On-Vehicle Inspection

WARNING: This page is about a different car, the 2008 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT AIR FUEL RATIO SENSOR
1. Disconnect the A/F sensor connector.
2. Measure the heater resistance between terminals 1 (HT) and 2 (+B) of the sensor.
  Standard resistance:
  
  1.8 to 3.4 Ω at 20°C (68°F)
  
  If the result is not as specified, replace the sensor.
  
  Fig 1: Identifying A/F Sensor Connector Terminals 1 (HT) And 2 (+B)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM

Measure the voltage between the terminals of the ECM connectors.

Fig 2: Identifying ECM Connectors Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard voltage

STANDARD VOLTAGE

Tester Connection	Condition	Specified Condition
E6-18 (A1A+) - E4-7 (E1)	Engine switch on (IG)	3.3 V
E6-17 (A1A-) - E4-7 (E1)	Engine switch on (IG)	2.9 V
E6-28 (A2A+) - E4-7 (E1)	Engine switch on (IG)	3.3 V
E6-27 (A2A-) - E4-7 (E1)	Engine switch on (IG)	2.9 V

NOTE:

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.

Connect Techstream to the DLC3.
Turn the engine switch on (IG).
Select the following menu items: Powertrain / Engine and ECT / Data List / AFS B1 S1, AFS B2 S1, O2S B1 S2 and O2S B2 S2.
Warm up the A/F sensor by running the engine at 2500 rpm for approximately 2 minutes.
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.

Fig 3: Air-Fuel Ratio Graph
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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.
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.
NOTE:
- 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 (See DTC CHECK / CLEAR ).