Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000025DUH
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): C117A49,C137BA2; Brake System Control Module "A" System Voltage Line Internal Electronic Failure; 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]

DTC

C117A49

Brake System Control Module "A" System Voltage Line Internal Electronic Failure

DTC

C137BA2

Brake System Control Module "A" System Voltage System Voltage Low

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU (brake actuator assembly) stores this DTC and the fail-safe function prohibits ABS, brake assist, regenerative braking, etc. operation.

This DTC is stored when the +BS terminal voltage meets one of the DTC detection conditions due to a malfunction in the power supply or charging circuit such as the auxiliary battery or DC/DC converter circuit, etc.

The DTC is cleared when the +BS terminal voltage returns to normal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

DTC Output from

Note

C117A49

Brake System Control Module "A" System Voltage Line Internal Electronic Failure

The vehicle speed is 15 km/h (9 mph) or more and the +BS terminal voltage is 9.6 V or more, the skid control ECU (brake actuator assembly) turns on more than one valve at the same time within a short period of time and the valve relay supply voltage drop exceeds the threshold.*
  • Wire harness or connector
  • Skid control ECU (brake actuator assembly)

Comes on

Brake/EPB
  • SAE Code: C117A
  • Output ECU: Skid control ECU (brake actuator assembly)

C137BA2

Brake System Control Module "A" System Voltage System Voltage Low

Any of the following is detected:

  1. The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage (soft low voltage) is less than 9.6 V for 1 second or more.
  2. The vehicle speed is 6 km/h (4 mph) or more and the +BS terminal voltage (hard low voltage) is less than 6.9 V for 1 second or more.
  3. The +BS terminal voltage is less than 6.7 V and the skid control ECU (brake actuator assembly) judges that power supply voltage is abnormal for 0.06 seconds or more.
  4. When the system has started, the +BS terminal voltage is less than 5 V for 0.5 seconds or more.
  5. The +BS terminal voltage is less than 2.6 V for 0.2 seconds or more.
  • Wire harness or connector
  • Skid control ECU (brake actuator assembly)

Does not come on

Brake/EPB

Output ECU: Skid control ECU (brake actuator assembly)

*: The skid control ECU (brake actuator assembly) monitors the resistance of the power source line at the +BS terminal. A malfunction is detected when an abnormality occurs in the +BS terminal wire harness or its connection and the skid control ECU (brake actuator assembly) determines that the wiring resistance at the +BS terminal exceeds the standard resistance.

MONITOR DESCRIPTION

When the vehicle speed is more than a certain value, the supply voltage of the skid control ECU (brake actuator assembly) is a certain value or more, the brake pedal is not depressed, and the resistance of the solenoid supply voltage line exceeds a certain value a certain number of times, the skid control ECU (brake actuator assembly) illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs

C117A: Supply voltage line test

Required Sensors/Components(Main)

Skid control ECU (brake actuator assembly)

Required Sensors/Components(Related)

Speed sensor

Skid control ECU (brake actuator assembly)

Stop light switch assembly

Frequency of Operation

During initial checking

Duration

-

MIL Operation

Immediately

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs 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

TMC's intellectual property

-

CONFIRMATION DRIVING PATTERN

NOTICE:

When performing the normal judgment procedure, make sure that the driver door is closed and is not opened at any time during the procedure.

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.
  • When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON and turn the GTS on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the ignition switch off.
  5. Turn the ignition switch to ON (READY) and turn the GTS on.
  6. Drive the vehicle at 15 km/h (9 mph) or more for 1 second. [*]

    HINT:

    [*]: Normal judgment procedure.

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

  7. Enter the following menus: Chassis / Brake/EPB* / Utility / All Readiness.

    *: Electric Parking Brake System

  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, perform driving pattern again.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before performing troubleshooting, make sure to confirm that the auxiliary battery voltage is normal.

    Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

*a

Front view of wire harness connector

(to skid control ECU (Brake Actuator Assembly))

(b) Disconnect the A51 skid control ECU (brake actuator assembly) connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A51-30 (+BS) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

*a

Front view of wire harness connector

(to skid control ECU (Brake Actuator Assembly))

(b) Disconnect the A51 skid control ECU (brake actuator assembly) connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A51-1 (+BM) - Body ground

Always

11 to 14 V
OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR