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 1.

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 1.

(See BRAKE FLUID AIR BLEEDING.)

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.)

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.)

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 1.
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 1. (See BRAKE FLUID AIR BLEEDING.)
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.) 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.)
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.