Inspection Procedure

HINT:

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.

• Connect the Techstream to the DLC3.
• Start the engine and turn the tester ON.
• Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
• Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
• 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).
• 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 AFS B2S1 (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

  NOTE: The Air Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.
  VOLTAGE OUTPUT DELAY
  
  

  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

• 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.
• 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.

HINT:

• DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.
• A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
• A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.
• 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 P2A00 AND/OR P2A03) 
   1. Connect a Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the tester ON.
   4. Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
   5. Read DTCs.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      P2A00 and/or P2A03	A
      P2A00 and/or P2A03 and other DTCs	B

      HINT:

      If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.

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

   A: Go to next step 

2. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)  (See INSPECTION PROCEDURE  )

   NG: REPLACE AIR FUEL RATIO SENSOR  (See REMOVAL )

   OK: Go to Next Step 

3. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)  (See INSPECTION PROCEDURE  )

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: Go to Next Step 

4. PERFORM CONFIRMATION DRIVING PATTERN 
5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03) 
   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.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      P2A00 and/or P2A03	A
      No output	B

   B: CHECK FOR INTERMITTENT PROBLEMS 

   A: Go to next step 

6. REPLACE AIR FUEL RATIO SENSOR 

   Replace the air fuel ratio sensor (See REMOVAL ).

7. PERFORM CONFIRMATION DRIVING PATTERN 
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03) 
   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.

      Result 

      RESULT REFERENCE
      
      

      Display (DTC Output)	Proceed To
      No output	A
      P2A00 and/or P2A03	B

   B: CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO  (REFER TO DTC P0171 PROCEDURE )

   A: END