Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001G797
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): C1203; ECM Communication Circuit; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

DTC

C1203

ECM Communication Circuit

DESCRIPTION

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

Note

C1203

ECM Communication Circuit

1161

Either of the following is detected:

  1. Identification information sent from other ECUs does not match with the value stored when shipped from the factory.
  2. Identification information sent from other ECUs is not stored when shipped from the factory.
  • Other ECUs are not installed correctly
  • Skid control ECU (brake booster with master cylinder assembly)

Comes on
  • INF Code 1161: SAE Code C124A
  • Electronically controlled brake system DTC

HINT:

  • DTC C1203 (INF code 1161) is cleared when the conditions return to normal.
  • This DTC is stored when incorrect identification information is detected and is not due to an ECM communication error.

NOTICE:

DTC C1203 is output when an incorrect ECU is installed. If initialization is performed and learning occurs with an incorrect ECU installed, operations and functions will differ from those stored when the vehicle was shipped from the factory. Therefore, make sure that learning occurs properly.

MONITOR DESCRIPTION

When the vehicle is being driven, if the vehicle information, drive type or steering wheel position cannot be confirmed, the memorized data does not match or other related information cannot be stored such as when the ECU that was installed when the vehicle left the factory is changed or the EEPROM is malfunctioning, the skid control ECU (brake booster with master cylinder assembly) illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs

C124A: CAN communication identification signal

Required Sensors/Components(Main)

Skid control ECU (brake booster with master cylinder assembly)

Required Sensors/Components(Related)

Skid control ECU (brake booster with master cylinder assembly)

Speed sensor

Frequency of Operation

Continuous

Duration

-

MIL Operation

Immediately

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

EEPROM read-in

Complete

IG1

On

Vehicle speed

40 km/h (25 mph) or more

TYPICAL MALFUNCTION THRESHOLDS

Both of the following conditions are met

A and B

A. Test Mode

Off

B. One of the following conditions is met

-

Grade info

Undetermined or different from a storage memory

Drive train info

Undetermined or different from a storage memory

Steering info

Undetermined or different from a storage memory

Car spec info

There is no write-in

COMPONENT OPERATING RANGE

All of the following conditions are met

-

EEPROM read-in

Complete

IG1

On

Test Mode

Off

Grade info

Decision and concordance from a storage memory

Drive train info

Decision and concordance from a storage memory

Steering info

Decision and concordance from a storage memory

Car spec info

There is write-in

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Turn the power switch on (IG).
  3. Turn the Techstream on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the power switch off.
  6. Turn the power switch on (READY).
  7. Turn the Techstream on.
  8. Confirm that the vehicle is not in Test Mode and drive the vehicle at a speed of 40 km/h (25 mph) or more for 1 minute.
  9. Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
  10. Read the DTCs.

    HINT:

    • If a DTC is output, the system is malfunctioning.
    • If a DTC is not output, perform the following procedure.
  11. If the DTCs are not output, perform a universal trip and check for permanent DTCs.

    Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTCs are output, the system is normal.

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): INITIALIZATION

PROCEDURE

1.

CHECK PART NUMBER

(a) Check that the proper hybrid vehicle control ECU and main body ECU (multiplex network body ECU) are installed.

OK:

Proper ECUs are installed.

(b) Check if the hybrid vehicle control ECU and main body ECU (multiplex network body ECU) were replaced before the DTC was recorded.

OK:

ECUs were not replaced.

Result

Proceed to

OK

A

NG (A proper hybrid vehicle control ECU is not installed and/or the hybrid vehicle control ECU was replaced.)

B

NG (A proper main body ECU (multiplex network body ECU) is not installed and/or the main body ECU (multiplex network body ECU) was replaced.)

C
B

REPLACE HYBRID VEHICLE CONTROL ECU 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID VEHICLE CONTROL ECU: REMOVAL

C

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL

A

2.

PERFORM INITIALIZATION

(a) Perform linear solenoid valve offset learning, ABS holding solenoid valve learning and system information memorization.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): INITIALIZATION

Chassis > ABS/VSC/TRAC > Utility

Tester Display

ECB Utility

(b) Perform yaw rate and acceleration sensor zero point calibration.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): CALIBRATION

Chassis > ABS/VSC/TRAC > Utility

Tester Display

Test Mode

HINT:

  • After installing a new skid control ECU (brake booster with master cylinder assembly), before performing linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization, DTC C1203 will be output.
  • If linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization are not performed, DTC C1203 will be output after the data stored in the skid control ECU (brake booster with master cylinder assembly) is cleared by performing "Reset Memory" using Techstream.
NEXT

3.

RECONFIRM DTC

(a) Clear the DTCs.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

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

(d) Check if the same DTC is output.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

Chassis > ABS/VSC/TRAC > Trouble Codes

Result

Proceed to

DTC C1203 is output.

A

DTC C1203 is not output.

B
A

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

B

END