Inspection Procedure

HINT:

Techstream only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the ACTIVE TEST. The Control the Injection Volume for A/F sensor function can help to determine whether the Air Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation using a Techstream.

1. Connect a Techstream to the DLC3.
2. Start the engine and turn the tester ON.
3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
4. Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
5. Perform the Control the Injection Volume for A/F sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
6. Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.

HINT:

• The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
• Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard 

Case	A/F Sensor (Sensor 1) Output Voltage			HO2 Sensor (Sensor 2) Output Voltage			Main Suspected Trouble Area
1	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
	Output Voltage	More than 3.35 V Less than 3.0 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage	More than 0.55 V Less than 0.4 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	A/F sensor A/F sensor heater A/F sensor circuit
	Output Voltage	Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage	More than 0.55 V Less than 0.4 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	HO2 sensor HO2 sensor heater HO2 sensor circuit
	Output Voltage	More than 3.35 V Less than 3.0 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage	Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume	+25% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Fuel Injector Fuel pressure Gas leak from exhaust system (Air fuel ratio extremely rich or lean)
	Output Voltage	Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage	Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

• Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors
• To display the graph, select the following menu items on the tester: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor / A/F Control System / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, then press the graph button on the Data List view.

HINT:

Read freeze frame data using a Techstream. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430) 
   1. Connect a Techstream to the DLC3.
   2. Turn the ignition switch ON and turn the tester ON.
   3. Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
   4. Read DTCs and write them down.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      P0420 and/or P0430	A
      P0420 and/or P0430 and other DTCs	B

      HINT:

      If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.

   B: GO TO DTC CHART  (See DIAGNOSTIC TROUBLE CODE CHART  )

   A: Go To Next Step 

2. PERFORM ACTIVE TEST USING TECHSTREAM (A/F CONTROL) 
   1. Connect a Techstream to the DLC3.
   2. Start the engine and turn the tester ON.
   3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
   4. Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
   5. Perform the Control the Injection Volume for A/F sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
   6. Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.

      HINT:

      • The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
      • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

      Standard 

      STANDARD VOLTAGE
      
      

      Tester Display (Sensor)	Injection Volumes	Status	Voltages
      AFS B1S1 or AF SB2S1 (A/F)	+25 %	Rich	Less than 3.0
      AFS B1S1 or AFS B2S1 (A/F)	-12.5%	Lean	More than 3.35
      O2S B1S2 or O2S B2S2 (HO2)	+25 %	Rich	More than 0.55
      O2S B1S2 or O2S B2S2 (HO2)	-12.5%	Lean	Less than 0.4

      Result 

      RESULT REFERENCE
      
      

      Status AFS B1S1 or AFS B2S1	Status O2S B1S2 or O2S B2S2	A/F Condition and A/F and HO2 Sensors Conditions	Misfires	Main Suspected Trouble Areas	Proceed To
      Lean/Rich	Lean/Rich	Normal	-	Three-Way Catalytic Converter (TWC) Gas leak from exhaust system	A
      Lean	Lean/Rich	A/F sensor malfunction	-	A/F sensor	B
      Rich	Lean/Rich	A/F sensor malfunction	-	A/F sensor
      Lean/Rich	Lean	HO2 sensor malfunction	-	HO2 sensor Gas leak from exhaust system	C
      Lean/Rich	Rich	HO2 sensor malfunction	-	HO2 sensor Gas leak from exhaust system
      Lean	Lean	Actual air-fuel ratio lean	May occur	Extremely rich or lean actual air-fuel ratio Gas leak from exhaust system	A
      Rich	Rich	Actual air-fuel ratio rich	-	Extremely rich or lean actual air-fuel ratio Gas leak from exhaust system
      Lean: During Control the Injection Volume for A/F sensor, the A/F sensor output voltage (AFS) is consistently more than 3.35 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V. Rich: During Control the Injection Volume for A/F sensor, the AFS is consistently less than 3.0 V, and the O2S is consistently more than 0.55 V. Lean/Rich: During Control the Injection Volume for A/ F sensor of the ACTIVE TEST, the output voltage of the HO2 sensor alternates correctly.

   B: CHECK AND REPLACE AIR FUEL RATIO SENSOR 

   C: CHECK AND REPLACE HEATED OXYGEN SENSOR, AND CHECK AND REPAIR EXHAUST GAS LEAK 

   A: Go To Next Step 

3. CHECK FOR EXHAUST GAS LEAK 

   OK: No gas leak. 

   NG: REPAIR OR REPLACE EXHAUST GAS LEAK POINT 

   OK: Go to Next Step 

4. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430) 
   1. According to the DTCs output in Step  1 (CHECK ANY OTHER DTCS OUTPUT), proceed to the next step, referring to the table below.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      P0420	A
      P0430	B
      P0420 and P0430	A and B

   A: Go to step 5 

   B: Go to step   6

5. REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY RH 
   1. Replace the exhaust manifold sub-assembly RH (See REMOVAL ).

   NEXT: REPLACE FRONT EXHAUST PIPE ASSEMBLY  (See INSTALLATION )

6. REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY LH 
   1. Replace the exhaust manifold sub-assembly LH (See REMOVAL ).

   NEXT: REPLACE NO. 2 FRONT EXHAUST PIPE ASSEMBLY  (See INSTALLATION )