B1418

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1418/18: Exhaust Gas Sensor Circuit
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.





WIRING DIAGRAM





INSPECTION PROCEDURE

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

PROCEDURE

1. 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) Enter the following menus: Body Electrical / Air Conditioner / Data List.

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

Air Conditioner





OK:

The display is as specified in the normal condition column.

Result:





B -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

C -- REPLACE A/C AMPLIFIER Removal
A -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (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:





Text in Illustration





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

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

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





Standard Voltage:





Text in Illustration





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

4. INSPECT SMOG VENTILATION SENSOR

(a) Remove the smog ventilation sensor.





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

Text in Illustration





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

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

(a) Disconnect the A/C amplifier connector.





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





Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE A/C AMPLIFIER Removal