HYBRID CONTROL SYSTEM, Diagnostic DTC:P0731-873

DTC Code DTC Name
P0731-873 Gear 1 Incorrect Ratio

DESCRIPTION

For a description of the hybrid vehicle transmission assembly, Click here.

Tech Tips

Although the DTC title indicates an incorrect gear ratio, this DTC relates to a malfunction of the B2 hydraulic circuit.

DTC No. INF Code DTC Detection Condition Trouble Area
P0731 873 After DTC P0868 is detected, the hybrid vehicle control ECU cannot confirm that the fluid pressure is forcibly applied to the B2 circuit.

  • Hybrid vehicle transmission assembly

  • Hybrid vehicle control ECU

  • Wire harness or connector

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0731-871 Click here.

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK DTC OUTPUT (HV)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Check if DTCs are output.

      Result
      Result Proceed to
      P0731-873 only is output. A
      Any of the following DTCs are also output. B
      DTC No. Relevant Diagnosis
      P0748-850 Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1)
      P0778-851 Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2)

    B

    GO TO DTC CHART Click here

    A

  2. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)


    1. Check the connections of the hybrid vehicle control ECU connectors.

      OK
      The connectors are connected securely and there are no contact problems.

    NG

    CONNECT SECURELY

    OK

  3. CHECK CONNECTOR CONNECTION CONDITION (TRANSMISSION WIRE CONNECTOR)


    1. Check the connection of the transmission wire connector.

      OK
      The connector is connected securely and there are no contact problems.

    NG

    CONNECT SECURELY

    OK

  4. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (SL1 SOLENOID VALVE, SL2 SOLENOID VALVE)


    1. A01GXGZE26

      Disconnect connector E58 from the hybrid vehicle control ECU.

    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition
      E58-3 (SL1+) - E58-2 (SL1-) 20°C (68°F) 5.0 to 5.6 Ω
      E58-11 (SL2+) - E58-10 (SL2-) 20°C (68°F) 5.0 to 5.6 Ω

    NG

    Click here

    OK

  5. CLEAR DTC


    1. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

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

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Clear DTCs and freeze frame data.


    NEXT

  6. SIMULATION TEST


    1. Turn the power switch on (READY).

    2. Select the following menu items : Powertrain / Hybrid Control / Active Test / Control the Shift Position.

    3. Select the following menu items: All Data / B1 Oil Pressure, B2 Oil Pressure, Line Pressure, Line Pressure Solenoid.

    4. Perform the "Control the Shift Position" active test.

      OK
      Item Condition Specified Condition
      Data List
      B1 Oil Pressure B2 Oil Pressure Line Pressure Line Pressure Solenoid
      Control the Shift Position Lo OFF ON ON OFF
      Hi ON OFF ON OFF

    5. Switch the shift position between "Lo" and "Hi" several times using the "Control the Shift Position" active test. Make sure that there is no abnormal data in the data list.

      OK
      There is no abnormal data in the data list.

      Note

      Transmission system DTCs may be set if the "Control the Shift Position" active test is canceled before it is completed.


    NG

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

    OK

  7. CHECK FOR INTERMITTENT PROBLEMS


    1. Check for intermittent problems Click here.


    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

  8. CHECK FLUID LEAKS


    1. Check for fluid leaks from the hybrid vehicle transmission assembly.

      OK
      There are no fluid leaks.

    NG

    REPAIR OR REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

  9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE)


    1. A01GWMGE19

      Disconnect the transmission wire connector and disconnect connector E58 from the hybrid vehicle control ECU.

    2. Turn the power switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      E58-19 (PB2) - Body ground Power switch on (IG) Below 1 V

      Note

      Turning the power switch on (IG) with the hybrid vehicle control ECU connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    4. Turn the power switch off.

    5. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      E58-19 (PB2) - E64-10 (PB2) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      E58-19 (PB2) or E64-10 (PB2) - Body ground and other terminals Power switch off 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here