1. Pre-collision Safety System-W
Overall
This system will operate the respective crash dampening components in order to help reduce the damage caused by the unavoidable collision
Seat Belt Retraction
[System Name]
-A: Pre-collision Safety System
-W: Pre-crash Safety system
This system is equipped for –A and –W models as OPT
For frontal collision only (not operate at side and back collision)
Brake Assist Standby

2. Pre-collision Safety System-W
System Diagram
Serial Communication
Millimeter Wave Radar Sensor
Distance Control ECU
Steering Angle Sensor
Brake Actuator
Yaw Rate Sensor
Deceleration Sensor
Master Cylinder Pressure Sensor
Skid Control ECU
CAN
Front Seat Outer Belts (D & P)
Seat Belt Motors
DLC3
Master Cylinder Cut Solenoid Valves
Vehicle Speed Sensors
Pump Motor
Seat Belt Control ECU
Stop Light Switch
Driver Side J/B ECU
Gateway ECU
Front Seat Inner Belts (D & P)
Seat Belt Buckle Switches
BEAN
Combination Meter
Master Warning Light
Multi-information Display
Airbag Sensor Assembly

3. Pre-collision Safety System-W
Layout of Main Components
Seat Belt Control ECU
Front Seat Outer Belts (D & P)
Seat Belt Motors
Skid Control ECU
(3UZ-FE Engine)
Front Seat Inner Belts (D & P)
Seat Belt Buckle Switches
Millimeter Wave Radar Sensor
Brake Actuator (3GR-FSE Engine)
Skid Control ECU
Master Cylinder Pressure Sensor
Master Cylinder Cut Solenoid Valves
Pump Motor

4. Pre-collision Safety System-W
Layout of Main Components
Steering Angle Sensor
Yaw Rate & Deceleration Sensor
Gateway ECU
Distance Control ECU
Driver Side J/B ECU
Buzzer
Airbag Sensor Assembly

5. Pre-collision Safety System-W
General Operation
There are two operations
[Pre-collision Operation]
[Sudden Braking Operation]
Unavoidable Collision Condition
Brake pedal is depressed suddenly
Seat Belt
Brake Assist
Pre-collision Operation (unavoidable collision)
The driver and front passenger seat belts are retracted
The brake assist will be rendered in the standby mode and operated at the instant the brake pedal is pressed
Sudden Braking Operation
Standby Mode
Retraction

6. Pre-collision Safety System-W
General Operation
Two operations are operated under the conditions shown below 70 60
Pre-collision Operation
Seat Belt Retraction
Brake Assist Standby 50
Sudden Braking Operation
Seat Belt Retraction
Vehicle Speed (km/h) 40
Sudden Braking Operation
Seat Belt Retraction 30
[Operating Conditions for Pre-collision Safety System]
NOTE: Except during system failure
Pre-collision operation (seat belt retraction only)
Seat belt is fastened
Relative vehicle speed approx mph (30 km/h) or more
Sudden braking operation (seat belt retraction)
Vehicle speed approx. 8.8 mph (14 km/h) or more
Pre-collision operation (seat belt retraction and brake assist standby) 20 10
Pre-collision Operation
Seat Belt Retraction 10 20 30 40 50 60
Relative Speed (km/h)

7. Pre-collision Safety System-W
General Operation
Operation conditions (detail)
Operation
Pre-collision Operation
Sudden Braking Operation
Seat Belt Retraction
Brake Assist Standby
Vehicle Condition
Unavoidable Collision (Millimeter wave radar sensor detects collision objects)
Sudden Braking (Skid control ECU determines the sudden braking condition)
Vehicle Speed
0 mph (0 km/h)
Approx. 8.8 mph (14 km/h) or more
Relative Speed
Approx mph (30 km/h) or more 
Brake Pedal
Depressed
Seat Belt
Fastened
Other Condition
IG-ON
No system malfunction

8. Pre-collision Safety System-W
Pre-crash Operation
Distance Control ECU determines that an unavoidable collision condition exists based on the sensor signals
Millimeter Wave Radar Sensor
Speed Sensor
Distance Control ECU
Steering Angle Sensor
Yaw Rate & Deceleration Sensor
Detects unavoidable collision
Operation Request
Skid Control ECU
Switches the brake assist in standby mode
Seat Belt Control ECU
Brake pedal is depressed
Retracts the seat belt
Seat belt operation: Only the fastened seat belt side operates
Brake assist is operated at the instant
Brake Actuator
Seat Belt Motors

9. Pre-collision Safety System-W
Sudden Braking Operation
Skid Control ECU determines the sudden braking condition based on the sensor signals
Speed Sensor
Stop Light Switch
Master Cylinder Pressure Sensor
Skid Control ECU
Detects sudden braking
Operates brake assist
Operation Request
Brake Actuator
Seat Belt Control ECU
Only the fastened seat belt side operates
Retracts the seat belt
Seat Belt Motors

10. Pre-collision Safety System-W
Millimeter Wave Radar Sensor
This sensor detects the distance, relative speed, and the direction of the object by reflection millimeter wave
The millimeter wave radar sensor also functions as radar sensor for the dynamic radar cruise control system
Detection Item
Detection Method
Distance
The length of time (Emit  Reflection  Receive)
Azimuth
The angle of reflected waves
Relative Speed
The change of the frequencies between emit and received wave (Utilization of Doppler Effect)

11. Reference (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Doppler effect
Frequency F
Frequency F’
(Becomes higher frequency)
Own Vehicle Hz +
Change of Frequency (Between emit and received wave) - - + km
Relative Speed

12. Pre-collision Safety System-W
Millimeter Wave Radar Sensor
The sensor circuit consists of 1 transmission antenna and 9 reception antennas
Transmission Antenna
Signal Processing Circuit
76 GHz
Approx. 4 °C
Approx. 20 °C
Above 150m
Reception Antenna
Image Diagram

13. Pre-collision Safety System-W
Front Seat Outer Belt
Seat belt motor is added to retract the seat belt
Retractor
Electric Tension Reducer Solenoid
Pretensioner
Seat Belt Motor

14. Pre-collision Safety System
Confidential -A -W
Front Seat Outer Belt
Construction and retraction operation of seat belt motor
Seat Belt
Clutch Mechanism
Retractor Shaft
Reduction Gears
Retraction Direction
Seat Belt Motor

15. Pre-collision Safety System
Confidential -A -W
Front Seat Outer Belt
Clutch mechanism
Seat Belt Retraction
Clutch mechanism is locked by seat belt motor operation
Clutch Free
Clutch Lock
Normal Operation
(Seat Belt is Free)
Pre-crash Operation
(Seat Belt Retraction)

16. Pre-collision Safety System-W
Combination Meter
Two types of warning messages are used for this system
Warning Message
Condition
DTC
System malfunction ON 
Dirty millimeter wave sensor
Poor conditions for millimeter wave radar sensor
Overheated seat belt control ECU 
Warning message request signal is output from seat belt control ECU
The Pre-collision Safety System is inoperative when these messages appear on multi-information display
PSC
DISABLED NOW
CHECK PCS

17. Pre-collision Safety System-W
Diagnosis
DTCs are stored in Seat Belt Control ECU
DTCs
Detection Item
B2000
Right side motor line malfunction Hi
B2021
Left side lower MOS malfunction Open
B2001
Right side motor line malfunction Lo
B2025
Right side current detection circuit malfunction Hi
B2002
Right side motor line malfunction Open
B2026
Right side current detection circuit malfunction Lo
B2005
Left side motor line malfunction Hi
B2027
Right side over-current malfunction
B2006
Left side motor line malfunction Lo
B2030
Left side current detection circuit malfunction Hi
B2007
Left side motor line malfunction Open
B2031
Left side current detection circuit malfunction Lo
B2015
Right side upper MOS malfunction Open
B2032
Left side over-current malfunction
B2016
Right side lower MOS malfunction Open
B2035
Power supply relay adherence malfunction
B2020
Left side upper MOS malfunction Open
B2036
Power supply relay malfunction Open
The diagnosis circuit of this system is integrated in the seat belt control ECU

18. Pre-collision Safety System-W
Diagnosis
DTCs are stored in Seat Belt Control ECU
DTCs
Detection Item
B2040
EEPROM malfunction
B2064
Vehicle type signal malfunction
B2041
Fall of the Raised voltage
B2065
Malfunction of Pre-crash safety ECU
B2043
Fall of the +B voltage
U0100
Lost Communication With ECM/PCM "A"
B2047
ECU inner circuit malfunction
U0122
Lost Communication With Vehicle Dynamics Control Module
B2055
Radar sensor malfunction
U0145
Lost Communication With Body Control Module "E"
B2056
Axial gap of the radar sensor
U0235
Lost Communication With Cruise Control Front Distance Range Sensor
B2059
Vehicle speed malfunction of Pre-crash safety ECU
U1101
Lost Communication With Distance Control ECU
B2060
ABS malfunction
U1102
Lost Communication With Laser Sensor
B2063
Buckle switch malfunction
The diagnosis circuit of this system is integrated in the seat belt control ECU

19. Pre-collision Safety System-W
Millimeter Wave Radar Sensor
After the replacement or reinstall of this sensor, adjust the sensor angle
Adjustment procedure is the same as the LS430
Replacement
Reinstall
Adjustment

20. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
5 vehicle conditions
3, Standard Tire Pressure
4, Luggage is unloaded
2, Level Ground
1, No large metal pieces
Approx. 14 m (45.93 ft)
5, Standard Vehicle Height
Approx. 10 m (32.81 ft)

21. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Adjustment in vertical direction
Specified Level
1. Remove dust and oil on the level rack, and set the specified level on the center
2. Using a hexagon wrench, turn and adjust screw A to level the millimeter wave radar sensor
Screw A
Approx. 0.67° per turn
1. Set the specified level
2. Turn screw A to level the millimeter wave radar sensor

22. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Set SST (reflector)
SST:
( , )
Reflector placement point
5 m (16.41 in.)
3. Adjust the reflector height to the same height as the millimeter wave radar sensor
4. Place the reflector
12 mm
(0.47 in.)
3. Adjust the reflector height
4. Place the reflector

23. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Confirm current distance by tester
CRUISE
5. Turn the ignition switch to the ON position, and push the cruise control main switch ON–OFF button on
6. Connect the Hand-held tester or Intelligent Tester-II to DLC3
5. IG ON and cruise main switch ON
6. Connect Hand-held Tester or Intelligent Tester-II

24. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Confirm current distance by tester
5.0
0.7
7. Transfer the “Beam Axis Adjustment”
8. Confirm that the current distance (reference value) is approximately 5 m (16.41 ft)
7. Transfer the ”Beam Axis Adjustment”
8. Confirm that the “Distance” is approx. 5 m (16.41 ft)

25. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Adjust in horizontal direction
5.0
0.0
Screw B
Approx. 0.21° per turn
9. Adjust the horizontal direction, turn and adjust screw B until the divergence on the screen becomes 0.0 ° (Both right and left)
9. Turn screw B until the “Right / Left Side” becomes 0.0 °

26. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Reset the driving learning values
Metal (such as aluminum foil)
10. Cover the sensor’s right half with metal (such as aluminum foil) for approx. 10 sec. (When the reset is completed, the buzzer sounds for 10 sec.)
Notice: Be sure to keep the reflector in place and that there is nothing between the sensor’s left half and the reflector
11, Disconnect the Hand-held Tester or Intelligent Tester-II from DLC3
10. Reset the driving learning values
(cover the sensor approx. 10 sec.)
11. Disconnect the Hand-held Tester or Intelligent Tester-II

27. Service Point (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
Adjustment
Recheck vertical adjustment
Specified Level
Screw A
12. Remove dust and oil on the level rack, and set the specified level on the center
13. Using a hexagon wrench, turn and adjust screw A to level the millimeter wave radar sensor
Finish
Approx. 0.67° per turn
12. Set the specified level
13. Turn screw A to level the millimeter wave radar sensor

28. Pre-collision Safety System-W
Precaution for Pre-collision Safety System Operation
Cases that the system operates even if there is no danger of collision
Cases that the system operates even if there is no danger of collision
-Object on road surface at corner entrance (Guard Rail, Street Light, Sign, Signboard)
-Opposing traffic vehicle during cornering
-Opposing traffic vehicle at intersection
-Narrow Iron Bridge
-Metal object, steel plate, or bump on road surface
These are not abnormal

29. Pre-collision Safety System-W
Precaution for Pre-collision Safety System Operation
The millimeter wave radar sensor might not be able to detect the following objects as collision objects
Objects that cannot be detected
Plastic items
(Safety Cones, etc.), etc.
Objects that cannot be detected in a stable manner
People, Bicycles, Motorcycles, Trees, Animals, Snow Fence, etc.

31. Reference (Pre-collision Safety System)-W
Millimeter Wave Radar Sensor
What is a millimeter wave ?
Millimeter Wave mm
(0.04 – 0.40 in.)
(In a vacuum)
200 kHz
2 MHz
25 MHz
300 MHz
2 GHz
30 GHz
300 GHz
Long Wave
Short Wave
Micro Wave
Millimeter Wave
The millimeter wave radar is less affected by weather conditions such as rain, fog, or snow, and provides excellent characteristic for recognizing objects AM
(1 MHz) FM
(80 MHz)
Cellular Mobile Phone
(800 MHz)
Millimeter Wave Radar Sensor
(76 GHz)