Air Fuel Ratio Sensor (For Sensor 1)

4GR-FSE EMISSION CONTROL: AIR FUEL RATIO SENSOR (for Sensor 1):

ON-VEHICLE INSPECTION

1. INSPECT AIR FUEL RATIO SENSOR
(a) Disconnect the A/F sensor connector.






(b) Measure the heater resistance between terminals 1 (HT) and 2 (+B) of the sensor.
Standard resistance:
1.8 to 3.4 Ohms at 20°C (68°F)
If the result is not as specified, replace the sensor.
2. INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM
(a) Measure the voltage between the terminals of the ECM connectors.





Standard resistance:





NOTICE:
- Connect the tester leads from the backside of the connector. The connector should not be disconnected from the ECM.
- The voltage between the terminals of the ECM is kept constant regardless of the voltage of the A/F sensor.

(b) Connect Techstream to the DLC3.
(c) Turn the engine switch on (IG).
(d) Select the following menu items: Powertrain / Engine and ECT / Data List / AFS B1 S1, AFS B2 S1, O2S B1 S2 and O2S B2 S2.
(e) Warm up the A/F sensor by running the engine at 2500 rpm for approximately 2 minutes.
(f) Keep the engine speed at 2500 rpm and confirm that the displays of "AFS B1 S1" and "AFS B2 S1" are as shown in the illustration.





HINT:
- The illustration may slightly differ from the display on the Techstream.
- The waveform of the A/F sensor is displayed only on the Techstream.

(g) Check the displays of "O2S B1 S2" and "O2S B2 S2" with the engine speed at 2500 rpm.
Standard condition:
Displays show that each voltage fluctuates between 0 and 1 V.
NOTICE:
- Perform the check immediately after warming up the engine.
- If the voltage oscillation could not be verified, warm up the heated oxygen sensor again. If it is still not possible to verify, perform DTC check DTC Check / Clear.