RX400h · Service Manual HYBRID SYSTEM

P0A79-704

Diagnostic trouble codes

DESCRIPTION

Refer to the description of the inverter. (Click here)
The MG ECU controls Motor torque according to driving conditions.
DTC No.
 INF Code
 DTC Detection Condition
 Trouble Area
P0A79
 704
 Malfunction in monitoring Rear Motor torque performance
  1. Rear traction motor w/ transaxle assembly
  2. w/ converter inverter assembly
  3. Extension wire assembly

MONITOR DESCRIPTION

If the difference between the requested MGR torque and the actual MGR torque exceeds a predetermined value, the MG HVECU determines that there is a malfunction in the execution or monitoring of the MGR torque. Then, the HV control ECU illuminates the MIL and sets a DTC.

INSPECTION PROCEDURE

CAUTION:
  1. Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are working on the high-voltage system.
  2. After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.

HINT:
At least 5 minutes is required to discharge the high-voltage capacitor inside the w/ converter inverter assembly.


1. READ OUTPUT DTC (HV)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position.

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

  1. Read output DTC. (Click here)

    Result:
    The DTCs shown in the table below are output:
    DTC No.
    		 Relevant Diagnosis
    P0A1A (all details), P0A1B (all details), P0A1C (all details)
    		 MG ECU circuit malfunction
    P0A1D (all details)
    		 HV ECU circuit malfunction
    P0A3F-243, P0A40-500, P0A41-245
    		 Motor resolver circuit malfunction
    P0A45-669, P0A46-271, P0A47-670
    		 Rear motor resolver circuit malfunction
    P0A4B-253, P0A4C-513, P0A4D-255
    		 Generator resolver circuit malfunction
    P0A93-147, P0A93-347, P0A05-776
    		 MG ECU circuit malfunction
    P0A60 (all details), P0A63 (all details)
    		 Motor current sensor circuit
    P0A69 (all details), P0A6C (all details)
    		 Rear motor current sensor circuit
    P0A72 (all details), P0A75 (all details)
    		 Generator current sensor circuit
    P0A78-510, 508, 586, 266, 272, 280, 304, 267, 278, 283, 285, 305, 523
    		 Motor inverter function malfunction
    P0A79-703, 701, 672, 690, 691, 697, 698
    		 Rear motor inverter function malfunction
    P0A7A-522, 520, 309, 321, 323, 342, 343
    		 Generator inverter function malfunction
    P0A94-585, 587, 561, 551, 588, 589, 545, 546, 552, 558, 559, 583, 584, 590
    		 Boost converter circuit
    P0AA6 (all details)
    		 High-voltage system insulation malfunction
    P3004-132
    		 High-voltage system
    P3232-749, P3233-750
    		 HV gate shutdown wiring malfunction

    HINT:
    1. Turning the ignition switch to the ON position with the service plug grip and inverter cover removed causes interlock switch system DTC P0A0D-350 to be output.
    2. P0A79-704 may be output due to a malfunction which causes the DTCs in the table above to be output. In this case, first troubleshoot the output DTCs in the table above. Then, perform a reproduction test to check that no DTCs are output.



 YES
GO TO DTC CHART
NO


2. CHECK REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY

CAUTION:
Be sure to wear insulated gloves.

  1. A105187
    Turn the ignition switch off and remove the service plug grip. (Click here)

    NOTICE:
    Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.

  1. Check that the bolts for the three-phase AC cable of the rear traction motor w/ transaxle assembly are tightened to the specified torque.

Torque:
15 N*m{ 153 kgf*cm , 11 ft.*lbf }



NG
TIGHTEN THEM TO SPECIFIED TORQUE
OK


3. CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)

CAUTION:
Be sure to wear insulated gloves.

  1. A103665E03
    Check that the service plug grip is removed.

  1. Remove the inverter cover. (Click here)

    NOTICE:
    1. Wrap the interlock round terminal for the inverter cover with vinyl tape to prevent it from shorting to ground.
    2. Prevent water in the reservoir tank from entering the inverter.
    3. Removing the inverter cover causes the MG ECU board to be exposed. Therefore, temporarily install the inverter cover for each area to be inspected.

  1. Check the connections of the MG ECU connectors.

    Result:
    Connectors are connected securely and there is no poor connection.



 NG
CONNECT SECURELY
OK


4. CHECK W/ CONVERTER INVERTER ASSEMBLY (REAR MOTOR)

CAUTION:
Be sure to wear insulated gloves.

  1. A105182E01
    Check that the service plug grip is removed.

  1. Check that the bolts for the three-phase AC cable of the rear traction motor w/ transaxle assembly are tightened to the specified torque.

Torque:
10 N*m{ 102 kgf*cm , 7 ft.*lbf }



NG
TIGHTEN THEM TO SPECIFIED TORQUE
OK


5. INSPECT REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY

CAUTION:
Be sure to wear insulated gloves.

  1. A109645E04
    Check that the service plug grip is removed.

  1. Disconnect the three-phase AC cable for Rear Motor from the inverter.

  1. A108040E04
    Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - V
    		 146 to 163 mΩ (20°C)
    V - W
    		 146 to 163 mΩ (20°C)
    W - U
    		 146 to 163 mΩ (20°C)

    NOTICE:
    If the Rear Motor temperature is too high, the resistance changes greatly. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

  1. To correct the resistance varying depending on the temperature, use the following formula to calculate the resistance at 20°C.

    HINT:
    1. R20 = Rt / {1 + 0.00393 X (T - 20)}
    2. R20: Resistance at 20 °C (mΩ)
    3. Rt: Measured resistance (mΩ)
    4. T: Temperature when the resistance is measured (°C)

  1. Calculate the difference between the maximum and minimum resistance.

    Standard resistance:
    Difference is 5 mΩ or less

  1. Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - Body ground and shielded wire ground
    		 10 MΩ or higher
    V - Body ground and shielded wire ground
    		 10 MΩ or higher
    W - Body ground and shielded wire ground
    		 10 MΩ or higher



NG
Go to step 8
OK


6. CHECK FRAME WIRE NO.3 (W/ CONVERTER INVERTER ASSEMBLY - REAR TRACTION MOTOR)

CAUTION:
Be sure to wear insulated gloves.

  1. Check that the service plug grip is removed.

  1. C105715
    Disconnect the three-phase AC cable for Rear Motor from the rear traction motor w/ transaxle assembly.

  1. A105214E01
    Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    (Rear traction motor w/ transaxle assembly side - w/ converter inverter assembly side)
    		 Specified Condition
    U - U
    		 Below 1 Ω
    V - V
    		 Below 1 Ω
    W - W
    		 Below 1 Ω



NG
REPLACE FRAME WIRE NO.3
OK


7. INSPECT EXTENSION WIRE ASSEMBLY

  1. Remove the rear traction motor w/ transaxle assembly. (Click here)

  1. Remove the extension wire assembly from the rear traction motor w/ transaxle assembly. (Click here)

  1. A112804E01
    Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - Shield shell
    		 10 MΩ or higher
    V - Shield shell
    		 10 MΩ or higher
    W - Shield shell
    		 10 MΩ or higher

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - U
    		 Below 1 Ω
    V - V
    		 Below 1 Ω
    W - W
    		 Below 1 Ω



NG
REPLACE EXTENSION WIRE ASSEMBLY
OK

REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY

8. CHECK FRAME WIRE NO.3 (W/ CONVERTER INVERTER ASSEMBLY - REAR TRACTION MOTOR)

CAUTION:
Be sure to wear insulated gloves.

  1. A105214E02
    Check that the service plug grip is removed.

  1. Disconnect the three-phase AC cable from the rear motor.

    NOTICE:
    Wrap the terminals of disconnected cable with protective tape to prevent the terminals from contacting the vehicle body.

  1. Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - Body ground
    		 10 MΩ or higher
    V - Body ground
    		 10 MΩ or higher
    W - Body ground
    		 10 MΩ or higher



NG
REPLACE FRAME WIRE NO.3
OK


9. INSPECT EXTENSION WIRE ASSEMBLY

  1. Remove the rear traction motor w/ transaxle assembly. (Click here)

  1. Remove the extension wire assembly from the rear traction motor w/ transaxle assembly. (Click here)

  1. A112804E01
    Using a megohmmeter, measure the insulation resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - Shield shell
    		 10 MΩ or higher
    V - Shield shell
    		 10 MΩ or higher
    W - Shield shell
    		 10 MΩ or higher

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    U - U
    		 Below 1 Ω
    V - V
    		 Below 1 Ω
    W - W
    		 Below 1 Ω



NG
REPLACE EXTENSION WIRE ASSEMBLY
OK

REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY


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