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 assembly determines that the hybrid transmission assembly has seized or that there is the hybrid transmission 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 transmission malfunction

    • Seizure due to insufficient ATF

    • Damaged hybrid transmission internal components

    • Damaged transmission input damper assembly

DESCRIPTION

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

B004WYGC01
*1 Generator (MG1) *2 Input Shaft
*3 Front Planetary Sun Gear *4 Motor (MG2)
*5 Center Planetary Sun Gear *6 Center Planetary Ring Gear
*7 Rear Planetary Carrier *8 Rear Planetary Ring Gear
*9 Output Shaft *10 Rear Planetary Sun Gear
*11 Center Planetary Carrier *12 Front Planetary Ring Gear
*13 Front Planetary Carrier - -
*a Drive Force Distribution Mechanism *b Gear Shift Mechanism
*c

Transmission Input Damper

(Engine Output)

 *d to Propeller Shaft
C1 No. 1 Clutch C2 No. 2 Clutch
B1 No. 1 Brake B2 No. 2 Brake
F1 One-way Clutch - -
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 (transmission input circuit malfunction (engine system))

(1 trip detection logic)

  • Hybrid vehicle transmission assembly

  • Transmission input damper cover 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 repairs have been completed, clear the DTCs 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. 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 3 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 3 seconds or more.

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

  9. 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, perform driving pattern again.

CAUTION / NOTICE / HINT

Tech Tips


  • Engine lock or a mechanical malfunction has occurred inside the hybrid vehicle transmission assembly.

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

PROCEDURE


  1. CHECK CRANKSHAFT PULLEY REVOLUTION (P POSITION)


    1. Push the P position switch (shift position indicator).

    2. Lift up the vehicle.

    3. Turn the crankshaft pulley using hand tools to check if the crankshaft can rotate 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. Connect the GTS to the DLC3.

    2. Turn the power switch on (READY).

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

    4. Read the Data List.


      Powertrain > Motor Generator > Data List
      Tester Display
      Engine Speed
      Generator Revolution
    5. B004THSE06

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

      OK
      "MG1 Motor Revolution" is approximately 3.3 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 transmission 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 3300 rpm
      Approximately 1500 rpm Approximately 4950 rpm
      Approximately 2500 rpm Approximately 8250 rpm

    6. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for 2WD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for AWD: REPLACE HYBRID VEHICLE TRANSMISSION 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 select shift state drive (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 TRANSMISSION ASSEMBLY for 2WD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for AWD: REPLACE HYBRID VEHICLE TRANSMISSION 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 select shift state drive (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.

      Tech Tips

      If the Data List updates slowly, perform measurement after selecting only the "Engine Speed", "Generator Revolution" and "Motor Revolution" items.

      OK
      The difference between "Engine Speed" and "0.30 X Generator Revolution + 0.70 X Motor Revolution" is 500 rpm or more and it is maintained for 1 second.

    7. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE TRANSMISSION INPUT DAMPER COVER ASSEMBLY Click here

    NG

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for 2WD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for AWD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

  6. CHECK CRANKSHAFT PULLEY REVOLUTION (N POSITION)


    1. Lift up the vehicle.

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

    3. Turn the crankshaft pulley using hand tools to check if the crankshaft can rotate 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 TRANSMISSION ASSEMBLY for 2WD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here
    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY for AWD: REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

    NG

    REPAIR OR REPLACE ENGINE