HYBRID CONTROL SYSTEM, Diagnostic DTC:P0731-871

DTC Code DTC Name
P0731-871 Gear 1 Incorrect Ratio

DESCRIPTION

The hybrid vehicle control ECU uses the B1 and B2 brakes in the hybrid vehicle transmission assembly to switch between low and high gear.

Shifting control is performed using the line pressure circuit, B1 circuit, and B2 circuit. The hybrid vehicle control ECU detects abnormal line pressure by monitoring the operation of the fluid pressure switch in each circuit.

Tech Tips

Although the DTC title indicates an incorrect gear ratio, DTC P0731-871 relates to a malfunction of the B2 hydraulic circuit.

A000WRWE12

Tech Tips


  • The preceding timing chart is for the first "Control the Shift Position" active test. The chart will differ for the second or later "Control the Shift Position" active test.

  • If "Hi" is selected in the first "Control the Shift Position" active test, it may take more time to shift to "Hi".

DTC No. INF Code DTC Detection Condition Trouble Area
P0731 871 Even if the fluid pressure was applied for low gear after the ST-on state occurred, the hybrid vehicle control ECU is not able to confirm that the fluid pressure was applied to the B2 circuit within the specified time.

  • Hybrid vehicle transmission assembly

  • Hybrid vehicle control ECU

  • Wire harness or connector

  • Transmission wire

  • Oil pressure switch

Tech Tips

ST-on is a state that occurs when the READY indicator in the combination meter blinks after the power switch is pressed with the brake pedal depressed.

WIRING DIAGRAM

A000VR4E03
*a Oil Pressure Switch
*b Hybrid Vehicle Transmission Assembly (Transmission Wire)
*c Hybrid Vehicle Control ECU

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
      P0731-871 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 AND PRESSURE SWITCH 2)


    1. A000XOVE02
      *1 Rear view of wire harness connector: (to Hybrid Vehicle Control ECU)

      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
      E58-19 (PB2) - Body ground Power switch off 10 kΩ or higher
      Result
      Result Proceed to
      Normal A
      Oil pressure switch (PB2) result is not as specified B
      Solenoid valve (SL1 or SL2) result is not as specified C

    B

    CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE) Click here

    C

    CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE) Click here

    A

  5. READ VALUE USING INTELLIGENT TESTER (B2 OIL PRESS)


    1. A000XDEE01
      *1 Front view of wire harness connector: (to Transmission Wire)

      Connect connector E58 to the hybrid vehicle control ECU.

    2. Disconnect the transmission wire connector.

    3. Turn the power switch on (IG).

      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. Select the following menu items: Powertrain / Hybrid Control / Data List / B2 Oil Pressure.

    5. Read the data list.

      OK
      Tester Display Condition Specified Condition
      B2 Oil Pressure E64-10 (PB2) is connected to body ground ON
      E64-10 (PB2) is not connected to body ground OFF

    NG

    CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE) Click here

    OK

  6. 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

  7. 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

  8. CHECK FOR INTERMITTENT PROBLEMS


    1. Check for intermittent problems Click here.


    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

  9. 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

  10. CHECK CONNECTOR CONNECTION CONDITION (PB2 OIL PRESSURE SWITCH)


    1. A000U9GE01
      *1 Transmission Wire
      *2 PB2 Oil Pressure Switch

      Remove the oil strainer assembly Click here.

    2. Check the connection of the PB2 oil pressure switch connector.

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

    NG

    CONNECT SECURELY

    OK

  11. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE)


    1. A000U9GE01
      *1 Transmission Wire
      *2 PB2 Oil Pressure Switch

      Disconnect the transmission wire connector.

    2. Disconnect the connector from the PB2 oil pressure switch.

    3. Turn the power switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side - Body ground Power switch on (IG) Below 1 V

      Note

      Turning the power switch on (IG) with the transmission wire connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    5. Turn the power switch off.

    6. A000VUFE02
      *1 Component without harness connected: (Transmission Wire)

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

      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side - PB2 (E64-10) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side or PB2 (E64-10) - Body ground and other terminals Power switch off 10 kΩ or more

    OK

    REPLACE PB2 OIL PRESSURE SWITCH Click here

    NG

    REPLACE TRANSMISSION WIRE Click here

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


    1. A000WNZE02
      *1 Front view of wire harness connector: (to Transmission Wire)
      *2 Rear view of wire harness connector: (to Hybrid Vehicle Control ECU)

      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

  13. CHECK CONNECTOR CONNECTION CONDITION (PB2 OIL PRESSURE SWITCH)


    1. A000U9GE01
      *1 Transmission Wire
      *2 PB2 Oil Pressure Switch

      Remove the oil strainer assembly Click here.

    2. Check the connection of the PB2 oil pressure switch connector.

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

    NG

    CONNECT SECURELY

    OK

  14. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE)


    1. A000U9GE01
      *1 Transmission Wire
      *2 PB2 Oil Pressure Switch

      Disconnect the transmission wire connector.

    2. Disconnect the connector from the PB2 oil pressure switch.

    3. Turn the power switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side - Body ground Power switch on (IG) Below 1 V

      Note

      Turning the power switch on (IG) with the transmission wire connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    5. Turn the power switch off.

    6. A000VUFE02
      *1 Component without harness connected: (Transmission Wire)

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

      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side - PB2 (E64-10) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      Transmission wire PB2 oil pressure switch side or PB2 (E64-10) - Body ground and other terminals Power switch off 10 kΩ or more

    OK

    REPLACE PB2 OIL PRESSURE SWITCH Click here

    NG

    REPLACE TRANSMISSION WIRE Click here

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


    1. A000XAEE01
      *1 Front view of wire harness connector: (to Transmission Wire)
      *2 Rear view of wire harness connector: (to Hybrid Vehicle Control ECU)

      Disconnect the transmission wire connector.

    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
      E58-2 (SL1-) - Body ground Power switch on (IG) Below 1 V
      E58-3 (SL1+) - Body ground Power switch on (IG) Below 1 V
      E58-10 (SL2-) - Body ground Power switch on (IG) Below 1 V
      E58-11 (SL2+) - 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
      E58-2 (SL1-) - E64-13 (SL1-) Power switch off Below 1 Ω
      E58-3 (SL1+) - E64-6 (SL1+) Power switch off Below 1 Ω
      E58-10 (SL2-) - E64-12 (SL2-) Power switch off Below 1 Ω
      E58-11 (SL2+) - E64-5 (SL2+) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      E58-2 (SL1-) or E64-13 (SL1-) - Body ground and other terminals Power switch off 10 kΩ or higher
      E58-3 (SL1+) or E64-6 (SL1+) - Body ground and other terminals Power switch off 10 kΩ or higher
      E58-10 (SL2-) or E64-12 (SL2-) - Body ground and other terminals Power switch off 10 kΩ or higher
      E58-11 (SL2+) or E64-5 (SL2+) - Body ground and other terminals Power switch off 10 kΩ or higher

    OK

    REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. A000WNZE02
      *1 Front view of wire harness connector: (to Transmission Wire)
      *2 Rear view of wire harness connector: (to Hybrid Vehicle Control ECU)

      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

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR