RX400h · Service Manual HYBRID SYSTEM

P0A78-504

Diagnostic trouble codes

DESCRIPTION

Refer to the description of the inverter. (Click here)
DTC No.
 INF Code
 DTC Detection Condition
 Trouble Area
P0A78
 504
 Motor inverter overvoltage signal detection (overvoltage by HV transaxle assembly malfunction)
  1. Wire harness or connector
  2. HV relay assembly
  3. w/ converter inverter assembly (MG ECU)
  4. Rear traction motor w/ transaxle assembly
  5. Hybrid vehicle transaxle assembly

MONITOR DESCRIPTION

If the motor inverter detects over-voltage, it transmits an over-voltage signal to the MG ECU. Upon receiving this signal, 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 DTCs. (Click here)

    Result:
    The DTCs shown in the table below are output:
    DTC No.
    		 INF Code
    		 Detection Item
    P0A3F
    		 243
    		 Motor resolver circuit
    P0A40
    		 500
    		 Motor resolver output is out of normal range
    P0A41
    		 245
    		 Motor resolver malfunction (Low)
    P0A45
    		 669
    		 Interphase short in Rear Motor resolver circuit
    P0A46
    		 671
    		 Rear motor resolver output is out of normal range
    P0A47
    		 670
    		 Rear motor resolver malfunction (Low)
    P0A4B
    		 253
    		 Generator resolver circuit
    P0A4C
    		 513
    		 Generator resolver output is out of normal range
    P0A4D
    		 255
    		 Generator resolver malfunction (Low)
    P0A78
    		 266, 280
    		 Motor inverter function malfunction
    P0A94
    		 558, 559, 588, 589
    		 Boost converter circuit malfunction
    P0A95
    		 123
    		 High voltage fuse blown out
    P0AA1
    		 226
    		 SMR+ stuck closed
    P0AA2
    		 227
    		 SMR+ stuck open
    P0AA4
    		 228
    		 SMR- stuck closed
    P0AA5
    		 229
    		 SMR- stuck open
    P3004
    		 803
    		 High-current 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. P0A78-504 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. A103665E01
    Check the connections of the MG ECU connectors.

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



 NG
CONNECT SECURELY
OK


3. INSPECT HV RELAY ASSEMBLY (SMR2)

CAUTION:
Be sure to wear insulated gloves and protective goggles.

  1. Check that the service plug grip is removed.

  1. Remove the HV relay assembly from the vehicle. (Click here)

  1. A108055E07
    Measure the resistance according to the value(s) in the table below.

Standard Resistance :
Tester Condition
 Specified Condition
S47-1 - S44-1
 Below 1 Ω
(Apply auxiliary battery voltage between terminals (CON2 (S48-1) and GND (S48-4))

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

    Standard Resistance :
    Tester Condition
    		 Specified Condition
    CON2 (S48-1) - GND (S48-4)
    		 20 to 60 Ω
    at -35 to 80°C ( -31 to 176°F)



NG
REPLACE HV RELAY ASSEMBLY
OK


4. INSPECT HV RELAY ASSEMBLY (SMR3)

CAUTION:
Be sure to wear insulated gloves.

  1. Check that the service plug grip is removed.

  1. A108054E04
    Measure the resistance according to the value(s) in the table below.

Standard Resistance :
Tester Condition
 Specified Condition
S49-1 - S45-1
 Below 1 Ω
(Apply auxiliary battery voltage between terminals (CON3 (S48-2) and GND (S48-4))

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

Standard Resistance :
Tester Condition
 Specified Condition
CON3 (S48-2) - GND (S48-4)
 20 to 60 Ω
at -35 to 80°C ( -31 to 176°F)



NG
REPLACE HV RELAY ASSEMBLY
OK


5. CONFIRM INFORMATION (EXCLUSIVE INFO 4)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position and check for HV system DTC P0A0D-350 by following the prompts on the intelligent tester screen.

    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. Display freeze frame data corresponding to DTC P0A94 and select the information.

  1. Select INF code 556 and read "Exclusive Info 4".

    Result::
    Displayed item in exclusive information 4
    		 Proceed to
    -63 to 64
    		 A
    65 to 128
    		 B



B
Go to step 8
A


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

  1. A103666E04
    Disconnect the I24 connector from the MG ECU.

  1. 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
    MRF (I24-13) - Body ground
    		 Below 1 V
    MRFG (I24-23) - Body ground
    		 Below 1 V
    MSN (I24-21) - Body ground
    		 Below 1 V
    MSNG (I24-20) - Body ground
    		 Below 1V
    MCS (I24-19) - Body ground
    		 Below 1 V
    MCSG (I24-18) - Body ground
    		 Below 1 V

  1. Turn the ignition switch off.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    MRF (I24-13) - MRFG (I24-23)
    		 7.65 to 10.2 Ω
    MSN (I24-21) - MSNG (I24-20)
    		 12.6 to 16.8 Ω
    MCS (I24-19) - MCSG (I24-18)
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    MRF (I24-13) or MRFG (I24-23) - Body ground
    		 10 kΩ or higher
    MSN (I24-21) or MSNG (I24-20) - Body ground
    		 10 kΩ or higher
    MCS (I24-19) or MCSG (I24-18) - Body ground
    		 10 kΩ or higher



NG
Go to step 9
OK


7. CHECK HARNESS AND CONNECTOR (MG ECU -GENERATOR RESOLVER)

  1. A103666E03
    Disconnect the I24 connector from the MG ECU.

  1. 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
    GRF (I24-12) - Body ground
    		 Below 1 V
    GRFG (I24-23) - Body ground
    		 Below 1 V
    GSN (I24-11) - Body ground
    		 Below 1 V
    GSNG (I24-10) - Body ground
    		 Below 1V
    GCS (I24-9) - Body ground
    		 Below 1 V
    GCSG (I24-8) - Body ground
    		 Below 1 V

  1. Turn the ignition switch off.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    GRF (I24-12) - GRFG (I24-22)
    		 7.65 to 10.2 Ω
    GSN (I24-11) - GSNG (I24-10)
    		 12.6 to 16.8 Ω
    GCS (I24-9) - GCSG (I24-8)
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    GRF (I24-12) or GRFG (I24-22) - Body ground
    		 10 kΩ or higher
    GSN (I24-11) or GSNG (I24-10) - Body ground
    		 10 kΩ or higher
    GCS (I24-9) or GCSG (I24-8) - Body ground
    		 10 kΩ or higher



NG
Go to step 10
OK

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

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

  1. A103667E04
    Disconnect the I25 connector from the MG ECU.

  1. 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 1V
    RCS (I25-11) - Body ground
    		 Below 1 V
    RCSG (I25-23) - Body ground
    		 Below 1 V

  1. Turn the ignition switch off.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    RRF (I25-21) - Body ground
    		 7.65 to 10.2 Ω
    RSN (I25-29) - Body ground
    		 12.6 to 16.8 Ω
    RCS (I25-11) - Body ground
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    RRF (I25-21) or RRFG (I25-22) - Body ground
    		 10 kΩ or higher
    RSN (I25-29) or RSNG (I25-30) - Body ground
    		 10 kΩ or higher
    RCS (I25-11) or RCSG (I25-23) - Body ground
    		 10 kΩ or higher



NG
Go to step 11
OK

REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY

9. INSPECT MOTOR RESOLVER

  1. A083675E04
    Disconnect the M7 motor resolver connector.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    MRF (M7-1) - MRFG (M7-4)
    		 7.65 to 10.2 Ω
    MSN (M7-2) - MSNG (M7-5)
    		 12.6 to 16.8 Ω
    MCS (M7-3) - MCSG (M7-6)
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    MRF (M7-1) - MSN (M7-2)
    		 10 MΩ or higher
    MRF (M7-1) - MCS (M7-3)
    		 10 MΩ or higher
    MSN (M7-2) - MCS (M7-3)
    		 10 MΩ or higher
    MRFG (M7-4) - MSNG (M7-5)
    		 10 MΩ or higher
    MRFG (M7-4) - MCSG (M7-6)
    		 10 MΩ or higher
    MSNG (M7-5) - MCSG (M7-6)
    		 10 MΩ or higher
    Each terminal listed above - transaxle housing
    		 10 MΩ or higher



NG
REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR

10. INSPECT GENERATOR RESOLVER

  1. Remove the w/ converter inverter assembly. (Click here)

  1. A105163E02
    Disconnect the M6 generator resolver connector.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    GRF (M6-1) - GRFG (M6-6)
    		 7.65 to 10.2 Ω
    GSN (M6-2) - GSNG (M6-7)
    		 12.6 to 16.8 Ω
    GCS (M6-3) - GCSG (M6-8)
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    GRF (M6-1) - GSN (M6-2)
    		 10 MΩ or higher
    GRF (M6-1) - GCS (M6-3)
    		 10 MΩ or higher
    GSN (M6-2) - GCS (M6-3)
    		 10 MΩ or higher
    GRFG (M6-6) - GSNG (M6-7)
    		 10 MΩ or higher
    GRFG (M6-6) - GCSG (M6-8)
    		 10 MΩ or higher
    GSNG (M6-7) - GCSG (M6-8)
    		 10 MΩ or higher
    Each terminal listed above - transaxle housing
    		 10 MΩ or higher



NG
REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR

11. INSPECT REAR MOTOR RESOLVER

  1. A083675E05
    Disconnect the M11 rear motor resolver connector.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    RRF (M11-1) - RRFG (M11-4)
    		 7.65 to 10.2 Ω
    RSN (M11-2) - RSNG (M11-5)
    		 12.6 to 16.8 Ω
    RCS (M11-3) - RCSG (M11-6)
    		 12.6 to 16.8 Ω

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    MRF (M11-1) - MSN (M11-2)
    		 10 MΩ or higher
    RRF (M11-1) - RCS (M11-3)
    		 10 MΩ or higher
    RSN (M11-2) - RCS (M11-3)
    		 10 MΩ or higher
    RRFG (M11-4) - RSNG (M11-5)
    		 10 MΩ or higher
    RRFG (M11-4) - RCSG (M11-6)
    		 10 MΩ or higher
    RSNG (M11-5) - RCSG (M11-6)
    		 10 MΩ or higher
    Each terminal listed above - transaxle housing
    		 10 MΩ or higher



NG
REPLACE REAR TRACTION MOTOR W/TRANSAXLE ASSEMBLY
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR


← P0A78-306P0A78-506 →