Electronically Controlled Brake (Diagnostics - Introduction): Other Lexus HS I

PRECAUTION

1. TROUBLESHOOTING PRECAUTIONS When there is a malfunction with terminal contact points or part installation problems, removal and installation of the suspected problem parts may return the system to the normal condition either completely or temporarily. In order to determine the malfunctioning area, be sure to check the conditions at the time the malfunction occurred, such as DTC output and the Freeze Frame Data, and record it before disconnecting each connector or removing and installing parts. Since the system may be influenced by malfunctions in systems other than the brake control system, be sure to check for DTCs in other systems.
2. HANDLING PRECAUTIONS Do not remove or install electronically controlled brake system parts such as the steering angle sensor, yaw rate and acceleration sensor or brake pedal stroke sensor except when required, as they cannot be adjusted correctly after removal or installation. Be sure to perform preparation before work and confirmation after work is completed by following the directions in the repair service information when working on the electronically controlled brake system. Be sure that the power switch is off when removing and installing the ECU, actuator, each sensor, etc. unless it is specified otherwise in the inspection procedure. If the brake booster with master cylinder (skid control ECU and brake actuator) or a sensor has been removed and installed, it is necessary to check the system for problems after the parts have been reassembled. Check for DTCs using the Techstream, also check that system functions and signals received by the ECU are normal using Test Mode. If the brake pedal is depressed before the brake control system is prepared to operate, the pedal stroke may seem unusually long or short. This is due to the fact the stroke simulator cut solenoid has not yet operated and is not a malfunction. After the power switch is turned on (IG) or the brake pedal is depressed twice or more, the stroke simulator will operate and the brake pedal stroke will remain consistent.
3. DTC PRECAUTION Warnings for some DTCs cannot be cleared only by repairing the malfunctioning parts. If the warning is displayed even after repair work, the DTC should be cleared after turning the power switch off. NOTE: If a DTC part is still malfunctioning even after the DTC is cleared, the DTC will be stored again.
4. CHASSIS DYNAMOMETER PRECAUTION Enter Inspection Mode to disable TRAC and VSC control when using a chassis dynamometer. Refer to «INSPECTION MODE PROCEDURE»(ref-398089-S21258796492011051600000) . NOTE: Make sure that the slip indicator lights blink (Inspection Mode is activated). Secure the vehicle with a lock chain for safety. When performing procedures related to VSC OFF switch operation, make sure that the mode is VSC off mode.
5. CAN COMMUNICATION SYSTEM PRECAUTIONS The CAN communication system is used for the data communication between the skid control ECU, the steering angle sensor, yaw rate and acceleration sensor and other ECUs. If there are any problems in the CAN communication line, corresponding DTCs in the communication line are stored. If any CAN communication line DTCs are output, repair the malfunction in the communication line and troubleshoot the electronically controlled brake system when data communication is normal. In order to enable CAN communication, a specific type of wiring is used for the CAN communication lines. The wiring used for each communication line is a twisted pair of wires that have an equal length. A bypass wire should not be used, because the data being transmitted will be corrupted.

Scheme 7

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Scheme 10

CHECK FOR INTERMITTENT PROBLEMS

1. CHECK FOR INTERMITTENT PROBLEMS HINT: A momentary interruption (open circuit) in the connectors and/or wire harnesses between the sensors and ECUs can be detected using the ECU Data List function of the Techstream. Turn the power switch off. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Follow the directions on the Techstream to display the Data List and select areas where momentary interruptions should be monitored. HINT: A momentary interruption (open circuit) cannot be detected for 3 seconds after the power switch is turned on (IG) (initial check). If the Error display remains displayed, check for continuity between the ECUs and the sensors, or between ECUs. The Error display on the Techstream will remain displayed for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition. ABS/VSC/TRAC Tester Display Measurement Item/Range Normal Condition Diagnostic Note FR Speed Open Front speed sensor RH open detection / Error or Normal Error: Momentary interruption Normal: Normal - FL Speed Open Front speed sensor LH open detection / Error or Normal Error: Momentary interruption Normal: Normal - RR Speed Open Rear speed sensor RH open detection / Error or Normal Error: Momentary interruption Normal: Normal - RL Speed Open Rear speed sensor LH open detection / Error or Normal Error: Momentary interruption Normal: Normal - Yaw Rate Open Yaw rate sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - Deceleration Open Acceleration sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - Steering Open Steering angle sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - Master Cylinder Open Regulator pressure sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - Stroke Open Brake pedal stroke sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - FR Wheel Cylinder Open Wheel cylinder pressure sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - Accumulator Open Accumulator pressure sensor open detection / Error or Normal Error: Momentary interruption Normal: Normal - HV Communication Open Hybrid vehicle communication open detection / Error or Normal Error: Momentary interruption Normal: Normal - While observing the screen, gently jiggle the connectors or wire harnesses between the ECUs and sensors, or between ECUs. OK Normal display appears. HINT: If the display changes, this indicates that there has been a momentary interruption (open circuit) in the connector and/or wire harness. In this case, repair or replace the connectors and/or wire harnesses as one of them is faulty.

Scheme 11

1. DESCRIPTION Perform initialization and calibration of the linear solenoid valve when the brake booster with master cylinder (skid control ECU, brake actuator or pressure sensor), brake pedal stroke sensor or brake pedal is replaced. Follow the procedure to perform initialization. HINT: If there is a problem with the auxiliary battery (12 V) voltage, initialization and calibration of the linear solenoid valve cannot be completed normally. Make sure to check the auxiliary battery voltage before performing initialization and calibration of the linear solenoid valve. If the actuator's temperature is high, initialization and calibration of the linear solenoid valve may not be completed normally. If so, wait until the temperature decreases and then perform initialization and calibration of the linear solenoid valve. If the power switch is turned off, brake pedal is depressed, parking brake is applied or vehicle speed signal is input while the linear solenoid valve offset learning is being performed, the learning will be cancelled. Part to be Replaced Necessary Operation Brake booster with master cylinder (Skid control ECU, brake actuator or pressure sensor) Initialization and calibration of the linear solenoid valve Brake pedal stroke sensor Brake pedal Clearing stored linear solenoid valve calibration data Initialization and calibration of the linear solenoid valve
2. PERFORM INITIALIZATION AND CALIBRATION OF LINEAR SOLENOID VALVE (When Using the Techstream) NOTE: If the brake control has been disabled, or the brake pedal stroke sensor or brake pedal has been replaced, it is necessary to perform linear solenoid valve learning. If the brake booster with master cylinder has been replaced, or the brake booster pump or brake master cylinder reservoir has been replaced, linear solenoid valve learning will be automatically performed during the Bleed Brake System procedure. Refer to «BLEEDING - Step 2»(ref-398212-S21353879102011051600000) . Clear the stored linear solenoid valve calibration data. Turn the power switch off. Check that the steering wheel is centered. Check that park (P) is selected. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Select the skid control ECU to clear the linear solenoid valve calibration data using the Techstream. Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Reset Memory. Perform initialization and calibration of the linear solenoid valve. Perform the zero point calibration of the yaw rate and acceleration sensor. Refer to «CALIBRATION»(ref-398097-S11353765862011051600000) . Perform initialization and calibration of the linear solenoid valve. Turn the power switch off. Check that the steering wheel is centered. Check that park (P) is selected. Check that the parking brake is released. NOTE: Linear valve offset learning cannot be started with the parking brake applied. If the parking brake is applied during offset learning, the learning process will be canceled and then restarted when the parking brake is released. Connect the Techstream to the DLC3. Turn the power switch on (IG) with the brake pedal released. NOTE: If the linear solenoid valve offset learning is performed without turning the power switch on (IG), the learning process may not be completed properly because of insufficient auxiliary battery voltage. When the linear solenoid valve offset learning is interrupted, or the learning process is performed with park (P) not selected, DTC C1345 (Linear Solenoid Valve Offset Learning Undone) will be stored. Turn the Techstream on. Switch the skid control ECU to the Test Mode using the Techstream. Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / ECB* Utility / Linear Valve Offset. *: Electronically Controlled Brake System Leave the vehicle stationary without depressing the brake pedal for 1 or 2 minutes. Check that the interval between blinks of the brake warning light / yellow (minor malfunction) changes from 1 second to 0.25 seconds. HINT: The time needed to complete initialization and calibration of the linear solenoid valve varies depending on auxiliary battery voltage. The brake warning light / yellow (minor malfunction) blinks at 1 second intervals during initialization and calibration of the linear solenoid valve and changes to the Test Mode display. The brake warning light / yellow (minor malfunction) blinks at 0.25 seconds intervals if the Test Mode is normal. Check that DTC C1345 (Linear Solenoid Valve Offset Learning Undone) which indicates trouble with stroke sensor zero point learning is not output when the brake warning light / yellow (minor malfunction) changes to the Test Mode display upon initialization and calibration of the linear solenoid valve completion. Enter the normal mode from the Test Mode following the Techstream directions. HINT: Refer to the Techstream operator's service information for further details.
3. PERFORM INITIALIZATION AND CALIBRATION OF LINEAR SOLENOID VALVE (When not Using the Techstream) NOTE: If the brake control has been disabled, or the brake pedal stroke sensor or brake pedal has been replaced, it is necessary to perform linear solenoid valve learning. If the brake booster with master cylinder has been replaced, or the brake booster pump or brake master cylinder reservoir has been replaced, linear solenoid valve learning will be automatically performed during the Bleed Brake System procedure. Refer to «BLEEDING - Step 2»(ref-398212-S21353879102011051600000) . Clear the stored linear solenoid valve calibration data. Turn the power switch off. Check that the steering wheel is centered. Check that park (P) is selected. Check that the parking brake is released. NOTE: Linear valve offset learning cannot be started with the parking brake applied. If the parking brake is applied during offset learning, the learning process will be canceled and then restarted when the parking brake is released. Turn the power switch on (IG) with the brake pedal released. Using SST, connect and disconnect terminals TS and CG of the DLC3 4 times or more within 8 seconds. SST: 09843-18040 TEXT IN ILLUSTRATION *1 Front view of DLC3 Check that no codes other than ABS code 42, VSC code 45 and electronically controlled brake system code 48, 66, or 95 are stored in the diagnostic system. HINT: How to read DTCs: Diagnostic trouble codes are represented by the number of blinks of a warning light. For example, code 21 would be shown by 2 blinks, a pause of 1.5 seconds, and then 1 blink. If one code is detected: The light repeats the same code after a pause of 4 seconds. If multiple codes are detected: The light outputs one code after another with a 2.5-second pause between each code. When all codes have been output, there is a 4-second pause and then the light begins to output the codes again. The ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights do not indicate a normal system code. Remove SST from the terminals of the DLC3. Perform initialization and calibration of the linear solenoid valve. Perform the zero point calibration of the yaw rate and acceleration sensor. Refer to «CALIBRATION»(ref-398097-S11353765862011051600000) . Perform initialization and calibration of the linear solenoid valve. Turn the power switch off. Check that the steering wheel is centered. Check that park (P) is selected. Using SST, connect terminals TS and CG of the DLC3. SST: 09843-18040 TEXT IN ILLUSTRATION *1 Front view of DLC3 Turn the power switch on (IG) with the brake pedal released. NOTE: If the linear solenoid valve offset learning is performed without turning the power switch on (IG), the learning process may not be completed properly because of insufficient auxiliary battery voltage. When the linear solenoid valve offset learning is interrupted, or the learning process is performed with park (P) not selected, DTC 66 (Linear Solenoid Valve Offset Learning Undone) will be stored. Leave the vehicle stationary without depressing the brake pedal for 1 or 2 minutes. Check that the interval between blinks of the brake warning light / yellow (minor malfunction) changes from 1 second to 0.25 seconds. HINT: The time needed to complete initialization and calibration of the linear solenoid valve varies depending on the auxiliary battery voltage. The brake warning light / yellow (minor malfunction) blinks at 1 second intervals during initialization and calibration of the linear solenoid valve and changes to the Test Mode display. The brake warning light / yellow (minor malfunction) blinks at 0.25 seconds intervals if Test Mode is normal. Check that DTC 66 (Linear Solenoid Valve Offset Learning Undone) which indicates trouble with stroke sensor zero point learning is not output when the brake warning light / yellow (minor malfunction) changes to the Test Mode display upon initialization and calibration of the linear solenoid valve completion. Turn the power switch off and disconnect SST from the DLC3.

FREEZE FRAME DATA

1. FREEZE FRAME DATA/INFORMATION Whenever an ABS, VSC or electronically controlled brake system DTC is detected, the skid control ECU stores the current vehicle (sensor) state as Freeze Frame Data. The skid control ECU stores the number of times (maximum: 31) the power switch has been turned from off to on (IG) since the last time the ABS was activated. For DTCs stored in the skid control ECU, information (INF) codes that are contained in the Freeze Frame Data can be displayed on the Techstream. HINT: However, if the vehicle is stopped or at a low speed (7 km/h (4.3 mph) or less), or if a DTC is detected, the skid control ECU will stop counting the number of times the power switch has been turned from off to on (IG). Freeze Frame Data at the time the ABS operates: The skid control ECU stores and updates data whenever the ABS system operates. When the ECU stores data at the time a DTC is detected, the data stored during ABS operation is cleared. Freeze Frame Data at the time a DTC is detected: When the skid control ECU stores data at the time a DTC is detected, no updates will be performed until the data is cleared.
2. CHECK FREEZE FRAME DATA AND INFORMATION Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes. According to the display on the Techstream, select the trouble code data display with Freeze Frame Data. Read the Freeze Frame Data recorded when the DTC was set. Read the information. Select the item that has an information (INF) code from the Freeze Frame Data screen. ABS/VSC/TRAC Tester Display Measurement Item/Range Normal Condition Diagnostic Note Detailed Freeze DTC Detailed code for Freeze Frame DTC / Min.: 0, Max.: 65535 - Number of information (INF) code output is displayed Elapsed Time after Freeze Trigger Elapsed time after freeze trigger / Min.: 0 msec, Max.: 500 msec - - Number of IG ON Number of operations of power switch on (IG) after storing Freeze Frame Data / 0 to 31 - - Elapsed Time Elapsed time after power switch on (IG) / Min.: 0 sec., Max.: 100661.76 sec. - - Buzzer Skid control buzzer / ON or OFF ON: Buzzer on OFF: Buzzer off - Stop Light SW Stop light switch / ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - Parking Brake SW Parking brake switch / ON or OFF ON: Parking brake applied OFF: Parking brake released - Reservoir Warning SW Brake fluid level warning switch / ON or OFF ON: Reservoir level low OFF: Reservoir level normal - Shift Lever Position Shift position information / Fail, 1st-6th/B, D/M, P/N or R Actual shift position - Operated System Operated system status / ABS, VSC, TRAC, BA, PB, PBA, HAB, HA-CTRL, Fail, Non or Sys - ABS: ABS activated VSC: VSC activated TRAC: TRAC activated BA: BA activated PB: PB activated PBA: PBA activated HAB: HAB activated HA-CTRL: Hill-start assist control activated Fail: Fail safe mode activated Non: No system activated Sys: System prohibited Stroke Sensor Brake pedal stroke sensor / Min.: 0 V, Max.: 5 V When brake pedal released: 0.65 to 1.35 V Reading increases when brake pedal is depressed Accumulator Sensor Accumulator pressure sensor / Min.: 0 V, Max.: 5 V Specified value: 2.9 to 4.2 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator Yaw Rate Sensor Yaw rate sensor / Min.: -128°/s, Max.: 127°/s Vehicle stopped: 0°/s Turning right: -128 to 0°/s Turning left: 0 to 127°/s - Lateral G Lateral G / Min.: -25.20 m/s 2 , Max.: 24.91 m/s 2 - During turning: Changes in proportion with acceleration Forward and Rearward G Forward and backward G / Min.: -25.11 m/s 2 , Max.: 24.91 m/s 2 - During acceleration/deceleration: Changes in proportion with acceleration FR Wheel Speed Front speed sensor RH / Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations FL Wheel Speed Front speed sensor LH / Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations RR Wheel Speed Rear speed sensor RH / Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations RL Wheel Speed Rear speed sensor LH / Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations Vehicle Speed Maximum wheel speed sensor / Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations Accelerator Opening Angle % The difference of a present accelerator / Min.: 0%, Max.: 127% When the accelerator pedal released: 0% During accelerator pedal operation: Changes in proportion with the pedal movement ECB* Motor Relay ABS motor relay / ON or OFF ON: Relay on OFF: Relay off - ECB* Main Relay ABS main relay / ON or OFF ON: Relay on OFF: Relay off - IG1 Voltage Value IG1 voltage value / Min.: 0 V, Max.: 20 V - Changes in proportion to auxiliary battery voltage IG2 Voltage Value IG2 voltage value / Min.: 0 V, Max.: 20 V - Changes in proportion to auxiliary battery voltage BS1 Voltage Value BS voltage value / Min.: 0 V, Max.: 20 V - Changes in proportion to auxiliary battery voltage VM1 Voltage Value VM1 voltage value / Min.: 0 V, Max.: 20 V - Changes in proportion to auxiliary battery voltage Motor Relay Voltage Value Motor relay voltage value / Min.: 0 V, Max.: 20 V During motor operation: 12 V No motor operation: 0 V - Steering Angle Sensor Steering angle sensor / Min.: - 3276.8°, Max.: 3276.7° Left turn: Increase Right turn: Decrease - TRAC/VSC Off Mode TRAC/VSC off mode / Normal, TRC OFF or VSC OFF Normal: Normal mode TRC OFF: TRAC off mode VSC OFF: VSC off mode - Regulator Pressure Sensor Regulator pressure sensor / Min.: -1 MPa, Max.: 23.99 MPa - - Regulator Pressure Sensor Output Variant Regulator pressure sensor output variant / Min.: -30 MPa/s, Max.: 225 MPa/s - - Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V When brake pedal released: 0.1 to 0.9 V Reading increases when brake pedal is depressed SLA Solenoid Current Linear solenoid additional valve (SLA) current / Min.: 0 A, Max.: 1.5 A When brake pedal released: 0 A - SLR Solenoid Current Linear solenoid reduction valve (SLR) current / Min.: 0 A, Max.: 1.5 A When brake pedal released: 0 A - Target Oil Pressure Wheel target hydraulic pressure / Min.: 0 MPa, Max.: 20 MPa Changes according to the target wheel cylinder hydraulic pressure - ECB* Solenoid (SSC) Simulator cut solenoid valve (SSC) / ON or OFF ON: Solenoid on OFF: Solenoid off - ECB* Solenoid (SCC) Switching solenoid valve (SCC) / ON or OFF ON: Solenoid on OFF: Solenoid off - ECB* Solenoid (SMC) Master cut solenoid valve (SMC) / ON or OFF ON: Solenoid on OFF: Solenoid off - ECB* Solenoid (SRC) Regulator cut solenoid valve (SRC) / ON or OFF ON: Solenoid on OFF: Solenoid off - *: Electronically Controlled Brake System
3. CLEAR FREEZE FRAME DATA AND INFORMATION NOTE: Clearing the DTCs will also clear the Freeze Frame Data and information (INF) codes. Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Clear the DTCs and Freeze Frame Data. Refer to «DTC CHECK / CLEAR»(ref-398097-S18517405762011051600000) .

FAIL-SAFE CHART

1. FAIL-SAFE FUNCTION OF CONTROL SYSTEM When a malfunction is detected in the brake control system, the skid control ECU turns the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights come on, as well as prohibits ABS, BA, TRAC and VSC operations. If the skid control ECU detects that a system related to the hybrid control system is malfunctioning, it will prohibit operations of the TRAC and VSC systems in order to prevent further malfunctions and to protect the systems. Item Operation Malfunction in the ABS system ABS, BA, TRAC and VSC control prohibited Malfunction in the BA system ABS, BA, TRAC and VSC control prohibited Malfunction in the EBD system ABS, EBD, BA, TRAC and VSC control prohibited Malfunction in the TRAC system ABS, BA, TRAC and VSC control prohibited Malfunction in the VSC system ABS, BA, TRAC and VSC control prohibited
2. FAIL-SAFE FUNCTION OF HYDRAULIC SYSTEM If a malfunction is detected in the brake booster with master cylinder (skid control ECU or brake actuator) or an individual sensor, control will be stopped and brake effort will be generated by the brake booster with master cylinder (hydraulic brake booster). If brake control is stopped due to a malfunction in the hydraulic pressure source, the pressure generated in the master cylinder by the driver is applied to the wheel cylinders to ensure braking force. Item Operation Skid control ECU malfunction Brake booster with master cylinder (hydraulic brake booster) generated braking force Hydraulic pressure controlling components malfunction Brake booster with master cylinder (hydraulic brake booster) generated braking force Power supply components (Hydraulic pressure source) malfunction Braking force solely generated by the driver