CAUTION / NOTICE / HINT NOTICE: When
replacing the skid control ECU (brake actuator assembly), perform
system variant learning and acceleration sensor zero point calibration. Click here
PROCEDURE 1. PRE-INSPECTION (a) Brake pedal inspection (1) Perform a visual inspection and operate the brake pedal to check for any malfunctions. (2) Check the brake pedal height, brake pedal free play and brake pedal reserve distance. Click here HINT: If
the brake pedal height is not within specification, confirm that there
are no other malfunctions before adjusting the brake pedal height. (b) Brake inspection (1) Check that the disc brake pads of each wheel are installed correctly. (2)
Check that the bleeder plug and union bolt is not loose, and that there
are no damaged gaskets or brake fluid leaks, for each wheel cylinder. (c) Brake fluid leaks and air in brake line inspection (1) Check and take a note of the fluid level in the brake master cylinder reservoir assembly. (2) Repeatedly depress the brake pedal and confirm that the brake pedal feels normal (no air in the system, etc.). (3) Check if the brake fluid level in the brake master cylinder reservoir assembly has changed. (4)
If the brake fluid level has decreased, check for leaks due to damaged
brake lines or hoses, loose union nuts, damaged brake master cylinder
sub-assembly seals, etc. (d) Bleeding air from brake system (1) Bleed air from the brake lines and brake actuator assembly. Click here 2. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY) (a) Connect the Techstream to the DLC3. (b) Turn the engine switch on (IG). (c) Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Active Test. Tester Display Measurement Item Control Range Diagnostic Note Motor Relay ABS motor relay Relay OFF/ON Operating sound of motor can be heard Tester Display Motor Relay (d) Fully depress and hold the brake pedal. HINT: Make sure that the brake pedal has travelled excessively before holding it depressed. (e)
Operate the ABS motor relay using the Active Test and check if the
brake pedal height changes when the pump motor is operating. OK: The brake pedal height does not change (the brake pedal travel remains excessive). REPLACE BRAKE ACTUATOR ASSEMBLY 3. CHECK BRAKE MASTER CYLINDER SUB-ASSEMBLY (a) Check that there are no brake fluid leaks and no indications of a malfunction in the brake master cylinder sub-assembly. OK: There are no brake fluid leaks and no indications of a malfunction in the brake master cylinder sub-assembly. REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY 4. INSPECT BRAKE BOOSTER ASSEMBLY (a) Inspect operation of the brake booster assembly. Click here OK: The brake booster assembly is normal. USE SIMULATION METHOD TO CHECK REPLACE BRAKE BOOSTER ASSEMBLY FAIL-SAFE CHART FAIL-SAFE OPERATION The brake actuator assembly turns off the solenoids and
the ECM stops its VSC control according to signals from the skid
control ECU. The vehicle will operate in a manner similar to a vehicle
that is not equipped with ABS, TRAC, secondary collision brake, VSC and
brake hold systems. ABS control will be prohibited,
but EBD control will continue to the extent that EBD control is
possible. If EBD control is impossible, the brake system warning light
(red indicator) will come on to warn the driver. Click here If it is impossible for control to continue, the warning light comes on to inform the driver of system control termination. Click here Item Operation Malfunction in the ABS. ABS, BA, TRAC and VSC control prohibited. Brake hold control prohibited. Malfunction in the BA system. ABS, BA, TRAC and VSC control prohibited. Brake hold control prohibited. Malfunction in the EBD system. ABS, EBD, BA, TRAC and VSC control prohibited. Brake hold control prohibited. Item Operation Malfunction in the engine control system (TRAC and VSC systems). Before control: Disables control. During control: Uses only the brakes to perform control. Malfunction in the brake control system (VSC system). Before control: Disables control. During control: Uses only the engine to perform control. Malfunction in the brake control system (TRAC system). Before control: Disables control. During control: Disables control (by gradually ending control). Item Operation Malfunction in the airbag system (secondary collision brake system). Before control: Disables control. During control: Uses only the brakes to perform control. Malfunction in the engine control system (secondary collision brake system). Before control: Disables control. During control: Uses only the brakes to perform control. FREEZE FRAME DATA FREEZE FRAME DATA (a)
Whenever an ABS DTC is detected, the skid control ECU (brake actuator
assembly) stores the current vehicle (ECU or sensor) state as Freeze
Frame Data. (b) The skid control ECU (brake
actuator assembly) stores the number of times (maximum: 31) the engine
switch has been turned from off to on (IG) since the last time the ABS
was activated. HINT: The skid control ECU (brake actuator assembly) stores and updates data whenever the ABS operates. When the ECU stores data at the time a DTC is detected, the data stored during ABS operation is cleared. When the skid control ECU (brake actuator assembly)
stores data at the time a DTC is detected, no updates will be performed
until the data is cleared. CHECK FREEZE FRAME DATA (a) Turn the engine switch off. (b) Connect the Techstream to the DLC3. (c) Turn the engine switch on (IG). (d) Turn the Techstream on. (e) Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Trouble Codes. (f) Select a DTC to display its Freeze Frame Data. Tester Display Measurement Item Range Normal Condition Diagnostic Note Elapsed Time after Freeze Trigger Elapsed time after freeze trigger Min.: 0 msec, Max.: 510 msec - - Number of IG ON Number of times engine switch turned on (IG) after Freeze Frame Data stored 0 to 31 - - Stop Light SW Stop light switch assembly ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - Parking Brake SW Parking brake switch assembly ON or OFF ON: Parking brake applied OFF: Parking brake released - Gear Position Gear position information P/N, R, 1st-10th, Fail or Not R Actual gear position - Shift Lever Position Shift lever position information P/N, R, D/M, 1st-6th/B or Fail Actual shift lever position - Operated System Operated system status Non, ABS, VSC, TRAC, BA, HAB, Fail, PBA, PB, HA-CTRL, TSC, SCB, Sys Actual operated system Non: No operation is activated. ABS: ABS is activated. VSC: VSC is activated. TRAC: TRAC is activated. BA: BA is activated. HAB: HAB is activated. Fail: Fail-safe mode is activated. PBA: PBA is activated. PB: PB is activated. HA-CTRL: Hill-start assist control is activated. TSC: Trailer sway control activated* SCB: Secondary collision brake is activated. Sys: System prohibit is activated. HINT: *: Not supported Master Cylinder Sensor Master cylinder pressure sensor reading Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.20 to 0.40 V Reading increases when brake pedal is depressed M/C Sensor Grade Master cylinder pressure sensor change Min.: -30 MPa/s, Max.: 225 MPa/s Brake pedal released or pedal held at constant position: 0 MPa/s When brake pedal is being operated: Changes in proportion with the pedal movement speed 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.: -25.10 m/s2, Max.: 24.90 m/s2 - During turning: Changes in proportion with lateral acceleration Forward and Rearward G Forward and backward G Min.: - 25.10 m/s2, Max.: 24.90 m/s2 - During acceleration/deceleration: Changes in proportion with acceleration FR Wheel Speed Front wheel speed sensor RH reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations FL Wheel Speed Front wheel speed sensor LH reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations RR Wheel Speed Rear wheel speed sensor RH reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations RL Wheel Speed Rear wheel speed sensor LH reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations Vehicle Speed Maximum wheel speed sensor reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations Vehicle Speed Grade Vehicle speed grade Min.: -25.10 m/s2, Max.: 24.90 m/s2 Vehicle stopped: 0 m/s2 During driving: Changes in proportion with vehicle acceleration/deceleration Real Engine Torque Actual engine torque Min.: -1024 Nm, Max.: 1023 Nm - - Accelerator Opening Angle % Percentage of accelerator pedal opening angle Min.: 0.0%, Max.: 127.5% The accelerator pedal released: 0.0% During accelerator pedal operation: Changes in proportion with the pedal movement Inspection Mode Inspection mode Other or Inspect Other: Normal mode Inspect: Inspection mode - 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, VSC Expert Mode, VSC OFF Normal: Normal mode TRC OFF: TRAC off mode VSC Expert Mode: VSC expert mode VSC OFF: VSC off mode - Brake Hold Ready Brake hold control permission status OFF or ON ON: Brake hold control permitted OFF: Brake hold control not permitted - Brake Hold Control Mode Brake hold control mode OFF, ON, Release or EPB OFF: Brake hold control is not operating ON: Brake hold control is operating Release: Brake hold control is released EPB: Parking brake is engaged during brake hold control HINT: EPB stands for electric parking brake. CLEAR FREEZE FRAME DATA NOTICE: Clearing the DTCs will also clear the Freeze Frame Data. (a) Turn the engine switch off. (b) Connect the Techstream to the DLC3. (c) Turn the engine switch on (IG). (d) Clear the DTCs and Freeze Frame Data. Click here Excessive Brake Pedal Travel (No Fluid Leaks and No Air in System)
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Chassis > ABS/VSC/TRAC/EPB > Active Test
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Fail-safe Chart
ABS, EBD and BA System 
TRAC and VSC System
Secondary Collision Brake System
Freeze Frame Data
Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Lighting (ext): Hazard Warning Switch
ComponentsCOMPONENTS ILLUSTRATION *1 HAZARD WARNING SWITCH ASSEMBLY (RADIO AND DISPLAY RECEIVER ASSEMBLY) - - InspectionINSPECTION PROCEDURE 1. INSPECT HAZARD WARNING SWITCH ASSEMBLY (RADIO AND DISPLAY RECEIVER ASSEMBLY) *a Component without harness connected (Hazard Warning Switch Assembly (Radio ...
