Wheel Speed Sensor Front Left Front Right Rear left Rear Right Battery + Self Diagnosis Initiate Line ECU Pressure Module Valve Warning Lamp Valve Relay Self Diagnosis ASR Information
Trang 1Anti - Lock Brake System
(Aero Bus)
Trang 2Learning Goals (You Can…)
Understand Characteristics of the Anti-Lock Brake System
State Control Logic
Understand how ABS Components are controlled, operated and checked
State input and output element of the system
Read trouble codes with/without Hi-Scan Pro
Troubleshoot
Repair ABS
Understand System Layout and Location
Trang 4 Stability
Steerability
Shorter emergency brake distance
Drastic reduction of vehicle accidents
Tire protection by avoiding brake flats, thus longer tire service time
Advertising effect, e.g for tourist coaches
Characteristics
Exercise
What is the characteristics of the ABS?
Discuss your opinion in the group and make a note of the most important items
Trang 5ABS General
• Emergency brake 50 km/h (t: 2.5s)
• Asphalt wet
• Front-axle wheel, left
• System configuration IRM (4 ch )
• CV empty, leaf spring suspension
• Emergency brake 50 km/h (t: 2.5s)
• Asphalt wet
• Front-axle wheel, left
• System configuration IRM (4 ch )
• CV empty, leaf spring suspension
V F : vehicle reference speed
V F : vehicle reference speed
V R : braked tire velocity
V R : braked tire velocity
Trang 6A B
How To Calculate Slip Ratio ? ABS General
Exercise
Trang 7ABS General
Maximum Brake Force Utilization
Brake force coefficient µ B as function of brake slip
Trang 8Wheel
Speed
Sensor
Front Left Front Right Rear left Rear Right Battery ( + )
Self Diagnosis Initiate Line
ECU
Pressure Module Valve
Warning Lamp
Valve Relay Self Diagnosis
ASR Information Indicating
ABS General
Exercise : Diagram of Input / Output
Please fill out input and output element on the block diagram
ASR Valve
Trang 9Air Reservoir
Service Brake System
Brake Relay Valve
Brake Cylinder
Check Valve
ABS/ASR
Control
Unit
Pressure Module Valve
Sol V/V
Brake Cylinder
Brake Cylinder
Brake Cylinder
Wheel Speed Sensor
Trang 10Sensor
Trang 11Sensor
Trang 12Sensor
Trang 13Electronic Control Unit
System Layout
Location
Trang 14Wheel Speed Sensor
Bushing
System Layout
Location
Trang 15Pressure Control Valve
Trang 16System Layout Location
Trang 17Components Description
Exercise : ABS Control Module : Service Advices
• Do not expose ABS ECU to splash-water, mud, dust or
mechanical stress such as drop down etc.
• Do not expose ABS ECU to splash-water, mud, dust or mechanical stress such as drop down etc.
• Do not touch the electrical connectors with fingers or
parts other than the wiring harness plugs
• Do not touch the electrical connectors with fingers or
parts other than the wiring harness plugs
• Never weld on a vehicle while ECUs are connected
• Never start the Engine other than the own battery as long
as ECUs are connected
• Never start the Engine other than the own battery as long
as ECUs are connected
• Never run the Engine without a securely connected battery
• Never run the Engine without a securely connected battery
• Never open an ECU nor try to repair it
If you have vehicles with ABS ECU, how you handle it?
Discuss your service points in the group and make a note of the most important items
Trang 18Wheel Speed Sensor
Minimum output voltage : 0.75 V
Components Description
Trang 19connect securely and tight
use grease before assembly avoid strong wire bends
Fix the wires securely in order to prevent chafe marks or other damages
use grease before assembly
do not use force by tools for installing the sensor
Components Description
Exercise : WSS: service advice
When servicing wheel speed sensor , Discuss your service points in the group and make a note at the point
as the shown in the figure
Trang 200.9 ~ 2K Ohm
> 30k Ohm
to chassis ground
> 30k Ohm
to chassis ground
Trang 21Components Description
WSS: service advice
sensor head sensor block
air - gap
In st
al la tio n
e dr um
br ak
e
In st
al la tio n
e dr um
br ak e
The air-gap shall be kept as small
as possible by:
- regular sensor adjusting
- regular bearing adjusting
- by keeping the pulse wheel “run
The sensor block
Trang 22Inlet Port (supply) Outlet Port
(Delivery)
Pressure Control Module
Components Description
Discharge
Trang 24When one side wheel is caught at slippery road or
muddy surface, the slipping wheel idles, that the
vehicle is hard to run power train (differential, axle
shaft) In order to compensate idling for stability,
the ASR, feature controls to brake the idling wheel
properly and transfer the rotating force to the other
wheel to enable launching
Vehicle Speed : 40 km/h or less
Speed Difference between RH and LH Wheels : 25km/h or more
Brake Pedal should not be depressed
Exercise : ASR Valve
Please Describe what is ASR and its function
Trang 25ASR Valve : Service Advice
Components Description
• The single valve (removed from the vehicle) can simply be tested with a multi-meter by a
resistance (Ohm) measurement
• The single valve (removed from the vehicle) can simply be tested with a multi-meter by a
resistance (Ohm) measurement
32~42 Ohm
Trang 27Ex) Wheel Speed Sensor Faults (312, 322)
Fault Codes
Diagnosis
Trang 28Fault Codes
Diagnosis
Code No Probable Cause Repair Instruction
121 System OK
211 CAN: BUS off Correctly connect CAN-Bus and terminating resistor
212 CAN: signal not plausible Check Engine ECU
213 CAN: interruption of communications Correctly connect CAN-Bus and terminating resistor
214 CAN: Time-out Transmission Repair CAN-Bus between ABS/ASR and gearbox
215 CAN: Time-out Engine Repair CAN-Bus between ABS/ASR and Engine ECU
216 CAN: Time-out Engine Brake Check communication line between ABS/ASR and Engine ECU
217 Brake Lamp Switch Check brake lamp switch wiring
228 Wrong EEPROM parameters Load the correct set of parameters
232 Wrong tires on the axles Fit the correct tires and the appropriate pulse rings
242 Under-voltage UB Make correct UB-connection and ground connection
243 Open-circuit UB Make correct UB-connection and ground connection
244 ECU internal error Erase fault code.After resetting, if trouble codes appear again, replace ABS Control
Module
Trang 29Fault Codes
Diagnosis
Code
No Probable Cause Repair Instruction
251 Short-circuit M-FR or M-RL to ground Repair the short circuit
252 Short-circuit M-FR or M-RL to Ubat Repair the short circuit
253 Open-circuit M-FR/RL Make correct ground connection for the valves
254 Reverse polarity M-FR/RL and UB Make correct UB-connection and ground connection
255 Short-circuit M-FL or M-RR or M-ASR to ground Repair the short circuit
256 Short-circuit M-FL or M-FR to Ubat Repair the short circuit
257 Open-circuit M-FL/RR Make correct ground connection for the valves
258 Reverse polarity M-1L/2R and UB Make correct UB-connection and ground connection
312 Open or short-circuit to Ubat, ground, or to other WSS Connect WSS correctly
316 Pulse-ring fault, ABS control of implausible duration Use a faultless pulse ring, check the air gap
411 Air gap, drive-off monitoring, instability, no signal:RL Correct the air gap and the WSS connection
415 Wrong tires : RL Fit the correct tires and the appropriate pulse rings
421 Air gap, drive-off monitoring, instability, no signal : FL Correct the air gap and the WSS connection
425 Wrong tires : FL Fit the correct tires and the appropriate pulse rings
441 Air gap, drive-off monitoring, instability, no signal : RR Correct the air gap and the WSS connection
445 Wrong tires : RR Fit the correct tires and the appropriate pulse rings
461 Air gap, drive-off monitoring, instability, no signal : FR Correct the air gap and the WSS connection
465 Wrong tires : FR Fit the correct tires and the appropriate pulse rings
Trang 30Code
No Probable Cause Repair Instruction
515 FL PCV : Open circuit valve ground
Connect PCV correctly
516 FL PCV : Oven circuit AV
517 FL PCV : Short circuit AV to ground
518 FL PCV : Short-circuit AV* to Ubat
522 RL PCV : Open-circuit EV
523 RL PCV : Short-circuit EV to ground
524 RL PCV : Short-circuit EV* to Ubat
525 RL PCV : Open circuit valve ground
526 RL PCV : Oven circuit AV
527 RL PCV : Short circuit AV to ground
528 RL PCV : Short-circuit AV* to Ubat
532 RR PCV : Open-circuit EV
533 RR PCV : Short-circuit EV to ground
534 RR PCV : Short-circuit EV* to Ubat
535 RR PCV : Open circuit valve ground
536 RR PCV : Oven circuit AV
537 RR PCV : Short circuit AV to ground
538 RR PCV : Short-circuit AV* to Ubat
552 FR PCV : Open-circuit EV
553 FR PCV : Short-circuit EV to ground
Fault Codes
Trang 31Code
No Probable Cause Repair Instruction
554 FR PCV : Short-circuit EV* to Ubat
Connect PCV correctly
555 FR PCV : Open circuit valve ground
556 FR PCV : Oven circuit AV
557 FR PCV : Short circuit AV to ground
558 FR PCV : Short-circuit AV* to Ubat
656 FR PCV : False configuration Connect PCV as per IRM or SL, then configure ECU
712 ASR Solenoid Valve : Open-circuit Connect the ASR solenoid valve correctly
713 ASR Solenoid Valve : Short-circuit to ground Repair the short circuit
714 ASR Solenoid Valve : Short-circuit to Ubat Repair the short circuit
721 ASR Solenoid Valve : External excitation Connect the ASR solenoid valve correctly
726 ASR Solenoid Valve : Configuration If traction control is required, connect ASR sol valve, config ECU
817 Short-circuit DBR to Ubat Correctly connect the DBR
818 Short-circuit DBR to ground or DBR open-circuit Correctly connect the DBR
Fault Codes
Trang 32POWER OFF
With Pushing Self Diagnosis S/W
MAIN & IG S/W ON + Self Diagnosis S/W ON (5sec)
Self Diagnosis S/W OFF
IG,MAIN S/W OFF
Diagnosis
Exercise : Clearing Faults
After fixing the system, you have to clear trouble codes from the ECU.
Discuss your procedure in the group and make a not steps.
Trang 33Exercise : Top 5 Field Problems
Discuss your experience regarding ABS problem in the group and make a note of the most important Top 5 field problems
Trang 34Stop Lamp S/W
11 3
9 12
1 2
2 1
2 1
RR/RH WSS 1 2 3 RR/RH PMV
RR/LH WSS 1 2 3 RR/LH PMV
FRT/RH WSS
3 2 1
FRT/LH PMV
1 2
3 2 1
FRT/RH PMV
2 1
FRT/LH WSS
4 3 2 1
8 7 6 5
9
4 3 2 1
6 5
9
3 2 1
1 2 3
Self Diagnosis Connector 16P
Trang 37E.C.M : Service Advice
Test
Step Test Item Connector Method Value Test Condition
1 ECU Ground 18 pin 10 (+) - Battery (-) < 3Ω Key OFF
2 PMV Ground (F/L,R/R) 18 pin 11 (+) - Battery (-) < 3Ω Key OFF
3 PMV Earth (F/R,R/L) 18 pin 12 (+) - Battery (-) < 3Ω Key OFF
4 ECU Voltage 18 pin 7 (+) - 10 (-) 0 V Key OFF
5 PMV Voltage 18 pin 9 (+) - 10 (-) 0 V Key OFF
6 F/L WSS Resistance 12 pin 5 (+) - 4 (-) 1,570 ~ 1,980 Ω Key OFF
7 F/R WSS Resistance 12 pin 8 (+) - 7 (-) 1,570 ~ 1,980 Ω Key OFF
8 R/L WSS Resistance 12 pin 6 (+) - 5 (-) 1,570 ~ 1,980 Ω Key OFF
9 R/R WSS Resistance 12 pin 9 (+) - 8 (-) 1,570 ~ 1,980 Ω Key OFF
10 F/L WSS 12,18 pin 5 (+) - 10 (-) >30 KΩ Key OFF
11 F/R WSS 12,18 pin 8 (+) - 10 (-) >30 KΩ Key OFF
12 R/L WSS 15,18 pin 6 (+) - 10 (-) >30 KΩ Key OFF
13 R/R WSS 15,18 pin 9 (+) - 10 (-) >30 KΩ Key OFF
14 F/L PMV Resistance 12 pin 2 (+) - 3 (-) 14 ~ 21Ω Key OFF
15 F/R PMV Resistance 12 pin 11 (+) - 12 (-) 14 ~ 21Ω Key OFF
Schematic Diagram (CI-12)
Trang 38
Test
Step Test Item Connector Method Value Test Condition
16 R/L PMV Resistance 15 pin 2 (+) - 3 (-) 14 ~ 21Ω Key OFF
17 R/R PMV Resistance 15 pin 11 (+) - 12 (-) 14 ~ 21Ω Key OFF
18 F/L PMV Resistance 12 pin 1 (+) - 3 (-) 14 ~ 21Ω Key OFF
19 F/R PMV Resistance 12 pin 10 (+) - 12 (-) 14 ~ 21Ω Key OFF
20 R/L PMV Resistance 15 pin 1 (+) - 3 (-) 14 ~ 21Ω Key OFF
21 R/R PMV Resistance 15 pin 10 (+) - 12 (-) 14 ~ 21Ω Key OFF
22 ABS Warning Lamp 18 pin 18 - 10 Lamp “ON”
23 Brake Stop Lamp 9,18 pin 3 - 10 0 V Pedal OFF
21~29 V Pedal OFF
24 DBR Rely 18 pin 16 (+) - 7 (-) 210 ~ 300 Ω Key OFF
25 ASR Lamp 18 pin 17 (+) - 10 (-) Lamp “ON” Key ON
26 Self Diagnosis 18 pin 14 (+) - 10 (-) 2 ~ 4.5 Ω Key ON
> 1 MΩ Key OFF
27 ASR Resistance 15 pin 7 (+) - 4 (-) 42 ~ 52 Ω Key OFF
E.C.M : Service Advice
Schematic Diagram (CI-12)
Trang 39Case Study
Trang 40Case 1.
Case Study
Symptom
ABS warning lamp is ON continuously
Vehicle : Aero Bus Truck Engine : D6A Model Year : 2002 Mileage :
Checked Item
Self diagnosis : 2 5 5 (short PCV Front LH or Rear RH)
Replace wiring harness and PCV