Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001GCM3
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 04/2020]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P1C8449; High Voltage Power Resource Circuit Short during Ready ON; 2020 MY Corolla Corolla HV [01/2019 - 04/2020]

DTC

P1C8449

High Voltage Power Resource Circuit Short during Ready ON

DTC SUMMARY

MALFUNCTION DESCRIPTION

The hybrid vehicle control ECU monitors the high-voltage wiring between the HV battery and inverter with converter assembly and detects an open circuit malfunction.

HINT:

  • This DTC is differentiated from P300449 based on detection timing (after power switch is turned on (READY)). If P300449 is also output at the same time, first perform troubleshooting for P300449.
  • If there is a SMRG stuck open malfunction, only P1C8449 is output.

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

Inverter voltage sensor (VH or VL) internal circuit malfunction

  • Voltage sensor (VH or VL) malfunction
  • Motor generator control ECU (MG ECU) malfunction
  • Communication (wire harness) malfunction

High voltage system malfunction

  • HV battery malfunction
  • HV battery junction block assembly malfunction
  • Inverter with converter assembly malfunction
  • High-voltage wire harness malfunction
  • High-voltage connector or connection 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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P0AE411; Hybrid/EV Battery Precharge Contactor Circuit Short to Ground+

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P1C8449

High Voltage Power Resource Circuit Short during Ready ON

High-voltage circuit malfunctions between the HV battery and inverter with converter assembly.

When the power switch is on (READY), both "VL-Voltage before Boosting" and "VH-Voltage after Boosting" drop abnormally.

The EV electric battery fuse is blown, the service plug grip is removed, SMRB or SMRG remains open, or the high-voltage cable has an open circuit.

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

Does not come on

Master Warning: Comes on

Related Data List

DTC No.

Data List

P1C8449
  • Hybrid/EV Battery Voltage
  • Hybrid/EV Battery Current
  • VL-Voltage before Boosting
  • VH-Voltage after Boosting

The following items can be helpful when performing repairs:

Data List

  • Ready Signal

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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; 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. 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/EV Battery Voltage" and "VL-Voltage before Boosting" for 3 minutes. If the difference between "Hybrid/EV Battery Voltage" and "VL-Voltage before Boosting" is always less than 50 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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): HV Battery High-voltage Line Circuit+

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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; 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.

    *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.

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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

P1C8449 only is output, or P0A9563 and 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

P0A9563 is also output.

D

Malfunction Content

System

Relevant DTC

Microcomputer malfunction

Hybrid control system

P0A1B49

Drive Motor "A" Control Module Internal Electronic Failure

P060647

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

Motor generator control system

P0A1B1F

Generator Control Module Circuit Intermittent

P0A1A47

Generator Control Module Watchdog / Safety MC 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

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

Motor generator control system

P06D61C

Generator Control Module Offset Power 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

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

P0E311C

Boosting Converter Voltage Sensor "A" Voltage Out of Range

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

P0CA300

DC/DC Converter Step Up Voltage Performance

HINT:

  • P1C8449 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)

D

GO TO DTC CHART (P0A9563)

A

2.

CLEAR DTC

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NEXT

3.

CHECK DTC OUTPUT (HYBRID CONTROL)

(a) Connect the Techstream to the DLC3.

(b) With the vehicle stopped, apply the parking brake and turn the power switch on (READY).

NOTICE:

Perform this test with the AUTO function (shift-linked function) of the electronic parking brake system off.

HINT:

  • If the power switch could not be turned on (READY), turn the power switch off and check for DTCs after turning the power switch on (READY) again.
  • When the parking brake indicator (red) is illuminated after the electric parking brake switch (electric parking brake switch assembly) has been pulled to the lock side, the maximum amount of braking force is applied if the electric parking brake switch (electric parking brake switch assembly) is pulled to the lock side one more time.
  • Because P300449 uses 2 trip detection logic, the DTC detection conditions need to be met 2 times.

(c) Ensure the safety of the areas in front and at the back of the vehicle.

(d) Move the shift lever to D and depress both the accelerator pedal and brake pedal at the same time.

HINT:

Depressing both the accelerator pedal and brake pedal at the same time causes the HV battery current to flow and ensures that there is no problem with the high-voltage wiring.

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

(f) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

P1C8449 is output, or no DTCs are output.

A

Power switch could not be turned on (READY) and DTC P300449 is output.

B

(g) Turn the power switch off.

B

GO TO DTC CHART (P300449)

A

4.

CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P056014; System Voltage (BATT) Circuit Short to Ground or Open+

NG

CONNECT SECURELY
OK

5.

CHECK CONNECTOR CONNECTION CONDITION (FLOOR WIRE CONNECTOR)

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P0AA000; Hybrid/EV Battery Positive Contactor Circuit Stuck Closed+

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
B

CONNECT SECURELY
C

REPAIR OR REPLACE HARNESS OR CONNECTOR
A

6.

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

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY): P0AA000; Hybrid/EV Battery Positive Contactor Circuit Stuck Closed+

NG

CONNECT SECURELY
OK

7.

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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HV BATTERY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL+

(c) Disconnect the O35 HV battery junction block assembly connector.

(d) Disconnect the I2 hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I2-16 (SMRB) - O35-1 (SMRB)

Power switch off

Below 1 Ω

I2-13 (SMRG) - O35-4 (SMRG)

Power switch off

Below 1 Ω

*a

Front 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 I2 hybrid vehicle control ECU connector.

(g) Reconnect the O35 HV battery junction block assembly connector.

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

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

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

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 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HV BATTERY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL+

(c) Disconnect the O35 HV battery junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O35-3 (GND) - Body ground

Power switch off

Below 1 Ω

*a

Front view of wire harness connector

(to HV Battery Junction Block Assembly)

(e) Reconnect the O35 HV battery junction block assembly connector.

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

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

9.

REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; HYBRID / BATTERY CONTROL: HV RELAY ASSEMBLY (for NICKEL METAL HYDRIDE BATTERY): REMOVAL

NEXT

10.

CHECK HYBRID VEHICLE CONTROL ECU (CHECK FOR NORMAL OPERATION)

CAUTION:

Be sure to wear insulated gloves.

(a) Install the service plug grip.

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

(c) Clear the DTCs.

Powertrain > Hybrid Control > Clear DTCs

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

(e) Turn the power switch on (READY).

(f) Enter the following menus: Powertrain / Hybrid Control / Data List / VL-Voltage before Boosting, Hybrid/EV Battery Voltage.

Powertrain > Hybrid Control > Data List

Tester Display

VL-Voltage before Boosting

Hybrid Battery Voltage

(g) According to the display on the Techstream, read the Data List and monitor the values of "Hybrid/EV Battery Voltage" and "VL-Voltage before Boosting" for 3 minutes.

Result

Proceed to

Difference between "Hybrid/EV Battery Voltage" and "VL-Voltage before Boosting" is always less than 50 V.

A

Difference between "Hybrid/EV Battery Voltage" and "VL-Voltage before Boosting" is 50 V or more.

B

(h) Turn the power switch off.

A

END
B

REPLACE HYBRID VEHICLE CONTROL ECU