Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001A0E1
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 - 08/2020]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P1C8549; High Voltage Power Resource Internal Electronic Failure; 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]

DTC

P1C8549

High Voltage Power Resource Internal Electronic Failure

DESCRIPTION

The hybrid vehicle control ECU monitors the system internal operation, it will store a DTC and perform fail-safe control if it detects the following malfunction.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P1C8549

High Voltage Power Resource Internal Electronic Failure

Battery overcurrent or overload current occurs due to a malfunction in the high-voltage circuit between the hybrid system, battery and inverter.

(1 trip detection logic)
  • Hybrid vehicle control ECU
  • Battery voltage sensor
  • HV battery junction block assembly
  • Wire harness or connector

Does not come on

Master Warning Light:

Comes on

Related Data List

DTC No.

Data List

P1C8549
  • Hybrid Battery Current
  • Hybrid Battery Voltage
  • VL-Voltage before Boosting
  • VH-Voltage after 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 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): UTILITY

  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. Drive the vehicle for approximately 10 minutes according to the freeze frame data items "Vehicle Speed", "Accelerator Position" and "Hybrid Battery Current".
  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

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.

    *a

    Without waiting for 10 minutes

    Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): PRECAUTION

    HINT:

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

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 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

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

P1C8549 only is output.

A

DTCs other than P1C8549 is also output.

B

(e) Turn the power switch off.

B

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

A

2.

READ VALUE USING TECHSTREAM (HYBRID BATTERY CURRENT)

(a) Connect the Techstream to the DLC3.

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

(c) Enter the following menus: Powertrain / Hybrid Control / Data List / Hybrid Battery Current.

Powertrain > Hybrid Control > Data List

Tester Display

Hybrid Battery Current

(d) Read the Data List.

Result

Proceed to

The value of Hybrid Battery Current is between -4 A and 4 A

A

Other than above

B

(e) Turn the power switch off.

A

REPLACE HYBRID VEHICLE CONTROL ECU

B

3.

CHECK HARNESS AND CONNECTOR (BATTERY VOLTAGE SENSOR - 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 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HV BATTERY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL+

(c) Disconnect the y7 battery current sensor connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

(d) Remove the No. 1 hybrid battery exhaust duct.

Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HV BATTERY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL+

(e) Disconnect the y6 battery voltage sensor connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

(f) Measure the resistance according to the value(s) in the tables below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

y6-5 (IB0) - y7-4 (IB0)

Power switch off

Below 1 Ω

y6-12 (GIB) - y7-3 (GIB)

Power switch off

Below 1 Ω

y6-6 (VIB) - y7-1 (VIB)

Power switch off

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

y6-5 (IB0) or y7-4 (IB0) - Body ground and other terminals

Power switch off

10 kΩ or higher

y6-12 (GIB) or y7-3 (GIB) - Body ground and other terminals

Power switch off

10 kΩ or higher

y6-6 (VIB) or y7-1 (VIB) - Body ground and other terminals

Power switch off

10 kΩ or higher

HINT:

As the battery harness is not available as a supply part, if the harness cannot be repaired, replace the HV battery.

*a

Rear view of wire harness connector

(to Battery Voltage Sensor)

*b

Front view of wire harness connector

(to HV Battery Junction Block Assembly (Battery Current Sensor))

(g) Reconnect the y6 battery voltage sensor connector.

(h) Install the No. 1 hybrid battery exhaust duct.

(i) Reconnect the y7 battery current sensor connector.

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

NG

REPLACE HYBRID BATTERY THERMISTOR

OK

4.

CHECK HV BATTERY JUNCTION BLOCK ASSEMBLY (BATTERY CURRENT SENSOR (IB))

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 hybrid battery exhaust duct.

Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: HV BATTERY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL+

(c) Connect the cable to the negative (-) auxiliary battery terminal.

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

(e) Using a toyota electrical tester set to 40 V, measure the VIB voltage according to the value(s) in the table below.

Tester Connection

Switch Condition

y6-6 (VIB) - y6-12 (GIB)

Power switch on (IG)

NOTICE:

  • Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.
  • Be sure to set the toyota electrical tester to 40 V when performing this test.

*a

Component with harness connected

(Battery Voltage Sensor)

(f) Using a toyota electrical tester set to 4 V, measure the IB0 voltage according to the value(s) in the table below.

Tester Connection

Switch Condition

y6-5(IB0) - y6-12(GIB)

Power switch on (IG)

NOTICE:

Be sure to set the toyota electrical tester to 4 V when performing this test.

*a

Component with harness connected

(Battery Voltage Sensor)

(g) Compare the measured values of the IB0 terminal voltage and VIB terminal voltage using the following formula:

IB0 voltage - VIB Voltage / 2 = less than 0.081 V

IB0 voltage - VIB Voltage / 2 = -0.081 V or higher

Result

Proceed to

Within the specified range above

A

Other than above

B

(h) Turn the power switch off.

(i) Disconnect the cable from the negative (-) auxiliary battery terminal.

(j) Install the No. 1 hybrid battery exhaust duct.

HINT:

When the power switch is on (IG) the actual current will be approximately 0 A. The following graph shows the relation of the actual output voltage of the battery current sensor terminal IB0 and actual current used for DTC judgment.

B

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

A

5.

REPLACE BATTERY VOLTAGE SENSOR

Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; HYBRID / BATTERY CONTROL: BATTERY VOLTAGE SENSOR (for NICKEL METAL HYDRIDE BATTERY): REMOVAL

NEXT

6.

SIMULATION TEST

(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) Clear the DTCs and freeze frame data.

Powertrain > Hybrid Control > Clear DTCs

(e) Drive the vehicle on urban roads for approximately 10 minutes.

(f) Turn the power switch off and wait for 2 minutes or more.

(g) Turn the power switch on (IG) and wait for 30 seconds or more.

NEXT

7.

RECONFIRM 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) Read output DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

DTCs are not output

A

P1C8549 is output

B

(e) Turn the power switch off.

A

END
B

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY