B1418/18

DESCRIPTION

The smog ventilation sensor, which is installed on the front of the condenser, is used for automatic air inlet control. 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 and connector between smog ventilation sensor (emission gas sensor) and A/C amplifier A/C amplifier

WIRING DIAGRAM

INSPECTION PROCEDURE

1. INSPECT FUSE (LH-IG)

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

2. 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.

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

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

4. 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 / Min.: 0 V, Max.: 255 V	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. 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
   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. Disconnect the smog ventilation sensor connector.

2. 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. Remove the smog ventilation sensor.

2. Apply battery voltage between terminals 3 (IG) and 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.
   

   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. Disconnect the smog ventilation sensor.

2. Disconnect the A/C amplifier connector.

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

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   B11-1 (SG) - J58-39 (SG-6)	Always	Below 1 Ω
   B11-2 (DGS) - J58-34 (DGS)	Always	Below 1 Ω
   J58-39 (SG-6) - Body ground	Always	10 kΩ or higher
   J58-34 (DGS) - Body ground	Always	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE AIR CONDITIONING AMPLIFIER