Brake Control: Overview Lexus RX II рестайлинг

DESCRIPTION

Refer to «DTC C0200/31», «C0205/32».

DTCs C1273/73 and C1274/74 can be deleted when the speed sensor sends a vehicle speed signal or the test mode ends. DTCs C1273/73 and C1274/74 are output only in the test mode.

DIAGNOSTIC TROUBLE CODE CHART

HINT

1. DTC C0210/33 is for the right rear speed sensor.
2. DTC C0215/34 is for the left rear speed sensor.
3. The BRAKE warning light comes on when speed sensor malfunctions are detected in two or more wheels.

Scheme 1

When a fluid level drop in the master cylinder reservoir is detected, the signal is input to the skid control ECU.

When the DTC for the fluid level drop is memorized, the warning is canceled if the fluid level returns to normal and the other DTCs are not input.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 2

DIAGNOSTIC TROUBLE CODE CHART

DIAGNOSTIC TROUBLE CODE CHART

The skid control ECU inputs the steering angle sensor signal through the CAN communication. When a malfunction occurs in the communication line with the steering angle sensor, DTC U0126/63 (malfunction in communication with steering angle sensor) is output.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 3

The yaw rate and deceleration sensor detect any gravity applied to the vehicle and transmit the signal to the skid control ECU via CAN communication system (vehicle equipped with Enhanced VSC).

The deceleration sensor is built into the yaw rate and deceleration sensor and detects the vehicle condition in the 2 systems (GL1, GL2).

When a malfunction occurs in the communication line with the yaw rate sensor, DTC U0123/62 (yaw rate sensor communication malfunction) and DTC U0124/95 (deceleration sensor communication malfunction) are output.

DTCs C0371/71 and C1279/79 can be deleted when the yaw rate and deceleration sensor sends a yaw rate and/or acceleration signal or the Test Mode ends. DTCs C0371/71 and C1279/79 are output only in the Test Mode.

DIAGNOSTIC TROUBLE CODE CHART

These codes are memorized when the power source voltage for the skid control ECU drops or the voltage for the ABS No.1, ABS No.2 relay operation drops.

Codes may be memorized when the voltage of the auxiliary battery temporarily drops.

When the power source voltage is too high, the skid control ECU stops functioning and outputs no DTCs, and the ABS and BRAKE warning lights remain on.

HINT

DTC C1256/56 (accumulator low voltage malfunction) may be memorized if the power source voltage drops.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 4

Scheme 5

Scheme 6

The master cylinder pressure sensor and the wheel cylinder pressure sensor, which are built into the brake actuator, measure the master cylinder pressure and the wheel cylinder pressure and send to the skid control ECU.

DTC C1281/81 can be deleted when the master cylinder pressure sensor sends a master cylinder pressure signal or the Test Mode ends. DTC C1281/81 is output only in the Test Mode.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 7

The stroke sensor inputs the pedal stroke into the skid control ECU.

DTC C1346/71 can be deleted when the brake pedal stroke sensor sends a stroke sensor signal or the Test Mode ends. DTC C1346/71 is output only in the Test Mode.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 8

The skid control ECU inputs the stop light switch signal and detects braking condition.

The skid control ECU has a circuit for open detection inside. The skid control ECU outputs the DTC if it detects an open in the stop light signal input line when the stop light switch is off or an open in the stop light circuit (GND side).

DIAGNOSTIC TROUBLE CODE CHART

Scheme 9

The skid control ECU detects decreases in the accumulator pressure according to the data from the accumulator pressure sensor, and then starts and stops the pump motor by operating the motor relay.

The skid control ECU usually drives the motor relay 1 for Electronically Controlled Brake control, and the motor relay 2 for ABS control.

If either is malfunctioning, the will other substitute.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 10

The accumulator pressure sensor is built into the actuator and detects the accumulator pressure.

The skid control ECU turns on the brake control warning light and sounds the skid control buzzer if it senses a decrease in the accumulator pressure.

CONDITION CHART

The skid control ECU communicates with the HV control ECU and controls braking force according to the motor's regenerative force.

The skid control ECU sends enhanced VSC signal to the HV control ECU and inputs operating signal from the HV control ECU.

The skid control ECU uses CAN communication for communication with the HV control ECU. If a communication malfunction is memorized, the skid control ECU prohibits enhanced VSC operation and a part of Electronically Controlled Brake control by fail safe function.

C1259/59 is stored if the ignition switch on with the HV battery service plug disconnected.

DIAGNOSTIC TROUBLE CODE CHART

HINT

This DTC is output from the skid control ECU when the HV control ECU sends a malfunction signal to the skid control ECU.

The skid control ECU acquires steering angle sensor zero point every time the ignition switch is turned on and the vehicle is driven at 22 mph (35 km/h) or more for approximately 5 seconds. The ECU also stores the previous zero point.

If front wheel alignment or steering wheel position is adjusted without disconnecting the negative battery terminal, or if yaw rate and deceleration sensor zero point is not acquired after the adjustments have been completed, the skid control ECU detects the difference between the previous zero point and newly acquired zero point and outputs this DTC to indicate a poor adjustment.

Warning of the steering angle sensor zero point malfunction will be cancelled by turning the ignition switch off.

DIAGNOSTIC TROUBLE CODE CHART

The skid control ECU outputs this DTC if malfunctions are found in the circuit inside the computer by self-diagnosis.

DIAGNOSTIC TROUBLE CODE CHART

ABS main relay 1 (ABS No.1 relay) supplies power to the changeover solenoid and the linear solenoid.

ABS main relay 2 (ABS No.2 relay) goes on for approximately 5 seconds after the ignition switch is turned off and the braking effort signal input is terminated. ABS main relay 2 (ABS No.2 relay) supplies electricity and maintains operating condition for the brake system when the ignition switch is off.

DIAGNOSTIC TROUBLE CODE CHART

Each solenoid adjusts pressure which affects each wheel cylinder according to signals from the skid control ECU and controls the vehicle.

The master cut solenoid (SMC 1/2) is closed and blocks the master cylinder pressure from the Electronically Controlled Brake control pressure when the system is normal. The master cut solenoid is open and sends the master cylinder fluid pressure to the non-assisted brake wheel cylinders during the fail safe due to system malfunction.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 11

Scheme 12

The stroke simulator solenoid (SCSS) generates pedal reactive effort during Electronically Controlled Brake control. If one of the 4 wheels loses brake booster function, the stroke simulator operation is prohibited.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 13

The skid control ECU controls braking force according to the hybrid system regenerative braking force and inputs the fluid pressure necessary for operating each wheel cylinder according to the wheel cylinder pressure sensor.

DTCs may be stored if one of the following occurs

1. Brake fluid leaks
2. Wheel cylinder vibrates due to uneven wear of brake disc rotor
3. Foreign matter enters solenoid valve
4. Line pressure drops during air bleeding
5. Disc brake pad is replaced
6. Rotor is replaced

DIAGNOSTIC TROUBLE CODE CHART

The skid control ECU stores and corrects the difference in each individual part such as the stroke sensor, actuator solenoids, and stroke simulator solenoid. Perform initialization of linear solenoid valve and calibration if these parts are replaced.

The skid control ECU inputs the shift position P signal.

DIAGNOSTIC TROUBLE CODE CHART

The accumulator (ACC) pressure sensor is built into the brake actuator.

The skid control ECU detects the accumulator pressure from the data sent from the accumulator pressure sensor, and then runs and stops the pump motor by operating the motor relay.

DTCs may be output if the accumulator pressure drops due to frequent braking (this is not a malfunction).

DIAGNOSTIC TROUBLE CODE CHART

The brake control power supply assembly (capacitor) provides auxiliary power for brake control when an auxiliary battery (12 V) voltage drops.

DIAGNOSTIC TROUBLE CODE CHART

The brake control power supply assembly (capacitor) provides auxiliary power for brake control when an auxiliary battery (12 V) voltage drops.

The FAIL and ENA lines are placed between the skid control ECU and the brake control power supply assembly.

Signals indicating that the brake control power supply is in auxiliary mode are sent to the skid control ECU through the FAIL line.

Charge permit prohibition signals are sent to the brake control power supply through the ENA line.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 14

DTCs C0371/71 can be deleted when the yaw rate and deceleration sensor sends a yaw rate signal or the Test Mode ends. DTCs C0371/71 are output only in the Test Mode.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 15

Scheme 16

Scheme 17

1. CHECK HARNESS AND CONNECTOR (BETWEEN YAW RATE AND DECELERATION SENSOR AND IG CIRCUIT) Disconnect the yaw rate and deceleration sensor connector. Turn the ignition switch on. Measure the voltage according to the value(s) in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition Y1-5 (IG) - Body ground 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (BETWEEN YAW RATE AND DECELERATION SENSOR AND BODY GROUND) Disconnect the yaw rate and deceleration sensor connector. Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition Y1-1 (GND) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE YAW RATE AND DECELERATION SENSOR

The DTC is stored if a brake fluid, internal or other leak is detected due to improper sealing in the actuator. Internal leakage is suspected if the pump motor operates frequently without braking.

DIAGNOSTIC TROUBLE CODE CHART

The skid control ECU inputs the signals from the ECM, power steering (EPS) ECU, steering control (VGRS) ECU, steering angle sensor, and yaw rate and deceleration sensor via the CAN communication system.

DIAGNOSTIC TROUBLE CODE CHART

Scheme 18

The skid control ECU is connected to the combination meter via CAN and multiplex communications. If any of the following is detected, the ABS warning light remains on.

1. The skid control ECU connectors are disconnected from the skid control ECU.
2. There is a malfunction in the skid control ECU internal circuit.
3. There is an open in the harness between the combination meter and the skid control ECU. HINT: There is a case that the intelligent tester cannot be used when the skid control ECU is abnormal.

Scheme 19

The skid control ECU is connected to the combination meter via CAN and multiplex communications.

If any of the following is detected, the BRAKE warning light remains on

1. The skid control ECU connector is disconnected from the skid control ECU.
2. The brake fluid level is insufficient.
3. The parking brake is applied.
4. The EBD is defective.

Scheme 20

If the ECU stores a DTC, the brake control warning light comes on in the combination meter.

The skid control ECU is connected to the combination meter via CAN and multiplex communications.

Scheme 21

The skid control ECU is connected to the combination meter via CAN and multiplex communications.

The SLIP indicator blinks during VSC and/or TRAC operation.

When the system fails, the SLIP indicator comes on to warn the driver.

The SLIP indicator comes on when traction control is terminated by pressing the traction OFF switch.

The skid control buzzer sounds while the accumulator pressure is abnormally low or an abnormality causing low fluid pressure occurs, and then the VSC is activated.

Scheme 22

Connecting terminals TC and CG of the DLC3 causes the ECU to display the DTC by blinking the ABS warning light.

Scheme 23

In the sensor check mode, a malfunction of the speed sensor that cannot be detected when the vehicle is stopped is detected while driving.

Transition to the sensor check mode can be performed by connecting terminals TS and CG of the DLC3 and turning the ignition switch from off to ON position.

Scheme 24

Scheme 25

Scheme 26

1. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO DLC3 (TS)) Turn the ignition switch off. Disconnect the skid control ECU connector. Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition S39-32 (TS) - D1-12 (TS) Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (DLC3 (CG) TO BODY GROUND) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition D1-4 (CG) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (DLC3 (TS) TO BODY GROUND) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION CHART Tester Connection Specified Condition D1-12 (TS) - Body ground 10 kohms or higher HINT: If troubleshooting has been carried out according to the PROBLEM SYMPTOMS TABLE, refer back to the table and proceed to the next step before replacing the part (See «PROBLEM SYMPTOMS TABLE» ). NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SKID CONTROL ECU

Scheme 27

Scheme 28

Scheme 29

1. INSPECT BRAKE ACTUATOR ASSEMBLY OPERATION Pre-check preparation Move the shift lever to the P position. Apply the parking brake and connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position. Turn on the intelligent tester. Select "MAS CYL PRS1", "MAS CYL PRS2", "FR PRESS SENS", "FL PRESS SENS" and "RL PRESS SENS". Check FR system solenoids (SLA**, SLR**, SMC1, SMC2). Select "SLAFR CUR". --> Enter and check the output voltage. NOTE: Do not depress the brake pedal. HINT: It takes approximately 35 seconds to complete the check. If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» ) Standard voltage: VOLTAGE SPECIFICATION CHART Sensor 10 to 20 sec. after check start (V) 35 sec. or more after check start (V) MAS CYL PRS 1 0.3 to 0.7 0.3 to 0.7 MAS CYL PRS 2 0.3 to 0.7 0.3 to 0.7 FR PRESS SENS 2.5 to 4.5 0.3 to 0.7 FL PRESS SENS 0.3 to 0.7 0.3 to 0.7 RR PRESS SENS 0.3 to 0.7 0.3 to 0.7 RL PRESS SENS 0.3 to 0.7 0.3 to 0.7 Check FL system solenoids (SLA**, SLR**, SMC1, SMC2). Select "SLAFL CUR". --> Enter and check the output voltage. NOTE: Do not depress the brake pedal. HINT: It takes approximately 35 seconds to complete the check. If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» ) Standard voltage: VOLTAGE SPECIFICATION CHART Sensor 10 to 20 sec. after check start (V) 35 sec. or more after check start (V) MAS CYL PRS 1 0.3 to 0.7 0.3 to 0.7 MAS CYL PRS 2 0.3 to 0.7 0.3 to 0.7 FR PRESS SENS 0.3 to 0.7 0.3 to 0.7 FL PRESS SENS 2.5 to 4.5 0.3 to 0.7 RR PRESS SENS 0.3 to 0.7 0.3 to 0.7 RL PRESS SENS 0.3 to 0.7 0.3 to 0.7 Check RR system solenoids (SLA**, SLR**, SMC1, SMC2). Select "SLARR CUR". --> Enter and check the output voltage. NOTE: Do not depress the brake pedal. HINT: It takes approximately 35 seconds to complete the check. If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» ) Standard voltage: VOLTAGE SPECIFICATION CHART Sensor 10 to 20 sec. after check start (V) 35 sec. or more after check start (V) MAS CYL PRS 1 0.3 to 0.7 0.3 to 0.7 MAS CYL PRS 2 0.3 to 0.7 0.3 to 0.7 FR PRESS SENS 0.3 to 0.7 0.3 to 0.7 FL PRESS SENS 0.3 to 0.7 0.3 to 0.7 RR PRESS SENS 2.5 to 4.5 0.3 to 0.7 RL PRESS SENS 0.3 to 0.7 0.3 to 0.7 Check RL system solenoids (SLA**, SLR**, SMC1, SMC2). Select "SLAFL CUR". --> Enter and check the output voltage. NOTE: Do not depress the brake pedal. HINT: It takes approximately 35 seconds to complete the check. If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» ) Standard voltage: VOLTAGE SPECIFICATION CHART Sensor 10 to 20 sec. after check start (V) 35 sec. or more after check start (V) MAS CYL PRS 1 0.3 to 0.7 0.3 to 0.7 MAS CYL PRS 2 0.3 to 0.7 0.3 to 0.7 FR PRESS SENS 0.3 to 0.7 0.3 to 0.7 FL PRESS SENS 0.3 to 0.7 0.3 to 0.7 RR PRESS SENS 0.3 to 0.7 0.3 to 0.7 RL PRESS SENS 2.5 to 4.5 0.3 to 0.7 Check SMC1 and SMC2. Select and enter "ELECTRONICALLY CONTROLLED BRAKE SYSTEM INVALID" on the intelligent tester menu screen to prohibit the brake control. Check that the brake control warning light comes on. Check the output voltage by depressing the pedal. Standard Voltage: Difference in the output voltage between "MAS CYL PRS 1" and "FR PRESS SENS" is less than 0.4 V. Standard Voltage: Difference in the output voltage between "MAS CYL PRS 2" and "FL PRESS SENS" is less than 0.4 V. Enter the return key on the intelligent tester and cancel brake control prohibition (ELECTRONICALLY CONTROLLED BRAKE SYSTEM INVALID).
2. INSPECT PRESSURE SENSOR OPERATION Check the battery voltage Standard voltage: 10 to 14 V (during engine stop) Connect the hydro booster pressure gauge and pedal effort gauge. Install the hydro LSPV gauge (SST) and brake pedal effort gauge. SST 09709-29018 Bleed the air from the hydro booster pressure gauge. Move the shift lever to the P position. Connect the intelligent tester to the DLC3 with the parking brake applied. Turn the ignition switch to the ON position. Clear the DTC. Check the wheel cylinder pressure sensor and master pressure sensor. Turn on the intelligent tester. Select "MAS CYL PRS 1", "MAS CYL PRS 2", "FR PRESS SENS", "FL PRESS SENS", "RR PRESS SENS", and "RL PRES SENS". Check the brake pedal effort gauge, hydro booster pressure gauge reading, and output pressure voltage. If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» ) Standard voltage: VOLTAGE SPECIFICATION CHART Brake effort N (kgf, lbf) MAS CYL PRS 1 (V) MAS CYL PRS 2 (V) 200 (20.4, 45) 0.85 to 1.15 0.85 to 1.15 500 (51, 112) 1.85 to 2.15 1.85 to 2.15 VOLTAGE SPECIFICATION CHART Brake effort N (kgf, lbf) Front right wheel hydraulic pressure MPa (kgf/cm 2, psi) FR PRESS SENS (V) 50 (5.1, 11) 2.6 (26.5, 377) 0.85 to 1.15 100 (10.2, 22) 6.3 (64.3, 914) 1.6 to 1.9 150 (15.3, 34) 8.1 (82.6, 1175) 1.95 to 2.25 200 (20.4, 45) 8.2 (83.6, 1189) 2.0 to 2.3 VOLTAGE SPECIFICATION CHART Brake effort N (kgf, lbf) Front left wheel hydraulic pressure MPa (kgf/cm 2, psi) FL PRESS SENS (V) 50 (5.1, 11) 2.6 (26.5, 377) 0.85 to 1.15 100 (10.2, 22) 6.3 (64.3, 914) 1.6 to 1.9 150 (15.3, 34) 8.1 (82.6, 1175) 1.95 to 2.25 200 (20.4, 45) 8.2 (83.6, 1189) 2.0 to 2.3 VOLTAGE SPECIFICATION CHART Brake effort N (kgf, lbf) Rear right wheel hydraulic pressure MPa (kgf/cm 2, psi) RR PRESS SENS (V) 50 (5.1, 11) 2.7 (27.5, 392) 0.85 to 1.15 100 (10.2, 22) 5.0 (51.0,725) 1.35 to 1.65 150 (15.3, 34) 5.0 (51.0, 725) 1.35 to 1.65 200 (20.4, 45) 5.0 (51.0, 725) 1.35 to 1.65 VOLTAGE SPECIFICATION CHART Brake effort N (kgf, lbf) Rear left wheel hydraulic pressure MPa (kgf/cm 2, psi) RL PRESS SENS (V) 50 (5.1,11) 2.7 (27.5, 392) 0.85 to 1.15 100 (10.2, 22) 5.0 (51.0, 725) 1.35 to 1.65 150 (15.3, 34) 5.0 (51.0, 725) 1.35 to 1.65 200 (20.4, 45) 5.0 (51.0, 725) 1.35 to 1.65 Check the accumulator (ACC) pressure sensor. Move the shift lever to the P position. Apply the parking brake and connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position. Turn on the intelligent tester. Select and enter the accumulator (ACC) pressure sensor 1 ("ACC PRESS SENS") into the date monitor. Temporarily operate the pump motor by depressing the brake pedal 4 or 5 times. After confirming that the pump motor stops, check the pressure output voltage. Standard voltage: 2.6 to 3.8 V If incorrect, troubleshoot the brake system. (See «SYSTEM DIAGRAM» )

See also:
• DTC CHECK / CLEAR
• REMOVAL
• REMOVAL
• REMOVAL
• REMOVAL