness and connector between exhaust gas sensor (emission gas sensor) and A/C amplifier
  3. A/C amplifier

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1418/18 Exhaust Gas Sensor Circuit


INSPECTION PROCEDURE

1.INSPECT FUSE (LH-IG)

  1. Remove the LH-IG fuse from the cowl side junction block LH.

  1. Measure the resistance of the fuse.

    Standard resistance:

    Tester Item
    		Condition
    		Specified Condition
    LH-IG fuse
    		Always
    		Below 1 Ω


NG
CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE
OK


2.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and push the intelligent tester main switch on.

  1. Select the item below in the Data List, and read the display on the intelligent tester.

    A/C amplifier
    Item
    		Measure Item / Display
    (Range)
    		Normal Condition
    		Diagnostic Note
    Emission Gas Sensor
    (Emiss Gas Sens)
    		Emission gas /
    Min.: 0 V, Max.: 255 V
    		Increases as the gas amount increases
    		-

    OK:
    The display is as specified in the normal condition.

    Result:
    NG
    		A
    OK (Checking from the PROBLEM SYMPTOMS TABLE)
    		B
    OK (Checking from the DTC)
    		C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER
A


3.CHECK WIRE HARNESS (EXHAUST GAS SENSOR - BODY GROUND)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1418/18 Exhaust Gas Sensor Circuit

  1. Disconnect the B10 exhaust gas sensor connector.

  1. Measure the resistance of the wire harness side connector.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    B10-6 (E) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


4.CHECK WIRE HARNESS (EXHAUST GAS SENSOR - BATTERY)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1418/18 Exhaust Gas Sensor Circuit

  1. Disconnect the B10 exhaust gas sensor connector.

  1. Measure the resistance of the wire harness side connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    B10-3 (IG) - Body ground
    		Engine switch on (IG)
    		10 to 14 V
    Engine switch off
    		Below 1 V


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


5.INSPECT EXHAUST GAS SENSOR
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1418/18 Exhaust Gas Sensor Circuit

  1. Remove the exhaust gas sensor.

  1. After applying battery voltage between terminals 3 (IG) and 6 (E) for more than 30 seconds, measure the resistance between terminals 1 (SG) and 2 (DGS).

  1. Measure the resistance of the sensor.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 (SG) - 2 (DGS)
    		10 to 35°C
    (50 to 95°F)
    		5 to 100 kΩ
    HINT:
    When the sensor is exposed to the exhaust gas, the resistance decreases.


NG
REPLACE EXHAUST GAS SENSOR
OK


6.CHECK WIRE HARNESS (EXHAUST GAS SENSOR - A/C AMPLIFIER)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System. Dtc B1418/18 Exhaust Gas Sensor Circuit

  1. Disconnect the B10 exhaust gas sensor connector.

  1. Disconnect the L52 A/C amplifier connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    B10-1 (SG) - L52-39 (SG-6)
    		Always
    		Below 1 Ω
    B10-2 (DGS) - L52-34 (DGS)
    		Always
    		Below 1 Ω
    L52-39 (SG-6) - Body ground
    		Always
    		10 kΩ or higher
    L52-34 (DGS) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER