Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000026QHN
Model Year Start: 2023 Model: Corolla HV Prod Date Range: [09/2022 -           ]
Title: HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P0A7973; Drive Motor "B" Inverter Actuator Stuck Closed; 2023 - 2025 MY Corolla HV [09/2022 -        ]

DTC

P0A7973

Drive Motor "B" Inverter Actuator Stuck Closed

DTC SUMMARY

MALFUNCTION DESCRIPTION

This DTC is stored when a short is detected in the inverter with converter assembly (rear motor inverter) or the rear traction motor with transaxle assembly (rear motor (MGR)). The cause of this malfunction may be one of the following:

Internal inverter malfunction

  • Rear motor inverter internal circuit malfunction

Rear traction motor with transaxle assembly (rear motor (MGR)) malfunction

  • Open or short circuit
  • Iron particles or damage from foreign objects

DESCRIPTION

For a description of the inverter.

Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P0D2D16,...,P0D2D1F; Drive Motor "A" Inverter Voltage Sensor(VH) Circuit Voltage Below Threshold+

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Note

P0A7973

Drive Motor "B" Inverter Actuator Stuck Closed

Current flow to any phase of the rear motor (MGR) exceeds the threshold after the rear motor inverter is shut down due to a DTC indicating a rear motor inverter malfunction (overheating, overcurrent or circuit malfunction) being stored.

(1 trip detection logic)
  • Inverter with converter assembly
  • HV floor under wire (rear traction motor cable)
  • Rear traction motor with transaxle assembly

Comes on

Master Warning:

Comes on

SAE Code:

P0A79

MONITOR DESCRIPTION

The motor generator control ECU monitors the rear motor inverter electric current. If the current exceeds the threshold for a specified period of time, the motor generator control ECU will illuminate the MIL and store a DTC.

MONITOR STRATEGY

Related DTCs

P0A79 (INF P0A7973): RFIV detection (Short circuit malfunction)

Required sensors/components

Rear motor inverter

Frequency of operation

Continuous

Duration

TMC's intellectual property

MIL operation

1 driving cycle

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored

TMC's intellectual property

Other conditions belong to TMC's intellectual property

-

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property

-

COMPONENT OPERATING RANGE

Motor generator control ECU

DTC P0A79 (INF P0A7973) is not detected

CONFIRMATION DRIVING PATTERN

HINT:

  • After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

    Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): UTILITY

  • When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

    Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): DTC CHECK / CLEAR

  1. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  2. Turn the ignition switch off and wait for 2 minutes or more.
  3. Turn the ignition switch to ON and wait for 5 seconds or more. [*1]
  4. Turn the ignition switch to ON (READY) and wait for 5 seconds or more. [*2]
  5. With the vehicle stopped, begin moving with the accelerator opening angle between 20% to 50% and a speed of approximately 10 km/h (6 mph), then stop the vehicle and repeat the same procedure several times. [*3]

    HINT:

    • While doing this, check that the "Rear Motor Torque" value does not remain at 0 N*m continuously, but rather changes to indicate that the rear motor is operating.

      (Unless rear motor torque is restricted due to DTC output, the rear motor torque will not remain at 0 N*m continuously.)

    • [*1] to [*3]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

  6. Enter the following menus: Powertrain / Motor Generator / Utility / All Readiness.
  7. Check the DTC judgment result.

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE, perform the normal judgment procedure again.

WIRING DIAGRAM

Refer to the wiring diagram for the Rear Motor High-voltage Circuit.

Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): Rear Motor High-voltage Circuit+

CAUTION / NOTICE / HINT

CAUTION:

Refer to the precautions before inspecting high voltage circuit.

Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: MOTOR GENERATOR CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): PRECAUTION

NOTICE:

  • After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; SETUP: WHEN DISCONNECTING OR RECONNECTING BATTERY TERMINAL: BEFORE DISCONNECTING BATTERY

  • When disconnecting and reconnecting the auxiliary battery

    HINT:

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; SETUP: WHEN DISCONNECTING OR RECONNECTING BATTERY TERMINAL: AUTOMATIC LEARNING CHART 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; SETUP: WHEN DISCONNECTING OR RECONNECTING BATTERY TERMINAL: AUTOMATIC LEARNING CHART

  • DTC P0A7973 is stored after DTCs P0A799E and/or P1C5E19 are stored. After troubleshooting and repairing the malfunction which caused DTC P0A7973 to be stored, be sure to troubleshoot the other DTCs.
  • Depending on the conditions in which the vehicle is being operated when a short circuit occurs in the inverter with converter assembly, the rear traction motor with transaxle assembly may be affected. As this DTC is stored if a short circuit occurs in the inverter with converter assembly, it is necessary to perform a road test to check the rear traction motor with transaxle assembly. If problems are found, replace the malfunctioning parts.
  • After completing the repair, including the repair of previously output DTCs, drive the vehicle at a speed of approximately 40 km/h (25 mph) for 1 minute and check that DTC P0A9100 is not output. If DTC P0A9100 is output, replace the rear traction motor with transaxle assembly.

HINT:

P0A7973 may be output as a result of the malfunctions indicated by the DTCs in table below.

  1. The chart above is listed in inspection order of priority.
  2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)

Malfunction Content

Relevant DTC

Insulation malfunction

P1C7C49

Hybrid/EV Battery Voltage System Isolation (A/C Area) Internal Electronic Failure

P1C7D49

Hybrid/EV Battery Voltage System Isolation (Hybrid/EV Battery Area) Internal Electronic Failure

P1C7E49

Hybrid/EV Battery Voltage System Isolation (Transaxle Area) Internal Electronic Failure

P1C7F49

Hybrid/EV Battery Voltage System Isolation (Direct Current Area) Internal Electronic Failure

P1C8049

Hybrid/EV Battery Voltage System Isolation (Rear Motor Area) Internal Electronic Failure

PROCEDURE

1.

CHECK REAR TRACTION MOTOR WITH TRANSAXLE ASSEMBLY (REAR MOTOR (MGR))

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the HV floor under wire (rear traction motor cable) from the rear traction motor with transaxle assembly.

(c) Check the rear motor (MGR) for an interphase short using a milliohmmeter.

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

HINT:

If the rear motor (MGR) temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle has been stopped.

Standard Resistance:

Tester Connection

Condition

Specified Condition

c3-1 (U) - c3-2 (V)

Ignition switch off

90.3 to 100.9 mΩ

c3-2 (V) - c3-3 (W)

Ignition switch off

90.3 to 100.9 mΩ

c3-3 (W) - c3-1 (U)

Ignition switch off

90.5 to 101.1 mΩ

HINT:

To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68°F).

  • R20 = Rt / {1 + 0.00393 X (T - 20)}

The calculation is based on the following:

  • R20: Resistance at 20°C (68°F) (mΩ)
  • Rt: Measured resistance (mΩ)
  • T: Temperature when the resistance is measured (°C)

*a

HV floor under wire (rear traction motor cable) not connected

(Rear Traction Motor with Transaxle Assembly)

(d) Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

NOTICE:

Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

Standard Resistance:

Tester Connection

Condition

Specified Condition

c3-1 (U) - Body ground and shield ground

Ignition switch off

100 MΩ or higher

c3-2 (V) - Body ground and shield ground

Ignition switch off

100 MΩ or higher

c3-3 (W) - Body ground and shield ground

Ignition switch off

100 MΩ or higher

(e) Connect the HV floor under wire (rear traction motor cable).

NG

GO TO STEP 4

OK

2.

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: INVERTER WITH CONVERTER: REMOVAL

NEXT

3.

REPLACE HV FLOOR UNDER WIRE (REAR TRACTION MOTOR CABLE)

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: FRAME WIRE: REMOVAL

NEXT

GO TO STEP 7

4.

REPLACE REAR TRACTION MOTOR WITH TRANSAXLE ASSEMBLY

Click here 2023 MY Corolla Corolla HV [09/2022 - 11/2022]; Q810 (HYBRID TRANSMISSION / TRANSAXLE): REAR TRACTION MOTOR: REMOVAL 2023 - 2025 MY Corolla Corolla HV [11/2022 -        ]; Q810 (HYBRID TRANSMISSION / TRANSAXLE): REAR TRACTION MOTOR: REMOVAL

NEXT

5.

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: INVERTER WITH CONVERTER: REMOVAL

NEXT

6.

REPLACE HV FLOOR UNDER WIRE (REAR TRACTION MOTOR CABLE)

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: FRAME WIRE: REMOVAL

NEXT

7.

CHECK DTC OUTPUT (MOTOR GENERATOR)

(a) Check the other DTCs that were output together with DTC P0A7973.

Powertrain > Motor Generator > Trouble Codes

Relevant DTC

P0A799E

Drive Motor "B" Inverter Stuck On

P1C5E19

Drive Motor "B" Inverter Circuit Current Above Threshold

NOTICE:

DTC P0A7973 is stored after DTCs P0A799E and/or P1C5E19 are stored. After troubleshooting and repairing the malfunction which caused P0A7973 to be stored, be sure to troubleshoot the other DTCs.

NEXT

GO TO DTC CHART (MOTOR GENERATOR CONTROL SYSTEM)