DTC P1C77-79: Engine Failed To Start Mechanical Linkage Failure: Notes

1. - 

Outline of diagnosis: 

Cranking occurred during driving, but the engine does not rotate (fault of transaxle input system (engine system))

(1 trip detection logic)

Trouble symptom: 

• Reduced output power
• A driving range is limited
• Engine always stopped

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CRANK PULLEY ROTATION (P POSITION)  .
   1. Check that the shift is placed in P position.
   2. Lift up the vehicle at all wheels.
   3. Rotate the crank pulley clockwise by hand and check if the crank shaft rotates.
      CAUTION: Turn to READY ON during inspection. Be sure to check for IG OFF before inspection to prevent the engine from starting.
      NOTE: It is occasionally difficult to rotate the crank pulley due to resistance with compression in the engine. Therefore check whether or not the rotation can be done (locked/unlocked) by applying appropriate torque by hand (a torque that can rotate the crank pulley in normal engine condition of the same type).

   Does the crank pulley rotate?

   Yes  : Go to  2.

   No  : Go to  5.

2. CHECK ENGINE RACING  .
   1. Using the Subaru Select Monitor, read and record the following DTCs and freeze frame data. Ref. to ENGINE (DIAGNOSTICS) (H4DO (HEV))>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to ENGINE (DIAGNOSTICS) (H4DO (HEV))>FREEZE FRAME DATA . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>FREEZE FRAME DATA .
      • Engine
      • P-HEV Hybrid Powertrain Control
   2. Using the Subaru Select Monitor, perform the following clear memory. Ref. to COMMON (DIAG)>CLEAR MEMORY .
      • Engine
      • P-HEV Hybrid Powertrain Control
   3. Check that the shift is placed in P position.
   4. Set the vehicle to Inspection Mode for measuring Exhaust Gas. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>WORK SUPPORT>OPERATION>SERVICE MODE .
   5. Turn to READY ON.
   6. Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
      • Engine Speed
      • Generator Revolution
   7. With the READY light illuminating, depress the accelerator pedal for 10 seconds.
   8. Check the revolution speed.
   NOTE:

   • Reference value

     Item	Engine speed	Generator revolution speed
     Condition	Approx. 1000 rpm	Approx. 3400 rpm
     	Approx. 1500 rpm	Approx. 5100 rpm
     	Approx. 2000 rpm	Approx. 6800 rpm

   • Alignment chart

   Courtesy of SUBARU OF AMERICA, INC.

   Does [Generator Revolution] become approximately 3.4 times of [Engine Speed]? (See the reference values and alignment chart above)

   NOTE: When the engine is not racing and DTC P314779 ([Transmission (Shaft) Mechanical Linkage Failure]) is displayed as a result of reading DTC using the Subaru Select Monitor, or when the generator turns but the engine cranking does not occur, replace Transmission assembly. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>TRANSMISSION ASSEMBLY .

   Yes  : Go to  3.

   No  : Replace Transmission assembly and Damper (with torque limiter). Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>TRANSMISSION ASSEMBLY . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .

3. CHECK CREEP RUNNING  .
   1. Turn to READY ON.
   2. Depress the brake pedal and shift to D position. Then, release the brake pedal.
   3. Check the tires for smooth rotation (check whether creep running is possible).

   Do the tires rotate? (Is creep running possible?)

   Yes  : Go to  4.

   No  : Replace Transmission assembly and Damper (with torque limiter). Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>TRANSMISSION ASSEMBLY . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .

4. CHECK ENGINE SPEED AT ACCELERATION  .
   1. Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
      • Engine Speed
      • Generator Revolution
      • Motor Revolution
   2. Shift to D position.
   3. Fully accelerate from the vehicle speed at 10 km/h (6.2 MPH) or more.
      CAUTION: Check the safety around the vehicle and perform the test.
   4. Check the revolution speed.

   Does the difference (absolute value) of 500 r/min or more between "[Engine Speed]" and "0.29 x [Generator Revolution] + 0.17 x [Motor Revolution]" continue for one second or more?

   Yes  : Replace Transmission assembly and Damper (with torque limiter). Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>TRANSMISSION ASSEMBLY . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .

   No  : Replace Damper (with torque limiter). Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .

5. CHECK CRANK PULLEY ROTATION (N POSITION)  .
   1. Lift up the vehicle at all wheels.
   2. Depress the brake pedal and shift the select lever to N position.
   3. Rotate the crank pulley clockwise by hand and check if the crank shaft rotates.
      CAUTION: Turn to READY ON during inspection. Be sure to check for IG OFF before inspection to prevent the engine from starting.
      NOTE: It is occasionally difficult to rotate the crank pulley due to resistance with compression in the engine. Therefore check whether or not the rotation can be done (locked/unlocked) by applying appropriate torque by hand (a torque that can rotate the crank pulley in normal engine condition of the same type).

   Does the crank pulley rotate?

   Yes  : Replace Transmission assembly and Damper (with torque limiter). Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>TRANSMISSION ASSEMBLY . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .

   No  : Replace Damper (with torque limiter), and repair or replace the engine. Ref. to SPECIFICATION . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TH2A)>FLYWHEEL .