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DTC C0049:4B [ELECTRONICALLY CONTROLLED BRAKE UNIT]

id0402c6017400

Outline

System malfunction location

Brake fluid leakage or trapped air

Detection condition

•  The electronically controlled brake unit detects trapped air caused by an increase in the brake fluid temperature.

Fail-safe

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

Possible cause

•  Brake fluid deterioration

•  Trapped air

•  High temperature in brakes/brake fluid

•  Electronically controlled brake unit malfunction

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 trapped air caused by an increase in the brake fluid temperature.
Fail-safe	Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
Possible cause	• Brake fluid deterioration • Trapped air • High temperature in brakes/brake fluid • Electronically controlled brake unit malfunction
System wiring diagram	Not applicable
Connector diagram	Not applicable

Diagnostic Procedure

Step

Inspection

Results

Action

1

VERIFY BRAKE FLUID DETERIORATION

•  Visually inspect the color of the brake fluid.

•  Is the color of the brake fluid nearly transparent?

Yes

Go to the next step.

No

Perform air bleeding after adding new brake fluid, and then perform the repair completion verification.

2

VERIFY IF AIR IS TRAPPED IN BRAKE LINE

•  Switch the ignition OFF and allow the brakes to cool down for a while.

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

•  Perform the work of depressing the brake pedal for 3 s or more and then releasing it for 5 times or more with the ignition switched ON (engine off or on).

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

•  Is the same Pending DTC present?

Yes

Bleed the air from the brake fluid and go to the repair completion verification.

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

No

System is normal. (Explain to the customer that a DTC was displayed due to the high temperature of the brake discs from repeated sudden braking (such as when driving on a circuit).)

Go to repair completion verification 2.

Repair completion verification 1

VERIFY THAT VEHICLE IS REPAIRED

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

•  Perform the work of depressing the brake pedal for 3 s or more and then releasing it for 5 times or more with the ignition switched ON (engine off or on).

•  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 2

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	VERIFY BRAKE FLUID DETERIORATION • Visually inspect the color of the brake fluid. • Is the color of the brake fluid nearly transparent?	Yes	Go to the next step.
1		No	Perform air bleeding after adding new brake fluid, and then perform the repair completion verification.
2	VERIFY IF AIR IS TRAPPED IN BRAKE LINE • Switch the ignition OFF and allow the brakes to cool down for a while. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the work of depressing the brake pedal for 3 s or more and then releasing it for 5 times or more with the ignition switched ON (engine off or on). • Perform the DTC inspection for the electronically controlled brake unit. (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Bleed the air from the brake fluid and go to the repair completion verification. (See BRAKE FLUID AIR BLEEDING [(E)].)
2		No	System is normal. (Explain to the customer that a DTC was displayed due to the high temperature of the brake discs from repeated sudden braking (such as when driving on a circuit).) Go to repair completion verification 2.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the work of depressing the brake pedal for 3 s or more and then releasing it for 5 times or more with the ignition switched ON (engine off or on). • 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.].)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	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 2		No	DTC troubleshooting completed.