Toyota Avalon (XX50): EPB System Malfunction (C13AF). Reaction Force Pressure Sensor Zero Point Malfunction (C14B3). Servo Pressure Sensor Zero Point Malfunction (C14C3)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System(for Hv Model) / EPB System Malfunction (C13AF). Reaction Force Pressure Sensor Zero Point Malfunction (C14B3). Servo Pressure Sensor Zero Point Malfunction (C14C3)

EPB System Malfunction (C13AF)

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) is connected to the parking brake ECU (brake actuator assembly) via CAN communication. If an electric parking brake system malfunction occurs, this DTC is output.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C13AF	EPB System Malfunction	420	Electric parking brake system malfunction signal continues for 1 second.	Parking brake ECU (brake actuator assembly)	Does not come on	Brake hold DTC HINT: EPB: Electric Parking Brake System

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

Note

C13AF

EPB System Malfunction

420

Electric parking brake system malfunction signal continues for 1 second.

Parking brake ECU (brake actuator assembly)

Does not come on

Brake hold DTC

HINT:

EPB: Electric Parking Brake System

PROCEDURE

1.	CHECK DTC (ELECTRIC PARKING BRAKE SYSTEM)

(a) Check for electric parking brake system DTCs and record any codes that are output.

Chassis > Electric Parking Brake > Trouble Codes

INSPECT ELECTRIC PARKING BRAKE SYSTEM

Reaction Force Pressure Sensor Zero Point Malfunction (C14B3)

DESCRIPTION

The reaction force pressure sensor detects and outputs the brake fluid pressure of the stroke simulator, which changes in accordance with brake pedal operation, to the skid control ECU (brake booster with master cylinder assembly).

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C14B3	Reaction Force Pressure Sensor Zero Point Malfunction	204	When the brake pedal is not depressed, the reaction force pressure sensor output value is -0.63 MPa (-6.4 kgf/cm2, -91.4 psi) or less or 1.53 MPa (15.6 kgf/cm2, 222 psi) or more for 3 seconds or more.	Skid control ECU (brake booster with master cylinder assembly)	Comes on	INF Code 204: SAE Code C14B3 Electronically controlled brake system DTC

MONITOR DESCRIPTION

When the brake pedal is not operated and the value of the reaction force pressure sensor exceeds a specific value, or the value is less than a specific value for a certain amount of time, the skid control ECU (brake booster with master cylinder assembly) judges that the zero point of the reaction force pressure sensor is abnormal and illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs	C14B3: Reaction force pressure sensor exceeded learning limit
Required Sensors/Components(Main)	Brake actuator (brake booster with master cylinder assembly)
Required Sensors/Components(Related)	Brake pedal stroke sensor assembly Brake actuator (brake booster with master cylinder assembly) Stop light switch assembly
Frequency of Operation	Continuous
Duration	3 seconds
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	C0562 (Brake pedal stroke sensor assembly voltage circuit/open) C124B (Brake pedal stroke sensor assembly invalid data) C14B0 (Reaction force pressure sensor voltage circuit check) C14B1 (Reaction force pressure sensor lost communication) C14B2 (Reaction force pressure sensor internal malfunction) C14B4 (Reaction force pressure sensor intermittent/erratic) C14B5 (Reaction force pressure sensor invalid data) P057C, P05DD (Brake pedal stroke sensor assembly open circuit) P057D, P05DE (Brake pedal stroke sensor assembly circuit high) P057E, P05DF (Brake pedal stroke sensor assembly intermittent/erratic) P05E0 (Brake pedal stroke sensor assembly "1"/"2" correlation)
All of the following conditions are met	-
Brake pedal stroke sensor assembly circuit fail	Not detected
Reaction force pressure sensor circuit fail	Not detected
Brake	Off

TYPICAL MALFUNCTION THRESHOLDS

Reaction force pressure sensor

Less than -0.63 MPa (-6.4 kgf/cm2, -91.4 psi), or higher than 1.53 MPa (15.6 kgf/cm2, 222 psi)

COMPONENT OPERATING RANGE

All of the following conditions are met	-
Brake pedal stroke sensor assembly circuit fail	Not detected
Reaction force pressure sensor circuit fail	Not detected
Brake	Off
Reaction force pressure sensor	-0.63 MPa (-6.4 kgf/cm2, -91.4 psi) or more, and 1.53 MPa (15.6 kgf/cm2, 222 psi) or less

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off.
Turn the power switch on (IG).
Turn the Techstream on.
Wait 3 seconds.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here

HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

Click here

PROCEDURE

1.	CHECK BRAKE PEDAL

(a) Check that the brake pedal and the brake pedal stroke sensor assembly are properly installed and that the pedal can be depressed normally.

(b) Check and adjust the brake pedal height.

Click here

2.	READ VALUE USING TECHSTREAM (REACTION FORCE PRESSURE)

(a) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Reaction Force Pressure	Pressure value of stroke simulator	Min.: 0.00 MPa, Max.: 24.48 MPa	Brake pedal released: 0.00 MPa	Brake pedal is being depressed: Changes in proportion to the depression force of the brake pedal

Chassis > ABS/VSC/TRAC > Data List

Tester Display
Reaction Force Pressure

(b) Check that the reaction force pressure sensor output value is within 0.00 to 1.53 MPa when the brake pedal is not depressed.

OK:

The reaction force pressure sensor output value is within 0.00 to 1.53 MPa.

HINT:

If the reaction force pressure sensor output value is within 0.00 to 1.53 MPa, the skid control ECU (brake booster with master cylinder assembly) automatically performs zero point calibration every time the power switch is turned on (IG).

Therefore, if the reaction force pressure sensor output value is not within 0.00 to 1.53 MPa, replace the skid control ECU (brake booster with master cylinder assembly) with a new one.

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

3.	RECONFIRM DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

HINT:

Even if the DTC is cleared, it will immediately be output again if the reaction force pressure sensor zero point malfunction remains.

Result	Proceed to
DTC C14B3 is not output.	A
DTC C14B3 is output.	B

USE SIMULATION METHOD TO CHECK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

Servo Pressure Sensor Zero Point Malfunction (C14C3)

DESCRIPTION

The Servo pressure sensor detects and outputs the brake fluid pressure generated in the wheel cylinder according to the vehicle condition to the skid control ECU (brake booster with master cylinder assembly).

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C14C3	Servo Pressure Sensor Zero Point Malfunction	424	When the brake pedal is not depressed, the servo pressure sensor output value is -0.63 MPa (-6.4 kgf/cm2, -91.4 psi) or less or 1.53 MPa (15.6 kgf/cm2, 222 psi) or more for 3 seconds or more.	Skid control ECU (brake booster with master cylinder assembly)	Comes on	INF Code 424: SAE Code C14C3 Electronically controlled brake system DTC

MONITOR DESCRIPTION

When the brake pedal is not operated and the servo pressure sensor output value exceeds a specific value, or the value is less than a specific value for a certain amount of time, the skid control ECU (brake booster with master cylinder assembly) judges that the zero point of the servo pressure sensor is abnormal and illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs	C14C3: Servo pressure sensor exceeded learning limit
Required Sensors/Components(Main)	Brake actuator (brake booster with master cylinder assembly)
Required Sensors/Components(Related)	Brake pedal stroke sensor assembly Brake actuator (brake booster with master cylinder assembly) Stop light switch assembly
Frequency of Operation	Continuous
Duration	3 seconds
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	C0562 (Brake pedal stroke sensor assembly voltage circuit/open) C124B (Brake pedal stroke sensor assembly invalid data) C14B0 (Reaction force pressure sensor voltage circuit check) C14B1 (Reaction force pressure sensor lost communication) C14B2 (Reaction force pressure sensor internal malfunction) C14B3 (Reaction force pressure sensor exceeded learning limit) C14B4 (Reaction force pressure sensor intermittent/erratic) C14B5 (Reaction force pressure sensor invalid data) C14C0 (Servo pressure sensor voltage circuit check) C14C1 (Servo pressure sensor lost communication) C14C2 (Servo pressure sensor internal malfunction) C14C4 (Servo pressure sensor intermittent/erratic) C14C5 (Servo pressure sensor invalid data) P057C, P05DD (Brake pedal stroke sensor assembly open circuit) P057D, P05DE (Brake pedal stroke sensor assembly circuit high) P057E, P05DF (Brake pedal stroke sensor assembly intermittent/erratic) P05E0 (Brake pedal stroke sensor assembly "1"/"2" correlation)
All of the following conditions are met	-
Servo pressure sensor circuit fail	Not detected
Brake pedal stroke sensor assembly circuit fail	Not detected
Reaction force pressure sensor circuit fail	Not detected
Brake	Off

TYPICAL MALFUNCTION THRESHOLDS

Servo pressure sensor

Less than -0.63 MPa (-6.4 kgf/cm2, -91.4 psi), or higher than 1.53 MPa (15.6 kgf/cm2, 222 psi)

COMPONENT OPERATING RANGE

All of the following conditions are met	-
Servo pressure sensor circuit fail	Not detected
Brake pedal stroke sensor assembly circuit fail	Not detected
Reaction force pressure sensor circuit fail	Not detected
Brake	Off
Servo pressure sensor	-0.63 MPa (-6.4 kgf/cm2, -91.4 psi) or more, and 1.53 MPa (15.6 kgf/cm2, 222 psi) or less

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off.
Turn the power switch on (IG).
Turn the Techstream on.
Wait 3 seconds.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here

HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.

CAUTION / NOTICE / HINT

NOTICE:

Click here

PROCEDURE

1.	READ VALUE USING TECHSTREAM (SERVO PRESSURE)

(a) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Servo Pressure	Pressure value of servo	Min.: 0.00 MPa, Max.: 24.48 MPa	Brake pedal released: 0.00 to 2.10 MPa	Brake pedal is being depressed: Changes in proportion to the depression force of the brake pedal

Chassis > ABS/VSC/TRAC > Data List

Tester Display
Servo Pressure

(b) Check that the servo pressure sensor output value is within 0.00 to 1.53 MPa when the brake pedal not depressed.

OK:

The servo pressure sensor output value is within 0.00 to 1.53 MPa.

HINT:

If the servo pressure sensor output value is within 0.00 to 1.53 MPa, the skid control ECU (brake booster with master cylinder assembly) automatically performs zero point calibration every time the power switch is turned on (IG).

Therefore, if the servo pressure sensor output value is not within 0.00 to 1.53 MPa, replace the skid control ECU (brake booster with master cylinder assembly) with a new one.

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

2.	RECONFIRM DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

HINT:

Even if the DTC is cleared, it will immediately be output again if the servo pressure sensor zero point malfunction remains.

Result	Proceed to
DTC C14C3 is not output.	A
DTC C14C3 is output.	B

USE SIMULATION METHOD TO CHECK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

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