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DTC C0049:74 [ELECTRONICALLY CONTROLLED BRAKE UNIT]

id0402c6017500

Outline

System malfunction location

Brake fluid leakage or trapped air

Detection condition

•  The electronically controlled brake unit detects that the brake fluid automatic filling did not finish within the specified time.

Fail-safe

Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)

Possible cause

•  Brake pipe and brake hose malfunction

―  Brake fluid leakage

•  Trapped air

•  Electronically controlled brake unit malfunction

―  Brake fluid leakage from linear actuator

―  Cavitation

System wiring diagram

Not applicable

Connector diagram

Not applicable

System malfunction location	Brake fluid leakage or trapped air
Detection condition	• The electronically controlled brake unit detects that the brake fluid automatic filling did not finish within the specified time.
Fail-safe	Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
Possible cause	• Brake pipe and brake hose malfunction ― Brake fluid leakage • Trapped air • Electronically controlled brake unit malfunction ― Brake fluid leakage from linear actuator ― Cavitation
System wiring diagram	Not applicable
Connector diagram	Not applicable

Diagnostic Procedure

Step

Inspection

Results

Action

1

INSPECT BRAKE PIPE AND BRAKE HOSE FOR BRAKE FLUID LEAKAGE

•  Perform the brake fluid leakage inspection for the brake pipe and brake hose.

•  Is there brake fluid leakage?

Yes

Repair or replace the malfunctioning location and perform the repair completion verification.

(See FRONT BRAKE HOSE REMOVAL/INSTALLATION [(E)].)

(See REAR BRAKE HOSE REMOVAL/INSTALLATION [(E)].)

No

Go to the next step.

2

INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT FOR BRAKE FLUID LEAKAGE

•  Remove the brake pedal and inspect the electronically controlled brake unit for brake fluid leakage.

•  Is there brake fluid leakage?

Yes

Repair or replace the malfunctioning location and perform the repair completion verification.

(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)

(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].)

No

Go to the next step.

3

VERIFY IF AIR IS TRAPPED IN BRAKE LINE

•  Select the following items from the initialization screen of the M-MDS.

1.  “Toolbox”

2.  “Work Support”

3.  “BRAKES”

4.  “Self-Diagnosing Brake Line”

•  Perform the Self-Diagnosing Brake Line according to the directions on the screen.

•  Is the result normal?

Yes

Go to the next step.

No

Bleed the air from the brake fluid according to the diagnostic result, and go to the repair completion verification.

(See BRAKE FLUID AIR BLEEDING [(E)].)

4

INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT FOR MALFUNCTION DEPENDING ON REPEATABILITY

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Perform the DTC inspection for the electronically controlled brake unit.
(See DTC INSPECTION.)

•  Is the same Pending DTC present?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction recurs, replace the electronically controlled brake unit, then go to the next step.
(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].)

(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)

No

Go to the next step.

Repair completion verification

VERIFY IF OTHER DTCs DISPLAYED

•  Perform the DTC inspection.
(See DTC INSPECTION.)

•  Are any DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

No

DTC troubleshooting completed.

Step	Inspection	Results	Action
1	INSPECT BRAKE PIPE AND BRAKE HOSE FOR BRAKE FLUID LEAKAGE • Perform the brake fluid leakage inspection for the brake pipe and brake hose. • Is there brake fluid leakage?	Yes	Repair or replace the malfunctioning location and perform the repair completion verification. (See FRONT BRAKE HOSE REMOVAL/INSTALLATION [(E)].) (See REAR BRAKE HOSE REMOVAL/INSTALLATION [(E)].)
1		No	Go to the next step.
2	INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT FOR BRAKE FLUID LEAKAGE • Remove the brake pedal and inspect the electronically controlled brake unit for brake fluid leakage. • Is there brake fluid leakage?	Yes	Repair or replace the malfunctioning location and perform the repair completion verification. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].)
2		No	Go to the next step.
3	VERIFY IF AIR IS TRAPPED IN BRAKE LINE • Select the following items from the initialization screen of the M-MDS. 1. “Toolbox” 2. “Work Support” 3. “BRAKES” 4. “Self-Diagnosing Brake Line” • Perform the Self-Diagnosing Brake Line according to the directions on the screen. • Is the result normal?	Yes	Go to the next step.
3		No	Bleed the air from the brake fluid according to the diagnostic result, and go to the repair completion verification. (See BRAKE FLUID AIR BLEEDING [(E)].)
4	INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT FOR MALFUNCTION DEPENDING ON REPEATABILITY • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the DTC inspection for the electronically controlled brake unit. (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the electronically controlled brake unit, then go to the next step. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)
4		No	Go to the next step.
Repair completion verification	VERIFY IF OTHER DTCs DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification		No	DTC troubleshooting completed.