Up to 08/2009

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1461/61: Emission Gas NOx Sensor Circuit
B1461/61 - Emission Gas NOx Sensor Circuit

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).





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 (NOx) 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:





C -- REPLACE A/C AMPLIFIER

B -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures
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 a negative (-) lead to terminal 6 (E).

(c) 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 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