DTC 18

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

DESCRIPTION

The exhaust gas sensor, which is installed on the front of the condenser, automatically changes to FRESH, FRESH / RECIRCULATION, or RECIRCULATION. The exhaust gas sensor detects CO and HC in the emission gas and transmits signals to the front light ECU (front controller).

The front light ECU (front controller) sends the read signal to the air conditioning amplifier via CAN communication line.

HINT
This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (E/G RM-IG1-2)

(a) Remove the E/G RM-IG1-2 fuse from the engine room No. 2 relay block.

(b) Measure the resistance of the fuse.

Standard resistance:





NG -- REPLACE FUSE
OK -- Continue to next step.

2. READ VALUE USING TECHSTREAM (EMISSION GAS SENSOR)

(a) Use the Data List to check if the emission gas sensor is functioning properly.

Air Conditioner





OK:

The display is as specified in the normal condition.

Result





B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

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

3. CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - BODY GROUND)





(a) Disconnect the B8 exhaust gas 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 HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - BATTERY)





(a) Disconnect the B8 exhaust gas 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 EXHAUST GAS SENSOR





(a) Remove the exhaust gas sensor Removal.

(b) After applying battery voltage between terminals 3 (IG) and 6 (E) for more than 30 seconds, measure the resistance between terminals 1 (SG) and 2 (DGS).

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

Standard resistance:





HINT
When the sensor is exposed to the exhaust gas, the resistance decreases.

NG -- REPLACE EXHAUST GAS SENSOR Removal
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (EXHAUST GAS SENSOR - FRONT LIGHT ECU)





(a) Disconnect the B8 exhaust gas sensor connector.

(b) Disconnect the B14 front light ECU connector.

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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE FRONT LIGHT ECU