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Home >> Toyota >> 2023 >> GR86 Base, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (3 Of 6) >> SFI System >> DTC P050A: Cold Start Idle Control System Performance; DTC P050B: Cold Start Ignition Timing Performance [11/2021 - ] >> Procedure
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DTC P050A: Cold Start Idle Control System Performance; DTC P050B: Cold Start Ignition Timing Performance [11/2021 - ]: Procedure

  1. CHECK DTC 
    1. Turn the ignition switch to ON.
    2. Using GTS, read the DTC of [Engine].

      Powertrain > Engine Control System > Trouble Codes 

      Is DTC other than P050A displayed? (Current code)

      Result Proceed to
      Yes (Check the appropriate DTC using the "Diagnostic Trouble Code (DTC)".) A
      No B

    Result: 

    A 

    CHECK APPROPRIATE DTC 

    Refer to DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 06/2022] , or refer to DIAGNOSTIC TROUBLE CODE CHART [06/2022 - 12/2023] , or refer to DIAGNOSTIC TROUBLE CODE CHART [12/2023 - 10/2024] , or refer to DIAGNOSTIC TROUBLE CODE CHART [10/2024 - ]

    Result: 

    B 

    See step  2

  2. CHECK ENGINE OIL 
    1. Turn the ignition switch to OFF.
    2. Check the engine oil.

      Refer to PROCEDURE - Step 2

      Is there a proper amount of engine oil?

      Result Proceed to
      Yes A
      No (Replace engine oil.) B

    Result: 

    B 

    REPLACE ENGINE OIL 

    Refer to REPLACEMENT [11/2021 - 06/2022] , or refer to REPLACEMENT [06/2022 - ]

    Result: 

    A 

    See step  3

  3. CHECK EXHAUST SYSTEM 
    1. Check exhaust system parts.

      Are there holes or loose bolts on exhaust system?

      Result Proceed to
      Yes (Repair the exhaust system.) A
      No B

    Result: 

    A 

    REPAIR EXHAUST SYSTEM 

    Result: 

    B 

    See step  4

  4. CHECK AIR INTAKE SYSTEM 
    1. Check the installing condition of the air intake system.

      Are there holes, loose bolts or disconnection of hose on air intake system?

      Result Proceed to
      Yes (Repair the air intake system.) A
      No B

    Result: 

    A 

    REPAIR AIR INTAKE SYSTEM 

    Result: 

    B 

    See step  5

  5. CHECK FUEL PRESSURE 
    WARNING:

    Place "NO OPEN FLAMES" signs near the working area.

    NOTE:
    • Be careful not to spill fuel.
    • Before attaching/detaching a fuel pressure gauge, release the fuel pressure.
    1. Check the fuel pressure.

      Refer to PROCEDURE - Step 2

      Is the check result OK?

      Result Proceed to
      Yes A
      No (Check the fuel pump and fuel delivery line.) B

    Result: 

    B 

    CHECK FUEL PUMP AND FUEL DELIVERY LINE 

    Result: 

    A 

    See step  6

  6. CHECK ENGINE COOLANT TEMPERATURE SENSOR 
    1. Start the engine and warm up completely.
    2. Using GTS, read the value in [Coolant Temp.].

      Powertrain > Engine Control System > Data List 

      Tester Display
      Coolant Temp.

      Is the value of [Coolant Temp.] 75°C (167°F) or more?

      Result Proceed to
      Yes A
      No (Replace the engine coolant temperature sensor.) B

    Result: 

    B 

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    A 

    See step  7

  7. CHECK MASS AIR FLOW METER 
    1. Warm up the engine until coolant temperature is higher than 75°C (167°F).
    2. For AT models, set the select lever to "P" range or "N" range, and for MT models, place the shift lever in the neutral position.
    3. Turn the A/C switch to OFF.
    4. Turn all the accessory switches to OFF.
    5. Using GTS, read the value in [Mass Air Flow].

      Powertrain > Engine Control System > Data List 

      Tester Display
      Mass Air Flow

      Is the value of [Mass Air Flow] 2 - 5 g/s (0.26 - 0.66 lb/min)?

      Result Proceed to
      Yes A
      No (Replace the mass air flow meter.) B

    Result: 

    B 

    REPLACE MASS AIR FLOW METER 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    A 

    See step  8

  8. CHECK MASS AIR FLOW METER 
    1. Start the engine and warm up until the engine coolant temperature exceeds 75°C (167°F).
    2. For AT models, set the select lever to "P" range or "N" range, and for MT models, place the shift lever in the neutral position.
    3. Turn the A/C switch to OFF.
    4. Turn all the accessory switches to OFF.
    5. Open the front hood.
    6. Measure the ambient temperature.
    7. Using GTS, read the value in [Intake Air Temp.].

      Powertrain > Engine Control System > Data List 

      Tester Display
      Intake Air Temp.

      Subtract ambient temperature from [Intake Air Temp.]. Is the obtained value -10 - 50 [°C] (-18 - 90 °F)?

      Result Proceed to
      Yes A
      No (Check the mass air flow meter.) B

    Result: 

    B 

    CHECK MASS AIR FLOW METER 

    Refer to INSPECTION [11/2021 - ]

    Result: 

    A 

    See step  9

  9. CHECK HARNESS BETWEEN ECM AND DIRECT FUEL INJECTOR ASSEMBLY CONNECTOR (SHORT TO GROUND) 
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Disconnect the connector from direct fuel injector assembly on faulty cylinders.
    4. Measure the resistance between direct fuel injector assembly connector and engine ground on faulty cylinders.

      Connector & terminal

      #1 B16-1 - Engine ground

      #1 B16-2 - Engine ground

      #2 B17-1 - Engine ground

      #2 B17-2 - Engine ground

      #3 B18-1 - Engine ground

      #3 B18-2 - Engine ground

      #4 B19-1 - Engine ground

      #4 B19-2 - Engine ground

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the short circuit to ground in the harness between ECM and direct fuel injector assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  10

  10. CHECK HARNESS BETWEEN ECM AND DIRECT FUEL INJECTOR ASSEMBLY CONNECTOR (OPEN) 
    1. Measure the resistance of harness between ECM and direct fuel injector assembly connector on faulty cylinders.

      Connector & terminal

      B1-96 (INJ1-) - B16-1

      B1-87 (INJ1+) - B16-2

      B1-95 (INJ2-) - B17-1

      B1-86 (INJ2+) - B17-2

      B1-93 (INJ3-) - B18-1

      B1-84 (INJ3+) - B18-2

      B1-94 (INJ4-) - B19-1

      B1-85 (INJ4+) - B19-2

      Is the resistance less than 1 Ω?

      Result Proceed to
      Yes A
      No (Repair the open circuit of the harness between ECM and direct fuel injector assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  11

  11. CHECK DIRECT FUEL INJECTOR ASSEMBLY 
    1. Check the direct fuel injector assembly on faulty cylinders.

      Refer to INSPECTION [11/2021 - ]

      Is the check result OK?

      Result Proceed to
      Yes A
      No (Replace the faulty direct fuel injector assembly.) B

    Result: 

    B 

    REPLACE FAULTY DIRECT FUEL INJECTOR ASSEMBLY 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    A 

    See step  12

  12. CHECK INSTALLATION CONDITION OF VVT SENSOR AND CRANKSHAFT POSITION SENSOR 
    1. Check the installation condition of the VVT sensor and crankshaft position sensor.

      Is the VVT sensor or crankshaft position sensor loosely installed?

      Result Proceed to
      Yes (Tighten the VVT sensor or crankshaft position sensor.) A
      No B

    Result: 

    A 

    TIGHTEN THE VVT SENSOR OR CRANKSHAFT POSITION SENSOR 

    Refer to INSTALLATION [11/2021 - ]

    Refer to INSTALLATION [11/2021 - ]

    Result: 

    B 

    See step  13

  13. CHECK NO. 1 CRANK ANGLE SENSOR PLATE 
    1. Check that the No. 1 crank angle sensor plate has no deformation, cracks or other damages.

      Is the No. 1 crank angle sensor plate rusted or does it have broken teeth?

      Result Proceed to
      Yes (Replace the No. 1 crank angle sensor plate.) A
      No B

    Result: 

    A 

    REPLACE NO. 1 CRANK ANGLE SENSOR PLATE 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    B 

    See step  14

  14. CHECK INSTALLATION CONDITION OF CHAIN SUB-ASSEMBLY 
    1. Turn the crankshaft, and align the alignment mark on crank sprocket with alignment mark on cylinder block.

      Is the chain sub-assembly dislocated from its proper position?

      Result Proceed to
      Yes (Correct the installation condition of chain sub-assembly.) A
      No B

    Result: 

    A 

    CORRECT INSTALLATION CONDITION OF CHAIN SUB-ASSEMBLY 

    Refer to INSTALLATION [11/2021 - ]

    Result: 

    B 

    See step  15

  15. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT TO GROUND) 
    1. Turn the ignition switch to OFF.
    2. Disconnect the connectors from throttle body with motor assembly.
    3. Measure the resistance between the ECM connector and engine ground.

      Connector & terminal

      B1-27 (TPS5V) - Engine ground

      B1-29 (THSM) - Engine ground

      B1-29 (THSM) - B1-44 (THSSLD)

      B1-43 (THSS) - Engine ground

      B1-43 (THSS) - B1-44 (THSSLD)

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the ground short circuit of harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  16

  16. CHECK SHORT CIRCUIT INSIDE ECM 
    1. Connect the connector to ECM.
    2. Measure the resistance between throttle body with motor assembly connector and engine ground.

      Connector & terminal

      B30-4 - Engine ground

      B30-6 - Engine ground

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the ground short circuit of harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    See step  30

    Result: 

    A 

    See step  17

  17. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (OPEN) 
    1. Disconnect the connector from ECM.
    2. Measure the resistance of harness between ECM connector and throttle body with motor assembly connector.

      Connector & terminal

      B1-29 (THSM) - B30-6

      B1-30 (TPS-) - B30-3

      B1-43 (THSS) - B30-4

      Is the resistance less than 1 Ω?

      Result Proceed to
      Yes A
      No (Repair the open circuit of harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  18

  18. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (OPEN) 
    1. Connect the connector to ECM.
    2. Measure the resistance between throttle body with motor assembly connector and engine ground.

      Connector & terminal

      B30-3 - Engine ground

      Is the resistance less than 5 Ω?

      Result Proceed to
      Yes A
      No (Repair the following item.)
      • Open circuit of harness between ECM connector and engine ground
      • Poor contact of ECM connector
      		 B

    Result: 

    B 

    REPAIR RELATED PARTS 

    Result: 

    A 

    See step  19

  19. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT TO POWER SUPPLY) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage between throttle body with motor assembly connector and engine ground.

      Connector & terminal

      B30-4 - Engine ground

      B30-6 - Engine ground

      Is the voltage 5 V or higher?

      Result Proceed to
      Yes (Repair the short circuit to power supply in the harness between ECM connector and throttle body with motor assembly connector.) A
      No B

    Result: 

    A 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    B 

    See step  20

  20. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT BETWEEN LINES) 
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Measure the resistance between ECM connectors.

      Connector & terminal

      B1-27 (TPS5V) - B1-29 (THSM)

      B1-27 (TPS5V) - B1-43 (THSS)

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the short circuit between lines in harness between ECM connector and throttle body with motor assemblyconnector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  21

  21. CHECK SENSOR OUTPUT 
    1. Connect all connectors.
    2. Turn the ignition switch to ON.
    3. Using GTS, read the value in [Main-Throttle Sensor].

      Powertrain > Engine Control System > Data List 

      Tester Display
      Main-Throttle Sensor

      Is the value of [Main-Throttle Sensor] 0.81 - 0.87 V?

      Result Proceed to
      Yes A
      No (Repair the poor contact of throttle body with motor assembly connector.) B

    Result: 

    B 

    See step  32

    Result: 

    A 

    See step  22

  22. CHECK SENSOR OUTPUT 
    1. Using GTS, read the value in [Sub-Throttle Sensor].

      Powertrain > Engine Control System > Data List 

      Tester Display
      Sub-Throttle Sensor

      Is the value of [Sub-Throttle Sensor] 1.64 - 1.7 V?

      Result Proceed to
      Yes A
      No (Repair the poor contact of throttle body with motor assembly connector.) B

    Result: 

    B 

    See step  31

    Result: 

    A 

    See step  23

  23. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR 
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Disconnect the connectors from throttle body with motor assembly.
    4. Measure the resistance between ECM connector and throttle body with motor assembly connector.

      Connector & terminal

      B1-30 (TPS-) - B30-3

      B1-43 (THSS) - B30-4

      B1-29 (THSM) - B30-6

      Is the resistance less than 1 Ω?

      Result Proceed to
      Yes A
      No (Repair the open circuit of harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  24

  24. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT TO POWER SUPPLY) 
    1. Connect the connector to ECM.
    2. Turn the ignition switch to ON.
    3. Measure the voltage between throttle body with motor assembly connector and engine ground.

      Connector & terminal

      B30-1 - Engine ground

      B30-2 - Engine ground

      Is the voltage 5 V or higher?

      Result Proceed to
      Yes (Repair the short circuit to power supply in the harness between ECM connector and throttle body with motor assembly connector.) A
      No B

    Result: 

    A 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    B 

    See step  25

  25. CHECK HARNESS BETWEEN ECM AND THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT TO GROUND) 
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Measure the resistance between throttle body with motor assembly connector and engine ground.

      Connector & terminal

      B30-1 - Engine ground

      B30-2 - Engine ground

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the ground short circuit of harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  26

  26. CHECK HARNESS BETWEEN THROTTLE BODY WITH MOTOR ASSEMBLY CONNECTOR (SHORT BETWEEN LINES) 
    1. Measure the resistance between throttle body with motor assembly connectors.

      Connector & terminal

      B30-1 - B30-2

      Is the resistance 1 MΩ or more?

      Result Proceed to
      Yes A
      No (Repair the short circuit in harness between ECM connector and throttle body with motor assembly connector.) B

    Result: 

    B 

    REPAIR HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  27

  27. CHECK THROTTLE BODY WITH MOTOR ASSEMBLYL GROUND CIRCUIT (OPEN) 
    1. Measure the resistance between the ECM connector and engine ground.

      Connector & terminal

      A5-69 (GNDEG3) - Engine ground

      A5-70 (GNDEG4) - Engine ground

      A5-71 (GNDEG1) - Engine ground

      A5-72 (GNDEG2) - Engine ground

      Is the resistance less than 5 Ω?

      Result Proceed to
      Yes A
      No (Repair the following item.)
      • Open circuit of harness between ECM connector and engine ground
      • Poor contact of coupling connector
      		 B

    Result: 

    B 

    REPAIR RELATED PARTS 

    Result: 

    A 

    See step  28

  28. CHECK THROTTLE BODY WITH MOTOR ASSEMBLY 
    1. Measure the resistance between throttle body with motor assembly terminals.

      Connector & terminal

      1 - 2

      Is the resistance 0.3 - 10 Ω?

      Result Proceed to
      Yes A
      No (Replace the throttle body with motor assembly.) B

    Result: 

    B 

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    A 

    See step  29

  29. CHECK THROTTLE BODY WITH MOTOR ASSEMBLY 
    1. Move the throttle valve to the fully opened and fully closed positions with fingers.
    2. Check that the valve returns to the specified position when releasing fingers.

      Does the valve return to the specified position? (Specification: 3 mm (0.12 in) from fully closed position)

      Result Proceed to
      Yes (Repair the poor contact of ECM connector.) A
      No (Replace the throttle body with motor assembly.) B

    Result: 

    A 

    REPAIR CONNECTOR 

    Result: 

    B 

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY 

    Refer to REMOVAL [11/2021 - ]

  30. REPAIR HARNESS OR CONNECTOR 
    1. Repair the ground short circuit of harness between ECM connector and throttle body with motor assembly connector.

      Replace the ECM if defective.

      Result Proceed to
      Yes A
      No B

    Result: 

    A 

    REPLACE ECM 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    B 

    END 

  31. REPAIR CONNECTOR 
    1. Repair the poor contact of throttle body with motor assembly connector.

      Replace the throttle body with motor assembly if defective.

      Result Proceed to
      Yes A
      No B

    Result: 

    A 

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    B 

    END 

  32. REPAIR CONNECTOR 
    1. Repair the poor contact of throttle body with motor assembly connector.

      Replace the throttle body with motor assembly if defective.

      Result Proceed to
      Yes A
      No B

    Result: 

    A 

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    B 

    END 

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