Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Hybrid/EV Battery Negative Contactor Actuator Stuck Closed (P0AA373)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Engine / Hybrid / Battery Control / Hybrid Control System / Hybrid/EV Battery Negative Contactor Actuator Stuck Closed (P0AA373)

DTC SUMMARY

MALFUNCTION DESCRIPTION

The hybrid vehicle control ECU detects a stuck closed malfunction of a system main relay on the HV battery negative side.

The cause of this malfunction may be one of the following:

Inverter voltage sensor (VH) internal circuit malfunction
  • Voltage sensor (VH) malfunction
  • Motor generator control ECU (MG ECU) malfunction
  • Communication (wire harness) malfunction
High voltage system malfunction
  • HV battery junction block assembly malfunction
Low-voltage circuit (12 V) malfunction
  • Hybrid vehicle control ECU malfunction
  • HV battery junction block assembly malfunction
  • Low voltage wire harness malfunction
  • Low voltage connector malfunction

DESCRIPTION

Refer to the description for DTC P0AE411.

Click here

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P0AA373

Hybrid/EV Battery Negative Contactor Actuator Stuck Closed

Even the system main relay of HV battery negative (-) terminal side is turned off, the inverter voltage (VH) does not drop.

(1 trip detection logic)

  • HV battery junction block assembly
  • Inverter with converter assembly
  • Hybrid vehicle control ECU
  • Wire harness or connector

Does not come on

Master Warning Light:

Comes on

Related Data List

DTC No.

Data List

P0AA373

  • Hybrid Battery Voltage
  • VH-Voltage after Boosting
  • VL-Voltage before Boosting

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

  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. Turn the power switch on (READY) and wait for 3 minutes or more.

    HINT:

    According to the display on the Techstream, read the Data List and monitor the values of "Hybrid Battery Voltage" and "VL-Voltage before Boosting" for 3 minutes. If the difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is always less than 100 V, the vehicle has returned to normal.

  7. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
  8. 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 driving pattern again.

WIRING DIAGRAM

Refer to the wiring diagram for the HV battery high-voltage line 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

  • Make sure to insulate the high-voltage connectors and terminals of the HV battery with insulating tape after removing it.

    If the HV battery stored without insulating the connectors and terminals, electric shock or fire may result.

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

  • If the DTCs are cleared or the cable is disconnected and reconnected to the negative (-) auxiliary battery terminal before performing repairs, turning the power switch on (READY) may cause a malfunction. Do not turn the power switch on (READY).

HINT:

If DTC P0AA373 is output, the power switch cannot be turned on (READY).

PROCEDURE

1.

CHECK DTC OUTPUT (HYBRID CONTROL, MOTOR GENERATOR)

(a) Connect the Techstream to the DLC3.

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

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

(d) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes Powertrain > Motor Generator > Trouble Codes

Result

Proceed to

P0AA373 only is output, or DTCs except the ones in the table below are also output.

A

DTCs of hybrid control system in the tables below are output.

B

DTCs of motor generator control system in the tables below are output.

C

Malfunction Content

System

Relevant DTC

Microcomputer malfunction

Hybrid control system

P060647

Hybrid/EV Powertrain Control Module Processor Watchdog / Safety MCU Failure

P060687

Hybrid/EV Powertrain Control Module Processor to Monitoring Processor Missing Message

P060A47

Hybrid/EV Powertrain Control Module Monitoring Processor Watchdog / Safety MCU Failure

P060A87

Hybrid/EV Powertrain Control Module Processor from Monitoring Processor Missing Message

P0A1B49

Drive Motor "A" Control Module Internal Electronic Failure

P1C9E9F

Hybrid/EV System Reset Stuck Off

P0AFC96

Hybrid/EV Battery Sensor Module Component Internal Failure

P0AFC00

Hybrid/EV Battery Sensor Module

Motor generator control system

P0A1B1F

Generator Control Module Circuit Intermittent

P0A1A47

Generator Control Module Watchdog / Safety μC Failure

P0A1A49

Generator Control Module Internal Electronic Failure

P1C2A1C

Generator A/D Converter Circuit Circuit Voltage Out of Range

P1C2A49

Generator A/D Converter Circuit Internal Electronic Failure

P1C2B1C

Drive Motor "A" Control Module A/D Converter Circuit Voltage Out of Range

P1C2B49

Drive Motor "A" Control Module A/D Converter Circuit Internal Electronic Failure

P1CAC49

Generator Position Sensor Internal Electronic Failure

P1CAD49

Drive Motor "A" Position Sensor Internal Electronic Failure

P1CAF38

Generator Position Sensor REF Signal Cycle Malfunction Signal Frequency Incorrect

P1CB038

Drive Motor "A" Position Sensor REF Signal Frequency Incorrect

P313383

Communication Error from Generator to Drive Motor "A" Value of Signal Protection Calculation Incorrect

P313386

Communication Error from Generator to Drive Motor "A" Signal Invalid

P313387

Communication Error from Generator to Drive Motor "A" Missing Message

Power source circuit malfunction

Hybrid control system

P0AFC16

Hybrid/EV Battery Sensor Module Circuit Voltage Below Threshold

Motor generator control system

P06D61C

Generator Control Module Offset Power Circuit Voltage Out of Range

P06B01C

Generator Control Module Position Sensor REF Power Source Circuit Voltage Out of Range

Communication system malfunction

Hybrid control system

P312387

Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message

U029A87

Lost Communication with Hybrid/EV Battery Sensor Module Missing Message

Sensor and actuator circuit malfunction

Hybrid control system

P0AD911

Hybrid/EV Battery Positive Contactor Circuit Short to Ground

P0AD915

Hybrid/EV Battery Positive Contactor Circuit Short to Auxiliary Battery or Open

P0ADD11

Hybrid/EV Battery Negative Contactor Circuit Short to Ground

P0ADD15

Hybrid/EV Battery Negative Contactor Circuit Short to Auxiliary Battery or Open

P0AE411

Hybrid/EV Battery Precharge Contactor Circuit Short to Ground

P0AE415

Hybrid/EV Battery Precharge Contactor Circuit Short to Auxiliary Battery or Open

P0B3B14

Hybrid/EV Battery Voltage Sensor "A" Circuit Short to Ground or Open

P0B4014

Hybrid/EV Battery Voltage Sensor "B" Circuit Short to Ground or Open

P0B4514

Hybrid/EV Battery Voltage Sensor "C" Circuit Short to Ground or Open

P0B4A14

Hybrid/EV Battery Voltage Sensor "D" Circuit Short to Ground or Open

P0B4F14

Hybrid/EV Battery Voltage Sensor "E" Circuit Short to Ground or Open

P0B5414

Hybrid/EV Battery Voltage Sensor "F" Circuit Short to Ground or Open

P0B5914

Hybrid/EV Battery Voltage Sensor "G" Circuit Short to Ground or Open

P0B5E14

Hybrid/EV Battery Voltage Sensor "H" Circuit Short to Ground or Open

P0B6314

Hybrid/EV Battery Voltage Sensor "I" Circuit Short to Ground or Open

P0B6814

Hybrid/EV Battery Voltage Sensor "J" Circuit Short to Ground or Open

P0B6D14

Hybrid/EV Battery Voltage Sensor "K" Circuit Short to Ground or Open

P0B7214

Hybrid/EV Battery Voltage Sensor "L" Circuit Short to Ground or Open

P308A13

Hybrid/EV Battery Voltage Sensor All Circuit Open

P0AFC62

Hybrid/EV Battery Sensor Module Signal Compare Failure

P308A12

Hybrid/EV Battery Voltage Sensor All Circuit Short to Auxiliary Battery

Motor generator control system

P0A3F16

Drive Motor "A" Position Sensor Circuit Voltage Below Threshold

P0A4B16

Generator Position Sensor Circuit Voltage Below Threshold

P0A4B21

Generator Position Sensor Signal Amplitude < Minimum

P0A4B22

Generator Position Sensor Signal Amplitude > Maximum

P0C5013

Drive Motor "A" Position Sensor Circuit "A" Circuit Open

P0C5016

Drive Motor "A" Position Sensor Circuit "A" Circuit Voltage Below Threshold

P0C5017

Drive Motor "A" Position Sensor Circuit "A" Circuit Voltage Above Threshold

P0C5A13

Drive Motor "A" Position Sensor Circuit "B" Circuit Open

P0C5A16

Drive Motor "A" Position Sensor Circuit "B" Circuit Voltage Below Threshold

P0C5A17

Drive Motor "A" Position Sensor Circuit "B" Circuit Voltage Above Threshold

P0C6413

Generator Position Sensor Circuit "A" Circuit Open

P0C6416

Generator Position Sensor Circuit "A" Circuit Voltage Below Threshold

P0C6417

Generator Position Sensor Circuit "A" Circuit Voltage Above Threshold

P0C6913

Generator Position Sensor Circuit "B" Circuit Open

P0C6916

Generator Position Sensor Circuit "B" Circuit Voltage Below Threshold

P0C6917

Generator Position Sensor Circuit "B" Circuit Voltage Above Threshold

System malfunction

Hybrid control system

P0C7600

Hybrid/EV Battery System Discharge Time Too Long

P0D2D1C

Drive Motor "A" Inverter Voltage Sensor Voltage Out of Range

P1C8349

High Voltage Power Resource Circuit Voltage Sensor after Boosting Malfunction

Motor generator control system

P0D2D16

Drive Motor "A" Inverter Voltage Sensor (VH) Circuit Voltage Below Threshold

P0D2D17

Drive Motor "A" Inverter Voltage Sensor (VH) Circuit Voltage Above Threshold

P1CB69E

Drive Motor "A" Inverter Voltage Sensor (VH) Stuck On

HINT:

  • P0AA373 may be output as a result of the malfunction 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)

C

GO TO DTC CHART (MOTOR GENERATOR CONTROL SYSTEM)

A

2.

CHECK FREEZE FRAME DATA (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) Read the freeze frame data of DTC P0AA373.

Powertrain > Hybrid Control > Trouble Codes

NOTICE:

As freeze frame data is stored immediately before and after a DTC is stored, make sure to only read the values for the moment the DTC was stored ("0(s)").

Result

Proceed to

Difference between "VL-Voltage before Boosting" and "VH-Voltage after Boosting" is less than 76 V.

A

Difference between "VL-Voltage before Boosting" and "VH-Voltage after Boosting" is 76 V or more.

B

HINT:

If VH-Voltage after Boosting is output even when an off command is being sent to the system main relay (positive side), P0AA373 is output. If the difference between the "VL-Voltage before Boosting" and the "VH-Voltage after Boosting" is large, it is determined that there is an inverter (VH sensor) malfunction.

(e) Turn the power switch off.

B

REPLACE INVERTER WITH CONVERTER ASSEMBLY

A

3.

CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

Click here

OK

GO TO STEP 5

NG

4.

CONNECT SECURELY

NEXT

5.

CHECK CONNECTOR CONNECTION CONDITION (FLOOR WIRE CONNECTOR)

Click here

Result

Proceed to

OK

A

NG (The connector is not connected securely.)

B

NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.)

C

A

GO TO STEP 8

C

GO TO STEP 7

B

6.

CONNECT SECURELY

NEXT

GO TO STEP 8

7.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

8.

CHECK CONNECTOR CONNECTION CONDITION (HV BATTERY JUNCTION BLOCK ASSEMBLY CONNECTOR)

Click here

OK

GO TO STEP 10

NG

9.

CONNECT SECURELY

NEXT

10.

CHECK GROUND WIRE CONNECTION CONDITION (SMR ACTIVATION LOW-VOLTAGE CIRCUIT)

Click here

OK

GO TO STEP 12

NG

11.

CONNECT SECURELY

NEXT

12.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - HV BATTERY JUNCTION BLOCK ASSEMBLY)

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) Remove the No. 1 HV battery cover panel RH.

Click here

(c) Disconnect the K18 HV battery junction block assembly connector.

(d) Disconnect the G46 hybrid vehicle control ECU connector.

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

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

G46-1 (SMRG) - K18-4 (SMRG)

Power switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

G46-1 (SMRG) or K18-4 (SMRG) - Body ground and other terminals

Power switch off

10 kΩ or higher

*a

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

*b

Front view of wire harness connector

(to HV Battery Junction Block Assembly)

(f) Reconnect the G46 hybrid vehicle control ECU connector.

(g) Reconnect the K18 HV battery junction block assembly connector.

(h) Install the No. 1 HV battery cover panel RH.

OK

GO TO STEP 14

NG

13.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

14.

CHECK HARNESS AND CONNECTOR (HV BATTERY JUNCTION BLOCK ASSEMBLY - BODY GROUND)

Click here

OK

GO TO STEP 16

NG

15.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

16.

INSPECT HV BATTERY JUNCTION BLOCK ASSEMBLY (SMRG)

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) Remove the No. 1 HV battery cover panel RH.

Click here

(c) Disconnect the K18 HV battery junction block assembly connector.

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

*a

Component without harness connected

(HV Battery Junction Block Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

K18-4 (SMRG) - K18-3 (GND)

-40 to 80°C (-40 to 176°F)

25.0 to 59.0 Ω

(e) Reconnect the K18 HV battery junction block assembly connector.

(f) Install the No. 1 HV battery cover panel RH.

NG

GO TO STEP 19

OK

17.

CHECK HV BATTERY JUNCTION BLOCK ASSEMBLY (SMRG)

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) Remove the No. 1 HV battery cover panel RH.

Click here

(c) Disconnect the 2 HV floor under wire connectors from the HV battery junction block assembly.

(d) Disconnect the 2 HV battery high voltage connectors from the HV battery junction block assembly.

NOTICE:

Insulate each disconnected high-voltage connector with insulating tape. Wrap the connector from the wire harness side to the end of the connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

S3-1 (CEI) - y3-1 (-)

Power switch off

10 kΩ or higher

HINT:

  • If a system main relay is stuck closed, inspect the HV battery junction block assembly without removing it from the vehicle, in order to keep the relay closed.
  • If the result of reading the freeze frame data is A, the HV battery junction block assembly must be replaced. Measuring resistance can determine that this is either a present or past malfunction.

*a

Component without harness connected

(HV Battery Junction Block Assembly)

(f) Reconnect the 2 HV battery high voltage connectors.

(g) Reconnect the 2 HV floor under wire connectors.

(h) Install the No. 1 HV battery cover panel RH.

Result

Judgment

Proceed to

OK

Past malfunction

A

NG

Present malfunction

B

B

GO TO STEP 20

A

18.

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

Click here

NEXT

GO TO STEP 21

19.

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

Click here

NEXT

GO TO STEP 21

20.

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

Click here

NEXT

21.

CHECK HYBRID VEHICLE CONTROL ECU (CHECK FOR NORMAL OPERATION)

Click here

Result

Proceed to

Difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is always less than 100 V.

A

Difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is 100 V or more.

B

A

END

B

REPLACE HYBRID VEHICLE CONTROL ECU AND HV BATTERY JUNCTION BLOCK ASSEMBLY

    Hybrid/EV Battery Positive and Negative Contactor Actuator Stuck Closed (P0AA073)

    Hybrid/EV Battery Voltage System Isolation Internal Electronic Failure (P0AA649,P1C7C49-P1C7F49)

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