Lexus IS250 · Service Manual HEATER & AIR CONDITIONING SYSTEM

B1461/61

Diagnostic trouble codes

DESCRIPTION

The smog ventilation sensor detects NOx in the emission gas and transmits signals to the A/C amplifier. Based on the signals, the A/C amplifier performs automatic air inlet control (FRESH, FRESH / RECIRCULATION, or RECIRCULATION mode).
DTC No.
 DTC Detection Condition
 Trouble Area
B1461/61
 Open or short in emission gas NOx sensor circuit
  1. Smog ventilation sensor (emission gas NOx sensor)
  2. Harness and connector between smog ventilation sensor (emission gas NOx sensor) and A/C amplifier
  3. A/C amplifier

WIRING DIAGRAM

E116914E01

INSPECTION PROCEDURE


1. INSPECT FUSE (LH-IG)

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

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


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



NG
REPLACE FUSE (LH-IG)
OK


2. READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

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

  1. Allow exhaust gas (NOx) to travel to the sensing portion of the smog ventilation sensor.

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

Data List / Air Conditioner: 
Item
 Measure Item / Display (Range)
 Normal Condition
 Diagnostic Note
Emission Gas Sensor
(Emiss Gas Sens)
 Emission gas NOx sensor / 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 the PROBLEM SYMPTOMS TABLE)
 B
OK (When troubleshooting according to the DTC)
 C



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER
A


3. CHECK WIRE HARNESS (SMOG VENTILATION SENSOR - BODY GROUND)

  1. E107005E08
    Disconnect the smog ventilation sensor connector.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    B11-6 (E) - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4. CHECK WIRE HARNESS (SMOG VENTILATION SENSOR - BATTERY)

  1. E107005E09
    Disconnect the smog ventilation sensor connector.

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

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    B11-3 (IG) - Body ground
    		 Engine switch on (IG)
    		 10 to 14 V
    Engine switch off
    		 Below 1 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5. INSPECT SMOG VENTILATION SENSOR

  1. E107006E08
    Remove the smog ventilation sensor.

  1. Apply battery voltage between terminals 3 (IG) and 6 (E).

  1. Allow exhaust gas (NOx) to travel to the sensing portion of the smog ventilation sensor, and measure the resistance between terminals 1 (SG) and 4 (DGS1).

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

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



 NG
REPLACE SMOG VENTILATION SENSOR
OK


6. CHECK WIRE HARNESS (SMOG VENTILATION SENSOR - A/C AMPLIFIER)

  1. E107007E06
    Disconnect the exhaust gas sensor connector.

  1. Disconnect the A/C amplifier connector.

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

    Standard resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    B11-1 (SG) - J58-39 (SG-6)
    		 Always
    		 Below 1 Ω
    B11-4 (DGS1) - J58-33 (DGS1)
    		 Always
    		 Below 1 Ω
    J58-39 (SG-6) - Body ground
    		 Always
    		 10 kΩ or higher
    J58-33 (DGS1) - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER


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