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Home >> Toyota >> 2017 >> Yaris iA Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Troubleshooting (2 Of 2) >> SFI System >> No. 12 Lack/Loss Of Power-Acceleration/Cruise >> Procedure

No. 12 Lack/Loss Of Power-Acceleration/Cruise: Procedure

  1. VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING 
    1. Does the engine idle rough?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    PERFORM THE SYMPTOM TROUBLESHOOTING "NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE". 

    1. Refer to NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE 

    Result:  1

    No 

    See step  2

  2. VERIFY IF MALFUNCTION CAUSE IS OVERHEATING 
    1. Access the Engine coolant temperature PID using the Techstream.

      Refer to ON-BOARD DIAGNOSTIC TEST

      NOTE:
      • While performing this step, always operate the vehicle in a safe and lawful manner.
      • When the Techstream is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the Techstream using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
    2. Is the Engine coolant temperature PID value less than 116°C {241°F} during driving?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    PERFORM THE SYMPTOM TROUBLESHOOTING "NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING". 

    1. Refer to NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING 

    Result:  1

    No 

    See step  3

  3. VERIFY DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM 
    1. Retrieve the ECM DTC using the Techstream.

      Refer to ON-BOARD DIAGNOSTIC TEST

    2. Is the DTC P229900 present?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    GO TO THE APPLICABLE DTC INSPECTION. (DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM.) 

    1. Refer to DTC P229900: BRAKE PEDAL POSITION/ACCELERATOR PEDAL POSITION INCOMPATIBLE

    Result:  1

    No 

    See step  4

  4. VERIFY ECM DTC 
    1. Retrieve any DTCs using the Techstream.

      Refer to ON-BOARD DIAGNOSTIC TEST

    2. Are any DTCs present?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    GO TO THE APPLICABLE DTC INSPECTION. 

    1. Refer to DIAGNOSTIC TROUBLE CODE CHART

    Result:  1

    No 

    See step  5

  5. VERIFY CURRENT INPUT SIGNAL STATUS 
    NOTE:
    • While performing this step, always operate the vehicle in a safe and lawful manner.
    • When the Techstream is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the Techstream using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
    1. Access the following PIDs using the Techstream:

      Refer to ON-BOARD DIAGNOSTIC TEST

      1. Accelerator pedal position sensor 1
      2. Accelerator pedal position sensor 2
      3. Clutch Pedal Position Switch/Neutral Switch Circuit (MTX)
      4. Engine coolant temperature
      5. Fuel pressure sensor
      6. Intake Air Temperature
      7. Mass Air Flow
      8. Manifold absolute pressure sensor
      9. Relative Throttle Position
      10. Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 1)
      11. Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 2)
      12. Short term fuel trim 1
      13. Long term fuel trim 1
    2. Do the PIDs indicate the correct values under the malfunction condition?

      Refer to INSPECTION

      Result

      Result
      Yes
      No

    Result:  2

    No 

    PIDS ARE NOT AS SPECIFIED: 

    1. Accelerator pedal position sensor 1, Accelerator pedal position sensor 2 PIDs are not as specified:
      1. Inspect the APP sensor.

        Refer to INSPECTION

    2. Clutch Pedal Position Switch/Neutral Switch Circuit PID is not as specified: (MTX)
      1. Inspect the neutral switch.

        Refer to INSPECTION

    3. Engine coolant temperature PID is not as specified:
      1. Inspect the ECT sensor No. 1.

        Refer to INSPECTION

    4. Fuel pressure sensor PID is not as specified:
      1. Inspect the fuel pressure sensor.

        Refer to INSPECTION

    5. Intake Air Temperature PID is not as specified:
      1. Inspect the IAT sensor No. 1.

        Refer to INSPECTION

    6. Mass Air Flow PID is not as specified:
      1. Inspect the MAF sensor.

        Refer to INSPECTION

    7. Manifold absolute pressure sensor PID is not as specified:
      1. Inspect the MAP sensor.

        Refer to INSPECTION

    8. Relative Throttle Position PID is not as specified:
      1. Inspect the TP sensor.

        Refer to INSPECTION

    9. Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 1), Short term fuel trim 1, Long term fuel trim 1 PIDs are not as specified:
      1. Inspect the A/F sensor.

        Refer to INSPECTION

    10. Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 2) PID is not as specified:
      1. Inspect the HO2S.

        Refer to INSPECTION

    11. Repair or replace the malfunctioning part according to the inspection results.
      1. If the malfunction remains:
        • Inspect communication error between TCM and ECM. (ATX)
          • Repair or replace the malfunctioning part according to the inspection results if necessary.
        • Perform the "INTERMITTENT CONCERN TROUBLESHOOTING" procedure.

          Refer to HOW TO PROCEED WITH TROUBLESHOOTING

    Result:  1

    Yes 

    See step  6

  6. INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION 
    1. Perform the Electronic Control Throttle Operation Inspection.

      Refer to ON-VEHICLE INSPECTION

    2. Does the drive-by-wire control system work properly?

      Result

      Result
      Yes
      No

    Result:  2

    No 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    Yes 

    See step  7

  7. INSPECT FUEL INJECTOR OPERATION 
    1. Perform the Fuel Injector Operation Inspection.

      Refer to ON-VEHICLE INSPECTION

    2. Do the fuel injectors operate properly?

      Result

      Result
      Yes
      No

    Result:  2

    No 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    Yes 

    See step  8

  8. INSPECT PURGE CONTROL SYSTEM OPERATION 
    1. Perform the Purge Control System Inspection.

      Refer to ON-VEHICLE INSPECTION

    2. Does the purge VSV work properly?

      Result

      Result
      Yes
      No

    Result:  2

    No 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    Yes 

    See step  9

  9. INSPECT FUEL SYSTEM FOR FUEL LEAKAGE 
    1. Inspect for fuel leakage in the fuel line.
    2. Is there any leakage?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    No 

    See step  10

  10. INSPECT RELATED PART CONDITION 
    1. Inspect the following:
      1. Fuel quality (proper octane, contamination, winter/summer blend)
      2. Air leakage or restriction in intake-air system
      3. Air cleaner restricted or dirty
      4. Vacuum leakage
      5. Clutch slippage (MTX)
      6. Brake dragging
      7. Tire air pressure
      8. CKP sensor and CMP sensor
        • Installation condition

          Refer to REMOVAL

          Refer to REMOVAL

        • Damaged trigger wheel and camshaft
    2. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    SERVICE IF NECESSARY. 

    1. Repeat this step.

    Result:  1

    No 

    See step  11

  11. INSPECT FUEL PRESSURE (HIGH-SIDE) 
    1. Start the engine and warm it up completely.
    2. Access the Fuel pressure sensor PID using the Techstream at idle.

      Refer to ON-BOARD DIAGNOSTIC TEST

    3. Is the Fuel pressure sensor PID value approx. 3 MPa {31 kgf/cm2 , 435 psi}?

      Result

      Result
      Yes
      No

    Result:  1

    No 

    See step  21

    Result:  2

    Yes 

    See step  13

  12. INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND 
    1. Switch the ignition off.
    2. Disconnect the high pressure fuel pump and ECM connectors.
    3. Inspect for continuity between high pressure fuel pump terminal C15-1 (wiring harness-side) and body ground.
    4. Is there continuity?

      Result

      Result
      Yes
      No

    Result:  1

    No 

    REPLACE THE HIGH PRESSURE FUEL PUMP. 

    1. Refer to REMOVAL

    Result:  2

    Yes 

    REFER TO THE WIRING DIAGRAM AND VERIFY WHETHER OR NOT THERE IS A COMMON CONNECTOR BETWEEN HIGH PRESSURE FUEL PUMP TERMINAL C15-1 AND ECM TERMINAL C27-30. 

    If there is a common connector: 

    • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
    • Repair or replace the malfunctioning part.

    If there is no common connector: 

    • Repair or replace the wiring harness which has a short to ground.

    If the malfunction remains: 

    • Replace the ECM. (damage to driver in ECM)

      Refer to REMOVAL

  13. INSPECT FUEL PRESSURE (LOW-SIDE) 
    1. Connect the fuel pressure gauge between fuel pump and high pressure fuel pump.
    2. Measure the low side fuel pressure.

      Refer to ON-VEHICLE INSPECTION

    3. Is the low side fuel pressure within specification?

      Specification

      405-485 kPa {4.13-4.94 kgf/cm2 , 58.8-70.3 psi}

      Result

      Result
      Yes
      No

    Result:  2

    No 

    INSPECT THE FOLLOWING: 

    1. Fuel line restriction
    2. Fuel filter clogged
      1. If there is any malfunction:
        • Repair or replace the malfunctioning part according to the inspection results.
      2. If there is no malfunction:
        • Replace the fuel pump unit.

          Refer to REMOVAL

    Result:  1

    Yes 

    See step  14

  14. INSPECT THROTTLE BODY FOR CLOGGING 
    1. Visually inspect the throttle valve.

      Refer to REMOVAL

    2. Is any foreign matter adhering around the throttle valve?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    CLEAN THE THROTTLE VALVE. 

    Result:  1

    No 

    See step  15

  15. INSPECT ENGINE COMPRESSION 
    1. Measure the compression pressure for each cylinder.

      Refer to INSPECTION

    2. Are compression pressures within specification?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    See step  18

    Result:  1

    No 

    See step  16

  16. INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION 
    1. Perform the Hydraulic Variable Valve Timing Control System Operation Inspection.

      Refer to ON-VEHICLE INSPECTION

    2. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    No 

    See step  17

  17. INSPECT FOR MALFUNCTION DUE TO DEVIATED VALVE TIMING 
    1. Inspect the valve timing (timing chain installation condition).

      Refer to REMOVAL

    2. Is the valve timing normal?

      Result

      Result
      Yes
      No

    Result:  1

    No 

    ADJUST THE VALVE TIMING TO THE CORRECT TIMING. 

    Result:  2

    Yes 

    INSPECT FOR THE FOLLOWING ENGINE INTERNAL PARTS: 

    1. Cylinder
    2. Piston ring
    3. Intake valve
    4. Exhaust valve
    5. Such as cylinder head gasket
      1. If there is any malfunction:
        • Repair or replace the malfunctioning part according to the inspection results.
  18. VERIFY SPARK PLUG CONDITION 
    1. Inspect the spark plug condition.

      Refer to INSPECTION

    2. Is the spark plug wet, covered with carbon or grayish white?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    SPARK PLUG IS WET OR COVERED WITH CARBON / GRAYISH WHITE 

    1. Spark plug is wet or covered with carbon:
      1. Perform the Spark Test.

        Refer to ON-VEHICLE INSPECTION

        • Repair or replace the malfunctioning part according to the inspection results.
    2. Spark plug is grayish white:
      1. Inspect the fuel injector for restriction.
        • Repair or replace the malfunctioning part according to the inspection results.

    Result:  1

    No 

    See step  19

  19. INSPECT EXHAUST SYSTEM FOR RESTRICTION 
    1. Inspect for restriction in the exhaust system and the TWC.
    2. Is there any restriction?

      Result

      Result
      Yes
      No

    Result:  2

    Yes 

    REPAIR OR REPLACE THE MALFUNCTIONING PART ACCORDING TO THE INSPECTION RESULTS. 

    Result:  1

    No 

    See step  20

  20. INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR INJECTOR DRIVER (ECM INTEGRATED) 
    1. Inspect the PCV valve.

      Refer to INSPECTION

    2. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result:  1

    No 

    INJECTOR DRIVER MALFUNCTION. 

    1. Injector driver malfunction.
      1. Replace the ECM.

        Refer to REMOVAL

    2. If the problem remains, overhaul the engine.

    Result:  2

    Yes 

    REPLACE THE PCV VALVE. 

    1. Refer to REMOVAL
  21. LOWER THAN 3 MPa {31 kgf/cm2, 435 psi}: 
    1. Lower than 3 MPa {31 kgf/cm2 , 435 psi}:
      1. Inspect the following:
        • Fuel leakage at the fuel line and fuel injector
        • Fuel pump
        • Fuel pressure sensor

          Refer to INSPECTION

        • High pressure fuel pump

          Refer to INSPECTION

      2. If there is any malfunction:
        • Repair or replace the malfunctioning part according to the inspection results.
      3. If there is no malfunction:
        • Go to the next step.
    2. Higher than 3 MPa {31 kgf/cm2 , 435 psi}:
      1. Go to the next step.

      Result

      Proceed to
      NEXT

    Result:  1

    NEXT 

    See step  12

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