SFI SYSTEM, Diagnostic DTC:P2195, P2196, P2197, P2198

DESCRIPTION

The A/F sensor generates a voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.

*: Value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted into a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

MONITOR DESCRIPTION

• Sensor voltage detection monitor

  Under the air-fuel ratio feedback control, if the A/F sensor voltage output indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL and sets a DTC.

  Example:

  If the A/F sensor voltage output is less than 2.8 V (very rich condition) and HO2 sensor output voltage falls from 0.59 V or more to less than 0.21 V for 5 seconds, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F sensor voltage output is more than 3.8 V (very lean condition) and HO2 sensor output voltage rises from less than 0.21 V to 0.59 V or more for 5 seconds, DTC P2195 or P2197 is set.

• Sensor current detection monitor

  A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the A/F sensor current during fuel-cut and detects any abnormal current values.

  If the A/F sensor output is 3.6 mA or more for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the A/F sensor and sets DTC P2195 or P2197 (high-side stuck). If the A/F sensor output is less than 0.78 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 or P2198 (low-side stuck).

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

1. Connect the intelligent tester to the DLC3.

2. Turn the power switch on (IG).

3. Turn the intelligent tester on.

4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.

5. Turn the power switch off and wait for at least 30 seconds.

6. Turn the power switch on (IG) and turn the intelligent tester on.

7. Put the engine in inspection mode (maintenance mode) Click here.

8. Start the engine, and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].

9. On the intelligent tester, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / All Data / Idle Fuel Cut.

10. Drive the vehicle at between 60 and 120 km/h (37 and 75 mph) for at least 10 minutes [B].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

11. With the shift lever in S position [C], accelerate the vehicle to 75 km/h (47 mph) or more by depressing the accelerator pedal for at least 10 seconds [D].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

12. Soon after performing step [D] above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal in order to execute fuel-cut control [E].

    Tech Tips

    Fuel-cut is performed when the accelerator pedal is fully released.

13. Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).

14. Repeat steps [C] through [E] above at least 3 times in one driving cycle.

15. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.

16. Read the pending DTC [F].

    Tech Tips

    
    

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

17. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

18. Input the DTC: P2195, P2196, P2197 or P2198.

19. Check the DTC judgment result.

    Tester Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
    N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips

    
    

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [F] again.

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195, P2196, P2197 OR P2198)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the tester ON.

   4. Enter the following menus: Powertrain / Engine and ECT / DTC.

   5. Read the DTCs.

      Result

      Display (DTC Output)	Proceed to
      P2195, P2196, P2197 or P2198 is output	A
      "P2195, P2196, P2197 or P2198" and "P0136, P0137, P0138, P0156, P0157 or P0158" are output	A
      P2195, P2196, P2197 or P2198 and other DTCs are output	B

      Tech Tips

      If any DTCs other than P2195, P2196, P2197 or P2198 are output, troubleshoot those DTCs first.

   
   

   B

   GO TO DTC CHART Click here

   A

2. READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF A/F SENSOR)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG) and turn the tester ON.

   3. Clear DTCs Click here.

   4. Drive the vehicle in accordance with the drive pattern described in the "CONFIRMATION DRIVING PATTERN".

   5. Enter the following menus: Powertrain / Engine and ECT / Data List / Monitor Status.

   6. Check that the status of O2S (A/FS) Monitor is Complete.

      If the status is still Incomplete, drive the vehicle according to the driving pattern again.

      Tech Tips

      
      

      • Complete indicates that the component is functioning normally.

      • Incomplete indicates that the component is malfunctioning.

   7. Enter the following menus: Powertrain / Engine and ECT / Data List / GAS AF Control / AFS Current B1S1 or AFS Current B2S1.

   8. Check the test value of the A/F sensor output current during fuel-cut.

      Result

      Test Value	Proceed to
      Within normal range (0.78 mA or more, and less than 3.6 mA)	A
      Outside normal range (Less than 0.78 mA, or 3.6 mA or more)	B

   
   

   B

   REPLACE AIR FUEL RATIO SENSOR Click here

   A

3. READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF A/F SENSOR)

   
   

   1. Put the engine in inspection mode Click here.

   2. Connect the intelligent tester to the DLC3.

   3. Turn the tester ON.

   4. Warm up the Air-Fuel Ratio (A/F) sensor at an engine speed of 2500 rpm for 90 seconds.

   5. Enter the following menus: Powertrain / Engine and ECT / Data List / GAS AF Control / Snapshot / AFS Voltage B1S1 or AFS Voltage B1S1 and Engine Speed.

   6. Check the A/F sensor voltage three times, when the engine is in each of the following conditions:

      
      

      • (1) While idling (check for at least 30 seconds)

      • (2) Fully depress the accelerator pedal and run the engine at 2500 rpm.

      • (3) Accelerator pedal released.

        Standard
        Condition A/F 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)

        Tech Tips

        For more information, see the diagrams below.

        

        Tech Tips

        
        

        • If the output voltage of the A/F sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the A/F sensor may have an open circuit. (This will also happen if the A/F sensor heater has an open circuit.)

        • If the output voltage of the A/F 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 A/F 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 A/F 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 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.

        • When the vehicle is driven:

          The output voltage of the A/F 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 A/F sensor is functioning normally.

        • The A/F 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 A/F sensor or ECM will show a constant voltage result.

   
   

   NG

   INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) Click here

   OK

4. PERFORM CONFIRMATION DRIVING PATTERN

   
   

   NEXT

5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG) and the tester ON.

   3. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.

   4. Read DTCs.

      Result

      Display (DTC Output)	Proceed to
      P2195, P2196, P2197 or P2198	A
      No output	B

   
   

   B

   PERFORM IF VEHICLE HAS RUN OUT OF FUEL IN PAST Click here

   A

6. REPLACE AIR FUEL RATIO SENSOR

   
   

   1. Replace the air fuel ratio sensor Click here.

   
   

   NEXT

7. PERFORM CONFIRMATION DRIVING PATTERN

   
   

   NEXT

8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG) and the tester ON.

   3. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.

   4. Read DTCs.

      Result

      Display (DTC Output)	Proceed to
      No output	A
      P2195, P2196, P2197 or P2198	B

   
   

   A

   END

   B

   REPLACE ECM

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

   
   

   1. Has the vehicle run out of fuel in the past?

   
   

   YES

   DTC CAUSED BY RUNNING OUT OF FUEL

   NO

   CHECK INTERMITTENT PROBLEMS

10. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

    
    

    1. Turn the power switch off.

    2. 

       Disconnect the A/F sensor connector.

    3. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Bank 1 Sensor 1 Tester Connection Condition Specified Condition 1 (HA1A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω 1 (HA1A) - 4 (A1A-) Always 10 kΩ or higher
       Bank 2 Sensor 1 Tester Connection Condition Specified Condition 1 (HA2A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω 1 (HA2A) - 4 (A2A-) Always 10 kΩ or higher

    
    

    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

11. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)

    
    

    1. Turn the power switch off.

       

    2. Disconnect the E3 and E4 ECM connectors.

    3. Measure the resistance according to the value(s) in the table below.

       Standard resistance (Check for open)
       Tester Connection Condition Specified Condition E47-1 (HA1A) - E3-5 (HA1A) Always Below 1 Ω E48-1 (HA2A) - E3-6 (HA2A) Always Below 1 Ω E3-4 (E04) - Body ground Always Below 1 Ω E4-1 (E05) - Body ground Always Below 1 Ω

       Standard resistance (Check for short)
       Tester Connection Condition Specified Condition E47-1 (HA1A) or E3-5 (HA1A) - Body ground Always 10 kΩ or higher E48-1 (HA2A) or E3-6 (HA2A) - Body ground Always 10 kΩ or higher

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

12. CHECK AIR INDUCTION SYSTEM

    
    

    1. Check the air induction system for vacuum leakage Click here.

       OK
       No leakage from air induction system.

    
    

    NG

    REPAIR OR REPLACE AIR INDUCTION SYSTEM

    OK

13. CHECK FUEL PRESSURE

    
    

    1. Check the fuel pressure Click here.

    
    

    NG

    REPAIR OR REPLACE FUEL SYSTEM (LOW PRESSURE SIDE)

    OK

14. INSPECT FUEL INJECTOR (for Port Injection)

    
    

    1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.

    
    

    NG

    REPLACE FUEL INJECTOR (for Port Injection) Click here

    OK

15. READ VALUE USING INTELLIGENT TESTER (FUEL PRESS)

    
    

    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Start the engine.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Fuel Press.

    6. While revving the engine, check that the fuel pressure fluctuates.

       Standard
       Idling
       3500 to 4500 kPa
       2500 rpm (Depress accelerator pedal fully)
       7000 to 9000 kPa

       Tech Tips

       The A/C switch and all accessory switches should be OFF, the shift lever should be in the N or P position, and the engine should be fully warmed up.

    
    

    NG

    REPAIR OR REPLACE FUEL SYSTEM FOR HIGH PRESSURE SIDE Click here

    OK

16. INSPECT FUEL INJECTOR (for Direct Injection)

    
    

    1. Inspect the fuel injector (for Direct Injection) Click here.

    
    

    NG

    REPLACE FUEL INJECTOR (for Direct Injection) Click here

    OK

17. REPLACE AIR FUEL RATIO SENSOR

    
    

    1. Replace the air fuel ratio sensor Click here.

    
    

    NEXT

18. PERFORM CONFIRMATION DRIVING PATTERN

    
    

    NEXT

19. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

    
    

    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG) and the tester ON.

    3. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.

    4. Read DTCs.

       Result

       Display (DTC Output)	Proceed to
       No output	A
       P2195, P2196, P2197 or P2198	B

    
    

    A

    END

    B

    REPLACE ECM Click here