HYBRID CONTROL SYSTEM, Diagnostic DTC:P1C7779

DTC Code DTC Name
P1C7779 Engine Failed to Start Mechanical Linkage Failure

DTC SUMMARY


  1. MALFUNCTION DESCRIPTION

    These DTCs are stored when the hybrid vehicle control ECU determines that the hybrid transaxle assembly has seized or that there is the hybrid transaxle assembly malfunction in the drivetrain. The cause of this malfunction may be one of the following:


      Engine malfunction

    • Seizure due to insufficient engine oil

    • Seizure due to insufficient coolant

    • Damaged engine


      Hybrid transaxle malfunction

    • Seizure due to insufficient ATF

    • Damaged hybrid transaxle internal components

    • Damaged transmission input damper assembly

    • Damaged one-way clutch assembly

DESCRIPTION

The hybrid vehicle transaxle assembly consists of the planetary gear unit, generator (MG1) and motor (MG2). The planetary gear unit uses a planetary gear to split the engine output into mechanical power and electrical power in accordance with driving requests when the vehicle is being driven or the HV battery is being charged. When accelerating, motor (MG2) assists engine output by increasing vehicle driving force. Motor (MG2) also converts braking energy, which would otherwise be consumed in the form of heat during braking, into electrical energy. This recovered energy is stored in the HV battery. Generator (MG1) supplies power, which is used for charging the HV battery or driving motor (MG2), and also regulates the amount of electricity being generated. In addition, generator (MG1) is used as a starter motor to start the engine.

If the hybrid vehicle control ECU detects that the engine or transaxle gear has seized, the hybrid vehicle control ECU will perform fail-safe control. Also, if a substance or object is preventing the engine or transaxle internal components from rotating, the hybrid vehicle control ECU will perform fail-safe control.

A003KXJE02
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
P1C7779 Engine Failed to Start Mechanical Linkage Failure

The engine does not start even though it is being cranked while driving (transaxle input circuit malfunction (engine system))

(1 trip detection logic)

  • Hybrid vehicle transaxle assembly

  • Transmission input damper assembly

  • One-way clutch assembly

  • Engine

 Does not come on

Master Warning Light:

Comes on
Related Data List
DTC No. Data List
P1C7779

  • Engine Speed

  • Generator Revolution

  • Motor Revolution

  • Target Generator Torque

  • Generator Torque

CONFIRMATION DRIVING PATTERN

Tech Tips

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Click here


  1. Connect the GTS to the DLC3.

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

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

  4. Turn the power switch off and wait for 2 minutes or more.

  5. Turn the power switch on (IG) and turn the GTS on.

  6. Turn the power switch on (READY).

  7. Press the HV/EV mode switch to enter HV drive mode.

  8. While driving the vehicle at a speed of 20 km/h (12 mph) or more in EV mode, depress the accelerator pedal to start the engine, and drive the vehicle for 2 seconds or more.*1

    *1: When the HV system is normal, the engine starts when the accelerator pedal is depressed halfway or more. If the HV system is malfunctioning, the engine may not start. Even in this case, drive the vehicle at a speed of 20 km/h (12 mph) or more in EV mode for 2 seconds or more.

  9. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.

  10. Check the DTC judgment result.

    Tech Tips


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

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

    • If the judgment result shows INCOMPLETE or N/A, perform driving pattern again.

CAUTION / NOTICE / HINT

Tech Tips

If this DTC is output, the engine or hybrid transaxle assembly may have seized. Before performing this inspection, check the engine oil, hybrid transaxle fluid, coolant (for Engine) and coolant (for Inverter) levels.

PROCEDURE


  1. CHECK CRANKSHAFT PULLEY REVOLUTION (P POSITION)


    1. Check that park (P) is selected.

    2. Lift the vehicle.

    3. Manually turn the crankshaft pulley clockwise to check if the crankshaft rotates smoothly.

      CAUTION:

      Do not turn the power switch on (READY) while performing this inspection. Be sure to turn the power switch off before performing this inspection, to prevent the engine from starting.

      Note

      Engine compression causes resistance when turning the crankshaft pulley. Check if the crankshaft rotates smoothly (or if it is locked) by manually applying sufficient torque to turn the crankshaft pulley. The torque required to turn the crankshaft pulley should be the same as for a known good vehicle of the same type.

      OK
      The crankshaft rotates smoothly.

    4. Lower the vehicle.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK CRANKSHAFT PULLEY REVOLUTION (N POSITION) Click here

    OK

  2. CLEAR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

    4. Read and record the DTCs and freeze frame data.


      Powertrain > Hybrid Control > Trouble Codes

    5. Enter the following menus: Powertrain / Engine / Trouble Codes.

    6. Read and record the DTCs and freeze frame data.


      Powertrain > Engine > Trouble Codes

    7. Clear the DTCs and freeze frame data.


      Powertrain > Hybrid Control > Clear DTCs
      Powertrain > Engine > Clear DTCs

    8. Turn the power switch off.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK ENGINE RACING


    1. Check that park (P) is selected.

    2. Connect the GTS to the DLC3.

    3. Put the engine in maintenance mode.

    4. Turn the power switch on (READY).

    5. Enter the following menus: Powertrain / Motor Generator Control / Data List / Generator Revolution, Engine Speed.

    6. Read the Data List.


      Powertrain > Motor Generator > Data List
      Tester Display
      Engine Speed
      Generator Revolution
    7. A003N1IC02
      *a Generator (MG1)
      *b Engine
      *c Motor (MG2)
      *d Malfunction
      *e Normal

      While the READY indicator is on, depress the accelerator pedal for 10 seconds.

      OK
      "MG1 Motor Revolution" is approximately 3.6 times "Engine Speed".

      Tech Tips


      • If the engine does not race and DTC P314779 (Transmission system) is output or generator (MG1) operates but the engine does not crank, replace the hybrid vehicle transaxle assembly.

      • Refer to the graph for Data List confirmation of "Generator Revolution" and " Engine Speed".

      Data List Engine Speed MG1 Motor Revolution
      Reference Value Approximately 1000 rpm Approximately 3600 rpm
      Approximately 1500 rpm Approximately 5400 rpm
      Approximately 2500 rpm Approximately 9000 rpm

    8. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here

    OK

  4. CHECK CREEP MOVEMENT


    1. Turn the power switch on (READY).

    2. Depress the brake pedal, move the shift lever to D, and release the brake pedal.

      OK
      The wheels turn (the vehicle creeps forward).

    3. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here

    OK

  5. INSPECT ENGINE SPEED


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (READY).

    3. Enter the following menus: Powertrain / Motor Generator Control / Data List / Engine Speed, Motor Revolution, Generator Revolution.

    4. Read the Data List.


      Powertrain > Motor Generator > Data List
      Tester Display
      Engine Speed
      Motor Revolution
      Generator Revolution

    5. Move the shift lever to D.

    6. Fully depress the accelerator pedal when the vehicle speed is 10 km/h (6 mph) or more.

      Note

      Perform this test only in an appropriate safe location, in accordance with all local laws.

      OK
      The difference between "Engine Speed" and "0.28 X Generator Revolution + 0.19 X Motor Revolution" is below 500 rpm and it is maintained for 1 second.

      Tech Tips

      If the transaxle gear is normal, the following formula is true.

      Engine Speed = 0.28 X Generator Revolution + 0.19 X Motor Revolution

    7. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here

    NG

    REPLACE TRANSMISSION INPUT DAMPER ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here

  6. CHECK CRANKSHAFT PULLEY REVOLUTION (N POSITION)


    1. Lift the vehicle.

    2. Depress the brake pedal and move the shift lever to select neutral (N).

    3. Manually turn the crankshaft pulley clockwise to check if the crankshaft rotates smoothly.

      CAUTION:

      Do not turn the power switch on (READY) while performing this inspection. Be sure to turn the power switch off before performing this inspection, to prevent the engine from starting.

      Note

      Engine compression causes resistance when turning the crankshaft pulley. Check if the crankshaft rotates smoothly (or if it is locked) by manually applying sufficient torque to turn the crankshaft pulley. The torque required to turn the crankshaft pulley should be the same as for a known good vehicle of the same type.

      OK
      The crankshaft rotates smoothly.

    4. Lower the vehicle.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY AND ONE-WAY CLUTCH ASSEMBLY Click here

    NG

    REPLACE ONE-WAY CLUTCH ASSEMBLY AND REPAIR OR REPLACE ENGINE Click here