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 sensor, Heated Oxygen 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 the Techstream.

1. Connect the Techstream to the DLC3.
2. Start the engine.
3. Turn the Techstream on.
4. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
6. Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
7. Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS B1 S1 and O2S B1 S2) displayed on the Techstream.

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.

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
2	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injector Fuel pressure Gas leak from exhaust system (Air fuel ratio extremely rich or lean)

• Following the Control the Injection Volume for air fuel ratio sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
• To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2; then press the graph button on the Data List view.

HINT:

• Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
• A low air fuel ratio sensor voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
• A high air fuel ratio sensor voltage could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195 OR P2196) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
   5. Read DTCs.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      P2195 or P2196	A
      P2195 or P2196 and other DTCs	B

      HINT:

      If any DTCs other than P2195 and P2196 are output, troubleshoot those DTCs first.

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

   A: Go to next step 

2. READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Clear the DTCs (See DTC CHECK / CLEAR ).
   5. Allow the vehicle to drive in accordance with the drive pattern described in the Confirmation Driving Pattern.
   6. Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor.
   7. Check that the status of O2 Sensor is Complete.

      If the status is still Incomplete, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

   8. Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RANGE B1 S1.
   9. Check the test value of the air fuel ratio sensor output current during fuel-cut.

   Result 

   RESULT REFERENCE
   
   

   Result	Proceed to
   Within normal range (1.0 mA or more, and less than 3.6 mA)	A
   Outside normal range (Less than 1.0 mA, or 3.6 mA or more)	B

   B: Go to step  19

   A: Go to next step 

3. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR) 
   1. Connect the Techstream to the DLC3.
   2. Start the engine.
   3. Turn the Techstream on.
   4. Warm up the air-fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
   5. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS B1 S1 and Engine Speed, then press the Record button.
   6. Check the air fuel ratio sensor voltage three times, when the engine is in each of the following conditions:
      1. While idling (check for at least 30 seconds)
      2. At an engine speed of approximately 2500 rpm (without any sudden changes in engine speed)
      3. Raise the engine speed to 4000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed.

   Standard 

   STANDARD REFERENCE
   
   

   Condition	Air Fuel Ratio Sensor Voltage Variation	Reference
   (1) and (2)	Changes at approximately 3.3 V	Between 3.1 V and 3.5 V
   (3)	Increases to 3.8 V or more	This occurs during engine deceleration (when fuel-cut performed)

   HINT:

   For more information, see the below.

   Fig 1: Air Fuel Ratio Sensor Voltage Diagram

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   • If the output voltage of the air fuel ratio sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have an open circuit. (This will also happen if the air fuel ratio sensor heater has an open circuit.)
   • If the output voltage of the air fuel ratio sensor remains at either approximately 3.8 V or more, or 2.8 V or less (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have a short circuit.
   • The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the air fuel ratio sensor output voltage.
   • The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 10 mph (16 km/h) to allow the ECM to learn the closed throttle valve position.
   • When the vehicle is driven:

   The output voltage of the air fuel ratio sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The air fuel ratio sensor is functioning normally.

   • The air fuel ratio sensor is a current output element; therefore, the current is converted into a voltage inside the ECM. Measuring the voltage at the connectors of the air fuel ratio sensor or ECM will show a constant voltage result.

   NG: Go to step  10

   OK: Go to next step 

4. PERFORM CONFIRMATION DRIVING PATTERN 
5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
   5. Read DTCs.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      P2195 or P2196	A
      No output	B

   B: Go to step  9

   A: Go to next step 

6. REPLACE AIR FUEL RATIO SENSOR 
   1. Replace the air fuel ratio sensor (See AIR FUEL RATIO SENSOR ).
7. PERFORM CONFIRMATION DRIVING PATTERN 
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
   5. Read DTCs.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      No output	A
      P2195 or P2196	B

   B: REPLACE ECM  (See ECM )

   A: Go to next step 

9. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST 

   NO: CHECK FOR INTERMITTENT PROBLEMS  (See CHECK FOR INTERMITTENT PROBLEMS )

   YES: DTC CAUSED BY RUNNING OUT OF FUEL 

10. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)  (See WIRING DIAGRAM )

    NG: REPLACE AIR FUEL RATIO SENSOR  (See AIR FUEL RATIO SENSOR )

    OK: Go to next step 

11. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM) 
    1. Disconnect the air fuel ratio sensor connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Open) 

       RESISTANCE REFERENCE
       
       

       Tester Connection	Condition	Specified Condition
       B16-1 (HA1A) - B29-109 (HA1A)	Always	Below 1 Ω
       B16-3 (A1A+) - B29-112 (A1A+)
       B16-4 (A1A-) - B29-113 (A1A-)

       Standard Resistance (Check for Short) 

       RESISTANCE REFERENCE
       
       

       Tester Connection	Condition	Specified Condition
       B16-1 (HA1A) or B29-109 (HA1A) - Body ground	Always	10 kΩ or higher
       B16-3 (A1A+) or B29-112 (A1A+) - Body ground
       B16-4 (A1A-) or B29-113 (A1A-) - Body ground

    4. Reconnect the air fuel ratio sensor connector.
    5. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR ECM) 

    Fig 2: Identifying Air Fuel Ratio Sensor Connector Terminal

    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

12. CHECK INTAKE SYSTEM 
    1. Check the intake system for vacuum leaks (See INTAKE SYSTEM ).

       OK: 

       No leaks in intake system  .

    NG: REPAIR OR REPLACE INTAKE SYSTEM  (See INTAKE SYSTEM )

    OK: Go to next step 

13. CHECK FUEL PRESSURE 
    1. Check the fuel pressure (See ON-VEHICLE INSPECTION ).

    NG: REPAIR OR REPLACE FUEL SYSTEM 

    OK: Go to next step 

14. INSPECT FUEL INJECTOR 
    1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (See INSPECTION ).

    NG: REPLACE FUEL INJECTOR  (See FUEL INJECTOR )

    OK: Go to next step 

15. REPLACE AIR FUEL RATIO SENSOR 
    1. Replace the air fuel ratio sensor (See AIR FUEL RATIO SENSOR ).
16. PERFORM CONFIRMATION DRIVING PATTERN 
17. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
    5. Read DTCs.

       Result 

       RESULT REFERENCE
       
       

       Result	Proceed to
       No output	A
       P2195 or P2196	B

    B: REPLACE ECM  (See ECM )

    A: Go to next step 

18. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST 

    NO: CHECK FOR INTERMITTENT PROBLEMS  (See CHECK FOR INTERMITTENT PROBLEMS )

    YES: DTC CAUSED BY RUNNING OUT OF FUEL 

19. REPLACE AIR FUEL RATIO SENSOR 
    1. Replace the air fuel ratio sensor (See AIR FUEL RATIO SENSOR ).
20. PERFORM CONFIRMATION DRIVING PATTERN 
21. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read DTCs.

       Result 

       RESULT REFERENCE
       
       

       Result	Proceed to
       No output	A
       P2195 or P2196 (Air fuel ratio sensor pending DTCs)	B

    B: REPLACE ECM  (See ECM )

    A: END