RX400h · Service Manual HYBRID SYSTEM

P0A79-812

Diagnostic trouble codes

DESCRIPTION

Refer to the description of the inverter. (Click here)
If abnormal current flows through the Rear Motor, the MG ECU detects the abnormal current and sends a signal to inform the HV control ECU of the malfunction.
DTC No.
 INF Code
 DTC Detection Condition
 Trouble Area
P0A79
 812
 Abnormal Rear Motor current value detection (MG ECU malfunction)
  1. Wire harness or connector
  2. Rear traction motor w/ transaxle assembly
  3. w/ converter inverter assembly (MG ECU)
P0A79
 813
 Abnormal Rear Motor current value detection (inverter malfunction)
  1. Wire harness or connector
  2. Rear traction motor w/ transaxle assembly
  3. w/ converter inverter assembly (MG ECU)
P0A79
 814
 Abnormal Rear Motor current value detection (rear traction motor w/ transaxle assembly malfunction)
  1. Wire harness or connector
  2. Rear traction motor w/ transaxle assembly
  3. w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

When the MG ECU detects an abnormal current in the rear motor inverter, 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.

    HINT:
    Turning the ignition switch to the ON position with the service plug grip and inverter cover removed causes interlock switch system DTCs to be output.

  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
    P0A1D
    		 HV ECU circuit malfunction
    P0A45, P0A46, P0A47
    		 Rear motor resolver circuit
    P0A69, P0A6C
    		 Rear motor current sensor circuit
    P0A79 (Except for 812, 813, and 814)
    		 Rear motor inverter function malfunction
    P0A91
    		 Rear motor function malfunction
    P0A1C
    		 MG ECU circuit

    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. P0A79-812 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 CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)

CAUTION:
Be sure to wear insulated gloves.

  1. 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. 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. A103665E03
    Check the connections of the MG ECU connectors.

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



 NG
CONNECT SECURELY
OK


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

CAUTION:
Be sure to wear insulated gloves.

  1. A105182E02
    Check that the service plug grip is removed.

  1. Check that the bolts for the three-phase AC cable for Rear Motor are tightened to the specified torque.

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



NG
TIGHTEN THEM TO SPECIFIED TORQUE
OK


4. CHECK HARNESS AND CONNECTOR (MG ECU - REAR MOTOR RESOLVER)

CAUTION:
Be sure to wear insulated gloves.

  1. Check that the service plug grip is removed.

  1. Disconnect the I25 connector from the MG ECU.

  1. Disconnect the M11 rear motor resolver connector.

  1. A105213E02
    Measure the voltage according to the value(s) in the table below when the ignition switch is in the ON position.)

    Standard Voltage:
    Tester Connection
    		 Specified Condition
    RRF (I25-21) - Body ground
    		 Below 1 V
    RRFG (I25-22) - Body ground
    		 Below 1 V
    RSN (I25-29) - Body ground
    		 Below 1 V
    RSNG (I25-30) - Body ground
    		 Below 1 V
    RCS (I25-11) - Body ground
    		 Below 1 V
    RCSG (I25-23) - Body ground
    		 Below 1 V

    NOTICE:
    Turning the ignition switch to the ON position with the MG ECU connectors disconnected causes other DTCs to be stored. Clear the DTCs after performing the inspection.

  1. Turn the ignition switch off.

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

    Standard Resistance (Check for open):
    Tester Connection
    		 Specified Condition
    RRF (I25-21) - RRF (M11-1)
    		 Below 1 Ω
    RRFG (I25-22) - RRFG (M11-4)
    		 Below 1 Ω
    RSN (I25-29) - RSN (M11-2)
    		 Below 1 Ω
    RSNG (I25-30) - RSNG (M11-5)
    		 Below 1 Ω
    RCS (I25-11) - RCS (M11-3)
    		 Below 1 Ω
    RCSG (I25-23) - RCSG (M11-6)
    		 Below 1 Ω

    Standard Resistance (Check for short):
    Tester Connection
    		 Specified Condition
    RRF (I25-21) or RRF (M11-1) - Body ground
    		 10 kΩ or higher
    RRFG (I25-22) or RRFG (M11-4) - Body ground
    		 10 kΩ or higher
    RSN (I25-29) or RSN (M11-2) - Body ground
    		 10 kΩ or higher
    RSNG (I25-30) or RSNG (M11-5) - Body ground
    		 10 kΩ or higher
    RCS (I25-11) or RCS (M11-3) - Body ground
    		 10 kΩ or higher
    RCSG (I25-23) or RCSG (M11-6) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY


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