Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Brake System Control Module "A" System Voltage System Voltage High (C137BA3)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System / Brake System Control Module "A" System Voltage System Voltage High (C137BA3)

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 deviates 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

C137BA3

Brake System Control Module "A" System Voltage System Voltage High

The +BS terminal voltage is 17.4 V or more for 0.8 seconds or more.
  • Battery
  • Charging system
  • Wire harness and connector
  • Skid control ECU (Brake actuator assembly)

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • After replacing the skid control ECU (brake actuator assembly), perform "Calibration".

    Click here

PROCEDURE

1.

CHECK BATTERY

(a) Check the battery voltage.

Standard Voltage:

Tester Connection

Condition

Specified Condition

Positive (+) terminal - Negative (-) terminal

Always

11 to 14 V
NG

CHECK OR REPLACE CHARGING SYSTEM OR BATTERY

OK

2.

CHECK HARNESS AND CONNECTOR (+BS TERMINAL)

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

OK:

The connector is securely connected.

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

(b) Disconnect the A41 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

A41-14 (+BS) - Body ground

Always

11 to 14 V

A41-14 (+BS) - A41-1 (GND1)

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CLEAR DTC

(a) Reconnect the A41 skid control ECU (brake actuator assembly) connector.

(b) Connect the Techstream to the DLC3.

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

(d) Operate the Techstream to clear the codes. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Clear DTCs

(e) Press the DTC clear button.

(f) Turn the engine switch off.

NEXT

4.

RECONFIRM DTC

(a) Start the engine.

(b) Perform a road test.

(c) Read the DTCs following the prompts on the Techstream. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Trouble Codes

(d) Check if the same DTC is output.

Result

Proceed to

DTC C137BA3 is not output.

A

DTC C137BA3 is output.

B
A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

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