Last Modified: 02-14-2025 6.11:8.1.0 Doc ID: RM100000001EAAS
Model Year Start: 2019 Model: RAV4 Prod Date Range: [11/2018 -           ]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster): C137BA2; Brake System Control Module "A" System Voltage System Voltage Low; 2019 - 2025 MY RAV4 RAV4 HV [11/2018 -        ]

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 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 battery or alternator circuit, etc.

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

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

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. 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.*
  5. When the system has started, the +BS terminal voltage is less than 5 V for 0.5 seconds or more.
  6. The +BS terminal voltage is less than 2.6 V for 0.2 seconds or more.
  • Battery
  • Charging system
  • Internal power supply circuit of the 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.

DTC Detection Conditions: C137BA2

 

Vehicle Condition

Pattern 1

Pattern 2

Pattern 3

Pattern 4

Pattern 5

Pattern 6

Diagnosis Condition

The vehicle speed is 6 km/h (4 mph) or more.

○

○

-

-

-

-

The vehicle speed is 15 km/h (9 mph) or more and the +BS terminal voltage is 9.6 V or more.

-

-

-

○

-

-

The system has started.

-

-

-

-

○

-

Malfunction Status

The +BS terminal voltage (soft low voltage) is less than 9.6 V.

○

-

-

-

-

-

The +BS terminal voltage (hard low voltage) is less than 6.9 V.

-

○

-

-

-

-

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.

-

-

○

-

-

-

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.*

-

-

-

○

-

-

The +BS terminal voltage is less than 5 V.

-

-

-

-

○

-

The +BS terminal voltage is less than 2.6 V.

-

-

-

-

-

○

Detection Time

1 second or more.

1 second or more.

0.06 seconds or more.

-

0.5 seconds or more.

0.2 seconds or more.

Number of Trips

1 trip

1 trip

1 trip

1 trip

1 trip

1 trip

*: 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.

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

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 battery voltage is normal.

    Click here 2019 - 2025 MY RAV4 RAV4 HV [11/2018 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

  • After replacing the skid control ECU (brake actuator assembly), perform acceleration sensor zero point calibration and store system information memorization.

    Click here 2019 - 2025 MY RAV4 RAV4 HV [11/2018 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster): UTILITY

PROCEDURE

1.

CHECK FREEZE FRAME DATA (BS1 VOLTAGE VALUE AND MOTOR POWER SUPPLY VOLTAGE)

(a) Select a DTC to display the Freeze Frame Data.

(b) Read the freeze frame data of DTC C137BA2.

Chassis > Brake/EPB

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

BS1 Voltage Value

+BS terminal voltage value (value detected by ECU)

Min.: 0.0 V, Max.: 25.5 V

Ignition switch ON: 11.0 to 14.0 V

Changes in proportion to battery voltage

HINT:

This is the voltage detected at terminal +BS (which supplies power to each solenoid) of the skid control ECU (brake actuator assembly)

Motor Power Supply Voltage

+BM terminal voltage value (value detected by ECU)

Min.: 0.0 V, Max.: 25.5 V

Ignition switch ON: 11.0 to 14.0 V

Changes in proportion to battery voltage

HINT:

This is the voltage detected at terminal +BM (which supplies power to the ABS motor) of the skid control ECU (brake actuator assembly)

Chassis > Brake/EPB > DTC(C137BA2) > Freeze Frame Data

Tester Display

BS1 Voltage Value

Motor Power Supply Voltage

Result

Proceed to

BS1 Voltage Value and Motor Power Supply Voltage are less than 9.6 V.

A

Only BS1 Voltage Value is less than 9.6 V.

B

Only Motor Power Supply Voltage is less than 9.6 V, or both BS1 Voltage Value and Motor Power Supply Voltage are 9.6 V or more.

C
A

CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY 2019 - 2023 MY RAV4 [11/2018 - 10/2023]; A25A-FKS (BATTERY / CHARGING): CHARGING SYSTEM: ON-VEHICLE INSPECTION 2024 - 2025 MY RAV4 [10/2023 -        ]; A25A-FKS (BATTERY / CHARGING): CHARGING SYSTEM: ON-VEHICLE INSPECTION

C

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B

2.

READ VALUE USING GTS (BS1 VOLTAGE VALUE)

(a) Start the engine.

(b) Follow the instructions on the screen to display the Data List, and perform the inspection.

Chassis > Brake/EPB > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

BS1 Voltage Value

+BS terminal voltage value (value detected by ECU)

Min.: 0.0 V, Max.: 25.5 V

Ignition switch ON: 11.0 to 14.0 V

Changes in proportion to battery voltage

HINT:

This is the voltage detected at terminal +BS (which supplies power to each solenoid) of the skid control ECU (brake actuator assembly)

Chassis > Brake/EPB > Data List

Tester Display

BS1 Voltage Value

Result

Proceed to

The value of BS1 Voltage Value is 9.6 V or more.

A

The value of BS1 Voltage Value is less than 9.6 V.

B
A

USE SIMULATION METHOD TO CHECK

B

3.

CHECK HARNESS AND CONNECTOR (+BS 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 A39 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

A39-30 (+BS) - Body ground

Always

9.6 V or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (GND1 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.

(b) Disconnect the A39 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 resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A39-46 (GND1) - Body ground

1 minute or more after disconnecting the cable from the negative (-) battery terminal

Below 1 Ω
OK

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NG

REPAIR OR REPLACE HARNESS OR CONNECTOR