Lexus ES manuals

Lexus ES: Drive Motor "A" Inverter Actuator Stuck Closed (P0A7873)

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Motor Generator Control System (for Nickel Metal Hydride Battery) / Drive Motor "A" Inverter Actuator Stuck Closed (P0A7873)

DTC SUMMARY

MALFUNCTION DESCRIPTION

This DTC is stored when a short is detected in the inverter with converter assembly (motor inverter) or the hybrid vehicle transaxle assembly (motor (MG2)). The cause of this malfunction may be one of the following:

Internal inverter malfunction
  • Motor inverter internal circuit malfunction
Hybrid vehicle transaxle assembly (motor (MG2)) malfunction
  • Open or short circuit
  • Iron particles or damage from foreign objects

DESCRIPTION

For a description of the inverter.

Click here

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P0A7873

Drive Motor "A" Inverter Actuator Stuck Closed

Current flow to any phase of the motor (MG2) exceeds the threshold after the motor inverter is shut down due to a DTC indicating a motor inverter malfunction (overheating, overcurrent or circuit malfunction) being stored.

(1 trip detection logic)
  • Inverter with converter assembly
  • Motor cable
  • Hybrid vehicle transaxle assembly

Comes on

Master Warning Light:

Comes on

MONITOR DESCRIPTION

The motor generator control ECU monitors the 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 set a DTC.

MONITOR STRATEGY

Related DTCs

P0A78 (INF P0A7873): MFIV detection (Short circuit malfunction)

Required sensors/components

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 P0A78 (INF P0A7873) 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

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

    Click here

  1. Connect the Techstream to the DLC3.
  2. Turn the power switch on (IG) and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the power switch off and wait for 2 minutes or more.
  5. Turn the power switch on (IG) and turn the Techstream on.
  6. With power switch on (IG) and wait for 5 seconds or more. [*1]
  7. Turn the power switch on (READY) and wait for 5 seconds or more. [*2]
  8. Drive the vehicle for approximately 10 minutes mainly using the engine. [*3]

    NOTICE:

    As the state of charge of the HV battery may be low after driving in fail-safe mode, it will automatically be charged for 5 to 10 minutes with power switch on (READY) after repairs have been performed.

    HINT:

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

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

  9. Enter the following menus: Powertrain / Motor Generator / Utility / All Readiness.
  10. 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 or N/A, perform the normal judgment procedure again.

WIRING DIAGRAM

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

Click here

CAUTION / NOTICE / HINT

CAUTION:

  • Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
    • Inspecting the high-voltage system
    • Disconnecting the low voltage connector of the inverter with converter assembly
    • Disconnecting the low voltage connector of the HV battery
  • To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
  • After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
  • After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

    Click here

    HINT:

    Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

    *a

    Without waiting for 10 minutes

NOTICE:

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

    Click here

  • DTC P0A7873 is stored after DTCs P0A789E and/or P1C5D19 are stored. After troubleshooting and repairing the malfunction which caused DTC P0A7873 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 hybrid vehicle 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 hybrid vehicle 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 P0A9000 is not output. If DTC P0A9000 is output, replace the hybrid vehicle transaxle assembly.

PROCEDURE

1.

CHECK DTC OUTPUT (HYBRID CONTROL)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(d) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

P0A7873 only is output, or DTCs except the ones in the table below are also output.

A

Any of the following DTCs are also output.

B

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 (Hybrid/EV Battery Area) Insulation Resistance Decreased

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

HINT:

  • P0A7873 may be output as a result of the malfunctions indicated by the DTCs above.
    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.)

(e) Turn the power switch off.

B

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

A

2.

CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR (MG2))

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 power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the motor cable from the hybrid vehicle transaxle assembly.

(c) Check the motor (MG2) 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 motor (MG2) 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

Y1-1 (W) - Y1-2 (U)

Power switch off

61.4 to 68.0 mΩ

Y1-2 (U) - Y1-3 (V)

Power switch off

61.4 to 68.0 mΩ

Y1-1 (W) - Y1-3 (V)

Power switch off

61.6 to 68.2 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)

(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

Y1-1 (W) - Body ground and shield ground

Power switch off

100 MΩ or higher

Y1-2 (U) - Body ground and shield ground

Power switch off

100 MΩ or higher

Y1-3 (V) - Body ground and shield ground

Power switch off

100 MΩ or higher

(e) Connect the motor cable.

NG

GO TO STEP 5

OK

3.

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Click here

NEXT

4.

REPLACE MOTOR CABLE

Click here

NEXT

GO TO STEP 8

5.

REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

Click here

NEXT

6.

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Click here

NEXT

7.

REPLACE MOTOR CABLE

Click here

NEXT

8.

CHECK DTC OUTPUT (MOTOR GENERATOR CONTROL SYSTEM)

(a) Check the other DTCs that were output together with DTC P0A7873.

Powertrain > Motor Generator > Trouble Codes

Relevant DTC

P0A789E

Drive Motor "A" Inverter Stuck On

P1C5D19

Drive Motor "A" Inverter Circuit Current Above Threshold

NOTICE:

DTC P0A7873 is stored after DTCs P0A789E and/or P1C5D19 are stored. After troubleshooting and repairing the malfunction which caused P0A7873 to be stored, be sure to troubleshoot the other DTCs.

NEXT

GO TO DTC CHART (MOTOR GENERATOR CONTROL SYSTEM)

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