DTC 18

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1418/18: Exhaust Gas Sensor Circuit
B1418/18 - Exhaust Gas Sensor Circuit

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.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (LH-IG)

(a) Remove the LH-IG fuse from the cowl side junction block LH.

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

Standard resistance:





NG -- REPLACE FUSE (LH-IG)
OK -- Continue to next step.

2. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) Select the item below in the Data List, and read the display on the Techstream.

Data List / Air Conditioner:





OK:

The display is as specified in the normal condition column.

Result:





B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C -- REPLACE AIR CONDITIONING AMPLIFIER
A -- Continue to next step.

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

(a) Disconnect the smog ventilation sensor connector.





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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

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

(a) Disconnect the smog ventilation sensor connector.





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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. INSPECT SMOG VENTILATION SENSOR

(a) Remove the smog ventilation sensor.





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

(c) 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 kOhms to 40 kOhms.

NG -- REPLACE SMOG VENTILATION SENSOR
OK -- Continue to next step.

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

(a) Disconnect the smog ventilation sensor.





(b) Disconnect the A/C amplifier connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER