HYBRID CONTROL SYSTEM, Diagnostic DTC:P28077F

DTC Code DTC Name
P28077F Pressure Control Solenoid "G" Actuator Stuck Off

DTC SUMMARY


  1. MALFUNCTION DESCRIPTION

    This indicates that a mechanical malfunction has occurred inside the hybrid transmission.

    The cause of this DTC may be one of the following.


    • Valve stuck inside transmission valve body (jamming due to foreign matter, etc.)

    • Damage inside transmission due to above valve becoming stuck

    • Oil pump motor lock (jamming due to foreign matter, etc.)

DESCRIPTION

Based on signals from the motor resolver and transmission revolution sensor (SP2), the actual gear is detected.

If the detected gear is different than the commanded gear, the hybrid vehicle control ECU assembly detects related mechanical problems in the shift solenoid valves, transmission valve body assembly and hybrid vehicle transmission assembly.

In addition, when the oil pump with motor assembly does not operate, line pressure is not generated. As a result, this DTC may be output.

In the normal condition, the output shaft speed is within the speed difference permissible range of the motor speed in accordance with the gear ratio of each gear position commanded by the hybrid vehicle control ECU assembly.

Note

This DTC is output based on the mechanical gear position inside the transmission. Therefore, check the "Current Calculated Gear Position" Data List item.

Tech Tips

Actual gear when a malfunction occurs in solenoid (SL4) valve (without fail-safe control):
Hybrid vehicle control ECU assembly commanded gear 1st 2nd 3rd 4th
Actual gear during SL4 stuck ON malfunction 1st N*1 3rd N*1
Actual gear during SL4 stuck OFF malfunction*2 1st 2nd 3rd 4th

*1: Neutral

*2: Vehicle does not move with shift position in R.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
P28077F Pressure Control Solenoid "G" Actuator Stuck Off

Drive the vehicle with shift position in D, M or R.

Either condition is met:


  • When the hybrid vehicle control ECU assembly commands the transmission to shift to 1st, 2nd or 4th, it is actually in neutral*.

    *: The difference between the expected input speed from "transmission output speed and gear ratio of each gear position" and the actual input speed (motor speed) is large.

    (2-trip detection logic)

  • When the hybrid vehicle control ECU assembly commands the transmission to shift to reverse, it is actually in neutral*.

    *: The difference between the expected input speed from "transmission output speed and gear ratio of each gear position" and the actual input speed (motor speed) is large.

    (2-trip detection logic)

  • Solenoid (SC1) valve

  • Solenoid (SC2) valve

  • Solenoid (SL1) valve

  • Solenoid (SL2) valve

  • Solenoid (SL3) valve

  • Solenoid (SL4) valve

  • Solenoid (SLT) valve

  • Transmission valve body assembly

  • Hybrid vehicle transmission assembly

  • Oil with motor pump assembly

  • Wire harness or connector

  • OIL PMP relay

  • Fusible link (OIL PMP)

 Comes on

Master Warning Light:

Comes on
Related Data List
DTC No. Data List
P28077F

  • Current Calculated Gear Position

  • Output Shaft Revolution (Transmission)

  • Motor Revolution
Related Active Test
DTC No. Active Test
P28077F

  • Solenoid (SLT)*1

  • Solenoid (SL1)*1

  • Solenoid (SL2)*1

  • Solenoid (SL3)*1

  • Solenoid (SL4)*1

  • Solenoid (SC1)*1

  • Solenoid (SC2)*1

  • Control the Transmission Oil Pump*2
*1: When the solenoid is malfunctioning, it may not turn on and off according to commands from the GTS.
*2: When the motor is malfunctioning, a deviation may occur between the GTS motor speed command and the actual motor speed.

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 (READY).

  6. With the brake pedal depressed, move the shift lever to select shift position R.

  7. Drive the vehicle in reverse for 5 m (16 ft.) or more with the accelerator pedal depressed slightly.

  8. After stopping the vehicle, move the shift lever to select shift position D.

  9. Accelerate until the value of the "Current Calculated Gear Position" Data List item changes to "4th", and then release the accelerator slightly and continue driving for a few seconds.

    CAUTION:

    Strictly observe posted speed limits, traffic laws and road conditions when performing this test.

    Tech Tips


    • It is easy to enter 4th gear by first accelerating to 80 km/h (50 mph), slowly releasing the accelerator pedal until it is fully released, and then accelerating again.

    • If the Data List updates slowly, perform measurement after selecting only the "Current Calculated Gear Position", "Output Shaft Revolution (Transmission)", "Motor Revolution", "Vehicle Speed" and "Accelerator Position" items.

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

  11. 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 the normal judgment procedure again.

PROCEDURE


  1. CHECK DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Transmission / Trouble Codes.


      Powertrain > Transmission > Trouble Codes

    5. Read the DTCs using the GTS.

      Result
      Result Proceed to
      Only DTC P28077F or one of the following P07457F, P076A71, P07757F, P07957F, P08CC71, P27137F or P279762 are output A
      Other DTCs are output B

    6. Turn the power switch off.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK OIL PUMP MOTOR CIRCUIT

    Click here

    Result
    Proceed to
    NEXT

    NEXT

  3. CHECK SOLENOID VALVE CIRCUIT

    Click here

    Tech Tips

    If the "Solenoid Valve Circuit" inspection results are normal, perform the next step.

    Result
    Proceed to
    NEXT

    NEXT

    REPAIR OR REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here