ABS ACURA CSX 2006 Service Repair Manual

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System Outline
19-108VSA System Components
System Description (cont’d)
CONTROL UNIT
MODULATOR UNIT VSA MODULATOR-
CONTROL UNIT
Brake pressure
signal
 Solenoid control
 Motor control
Communication via F-CAN
VSA
OFF
SWITCH
PARKING
BRAKE
SWITCH BRAKE
FLUID
LEVEL
SWITCH
WHEEL SPEED SENSOR
 Engine torque control request
 Control mode signal
 VSA control enable/disable
 Throttle open angle signal
 Engine revolution signal
 Brake pedal
position switch signal
 Service check signal
 Gear position signal
Wheel rotation
pulse signal
ECM/PCM
BRAKE
PEDAL
POSITION
SWITCH
GAUGE CONTROL MODULE (TACH)
YAW RATE-LATERAL
ACCELERATION
SENSORSTEERING ANGLE
SENSOR
VSAOFFswitchsignal
 Parking brake switch signal
 Brake fluid level switch signal
 Yaw rate signal
 Lateral acceleration signal Steering angle signal
 Indicator drive signal
 Buzzer request signal*
*: ’09 model
This system is composed of the VSA modulator-control unit, the wheel speed sensors, the steering angle sensor, the
yaw rate-lateral acceleration sensor, and the system indicators in the gauge control module (tach). The VSA
modulator-control unit controls the ABS, EBD, TCS, VSA, and brake assist with the brake pressure of each wheel and
reduces engine torque.
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ABS Features
Anti-lock control
Grip force of tire and road surface
Main Control
19-109
COEFFICIENT OF
FRICTIONTARGET SLIP RATE
ROTATIONAL
DIRECTION
RADIAL
DIRECTION
OF THE
ROTATIONAL
DIRECTION
SLIP RATE
LEFT-REAR
WHEEL SPEED
SENSOR RIGHT-REAR
WHEEL SPEED
SENSOR
LEFT-FRONT
WHEEL SPEED
SENSOR RIGHT-FRONT
WHEEL SPEED
SENSOR Select Low
Speed Wheel
Detect
Vehicle Speed
Drive
SolenoidRIGHT-REAR
SOLENOID
LEFT-REAR
SOLENOID
RIGHT-FRONT
SOLENOID
LEFT-FRONT
SOLENOID
CONTROL UNIT
ABS
Control
Reference
Slip Rate
Drive
Solenoid
ABS
Control
Drive
Solenoid
ABS
Control
Drive
Solenoid
ABS
Control
RIGHT-FRONT
LEFT-FRONT
Detect
Wheel Speed
Detect
Slip Rate
RIGHT-REAR
LEFT-REAR Detect
Slip Rate
Detect
Slip Rate
Detect
Slip Rate
Detect
Wheel Speed
Detect
Wheel Speed
Detect
Wheel Speed
Without ABS, when the brake pedal is pressed while driving, the wheels sometimes lock before the vehicle comes to a
stop. In such an event, the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of
the vehicle is reduced if the rear wheels are locked, creating an extremely unstable condition. With ABS, the system
precisely controls the slip rate of the wheels to ensure maximum grip force from the tires, and it thereby ensures
maneuverability and stability of the vehicle. The ABS calculates the slip rate of the wheels based on the four wheel
speeds, and then it controls the brake fluid pressure to reach the target slip rate.
The control unit detects the wheel speed based on the wheel speed sensor signals it receives, then it calculates the
vehicle speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration
based on the wheel speeds.
The control unit calculates the slip rate of each wheel, and transmits the control signal to the modulator unit solenoid
valve when the slip rate is high.
The hydraulic control has three modes: Pressure intensifying, pressure reducing, and pressure retaining.
(cont’d)
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EBD Features
TCS Features
19-110VSA System Components
System Description (cont’d)
REAR WHEEL
BRAKE PRESSURE
With EBD under HEAVY LOAD
at REAR WHEELS
With EBD under LIGHT LOAD
at REAR WHEELS
Without EBD
FRONT WHEEL BRAKE PRESSURE
ANTI-POWER of BRAKE FORCE
TOTAL TRACTION DRIVING POWER
TOTAL TRACTION
BRAKE FORCE
SLIPPERY ROAD SURFACE
NORMAL ROAD SURFACE
The electronic brake distribution (EBD) feature helps control vehicle braking by adjusting the rear brake force in
accordance with the rear wheel load before the ABS operates. Based on the wheel speed sensor signals, the control
unit uses the modulator to control the rear brakes individually. When the rear wheel speed is less than the front wheel
speed, the VSA modulator-control unit retains the current rear brake fluid pressure by closing the inlet valve in the
modulator. As the rear wheel speed increases, and approaches the front wheel speed, the VSA modulator-control unit
increases the rear brake fluid pressure by momentarily opening the inlet valve. This whole process is repeated very
rapidly. While this is happening, kickback may be felt at the brake pedal.
When a drive wheel loses traction on a slippery road surface and starts to spin, the VSA modulator-control unit applies
brake pressure to the spinning wheel, and sends an engine torque control request to the ECM/PCM to slow the
spinning wheel and keep traction.
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Brake Assist Features
19-112VSA System Components
System Description (cont’d)
Pressure
Threshold
Brake Assist
Begins
Time
Threshold Brake Pedal
Effort Reduced
PanicStopwithBrakeAssist
Time
Pressure
Panic Stop without Brake Assist
Normal Stop
Brake assist helps ensure that any driver can achieve the full braking potential of the vehicle by increasing brake
system pressure in a panic situation, bringing the vehicle into a full ABS stop.
If during a panic stop the VSA modulator-control unit determines that the brake system pressure increases above a
threshold in less than a certain amount of time, the VSA modulator-control unit engages brake assist.
Because the brake system pressure crossed the pressure threshold before the time threshold had expired, the VSA
modulator-control unit goes into brake assist mode.
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Modulator Unit
Mode VSA NOValveVSA NC
Valve Inlet
Solenoid Valve Outlet
Solenoid Valve Brake Fluid
Pressure
intensifying
mode
Pressure
retaining
mode
Pressure
reducing
mode
Pressure
adding
mode
19-113
FL RR RL
FR
OUT OUT
IN
IN
VSA NO VSA NC
REGULATOR
VALVE PRESSURE
SENSOR
DAMPING
CHAMBER
RESERVOIR MOTOR
RESERVOIRVSA NC VSA NO
REGULATOR
VALVE IN
IN OUT
OUT
MODULATOR UNIT
IN : INLET SOLENOID VALVE (NORMALLY OPEN)
OUT : OUTLET SOLENOID VALVE (NORMALLY CLOSED)
MASTER CYLINDER
The modulator unit consists of the inlet solenoid valve, the outlet solenoid valve, the VSA NO (normally open)
solenoid valve, the VSA NC (normally closed) solenoid valve, the reservoir, the pump, the pump motor, and the
damping chamber.
The hydraulic control has three modes at ABS action; pressure intensifying, pressure retaining, and pressure reducing.
Pressure adding mode is combined the TCS, VSA, and brake assist action.
The hydraulic circuit is an independent four channel type; one channel for each wheel.




open closed open closed Master cylinder fluid is pumped out to
the caliper.
open closed closed closed Caliper fluid is retained by the inlet and outlet valves.
open closed closed open Caliper fluid flows through the outlet valve to the reservoir.
The motor pumps the reservoir fluid
through the damping chamber to
the master cylinder .
closed open open closed Master cylinder fluid is pumped out by pump with motor through VSA
NC valve to the caliper.
Caliper fluid pressure exceeds
master cylinder pressure.
: The motor will keep running until the operation of the one anti-lock brake control is finished with the first pressure reducing mode.
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19-114VSA System Components
Circuit Diagram
UNDER-DASH
FUSE/RELAY BOX
No. 4 (7.5 A)
IGNITION SWITCH
IG1 HOT in ON (II) and START (III)
BRAKE PEDAL
POSITION SWITCH
Closed: Brake pedal pressed 1
2
WHTRED
YAW RATE-
LATERAL
ACCELERATION
SENSOR
WHT RED 1
3
4
YEL
5
BLK
4
2
1 VSA OFF SWITCH
WHT
WHT
RED
5
No. 3 (40 A)
No.1(100A) No.2(50A)
No. 3 (30 A)
No. 12 (15 A)
UNDER-HOOD FUSE/RELAY BOX
BATTERY
ABS
INDICATOR
BRAKE SYSTEM
INDICATOR
1
VSA ACTIVATION
INDICATOR VSA
INDICATOR
19
28
27
GAUGE CONTROL
MODULE (TACH)
BRNB
WHT
29
RED
GRN
14
RED
G501
C2 C1
E24
F16
YEL
G602
BLU
LT GRN GRYREDBRN
BLK
WHT
LT GRN GRY
H1
D8 36 D2
G502
BLK
WHT
RED
WHT
LT BLU
B
G401
BRAKE FLUID
LEVEL SWITCH
Closed: Low fluid
1 2
BLK
ORN ORN
1
PARKING
BRAKE SWITCH
Closed: Parking
brake applied DATA LINK
CONNECTOR (DLC)
ORN
IG1
6
16
4 714
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µ
µ
DTC 31-xx :
DTC 32-xx :
DTC 33-xx :
DTC 34-xx :
DTC 35-xx :
DTC 36-xx :
DTC 37-xx :
DTC 38-xx :
Subcode Malfunction Note (DTC) YES
NO
19-136VSA System Components
DTC Troubleshooting (cont’d)
ABS Right-front Inlet Solenoid
Valve Malfunction
ABS Right-front Outlet Solenoid
Valve Malfunction
ABS Left-front Inlet Solenoid
Valve Malfunction
ABS Left-front Outlet Solenoid
Valve Malfunction
ABS Right-rear Inlet Solenoid
Valve Malfunction
ABS Right-rear Outlet Solenoid
Valve Malfunction
ABS Left-rear Inlet Solenoid
Valve Malfunction
ABS Left-rear Outlet Solenoid
Valve Malfunction
: Any two-character subcode (see table)
01 Solenoid Initial Pulse 31-01, 32-01, 33-01,
34-01, 35-01, 36-01,
37-01, 38-01
21 Solenoid Pulse 31-21, 32-21, 33-21, 34-21, 35-21, 36-21,
37-21, 38-21
22 Solenoid Speculative 31-22, 32-22, 33-22,
34-22, 35-22, 36-22,
37-22, 38-22
23 Solenoid Stuck ON 31-23, 32-23, 33-23,
34-23, 35-23, 36-23,
37-23, 38-23
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0), then turn it to ON (II) again. 4. Check for DTCs with the HDS.
Replace the VSA modulator-control unit
(see page 19-171).
Intermittent failure, the system is OK at this
time.
Is DT C 31-xx, 32-xx, 33-xx, 34-xx, 35-xx, 36-xx, 37 -x x , or 38-x x i nd i cat ed ?
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µ
µ
µ
µ µ
µ
DTC 41-21:
DTC 42-21:
DTC 43-21:
DTC 44-21:
DTC Appropriate Wheel
YES
NO
YES
NO YES
NO
19-137
Right-front Wheel Lock
Left-front Wheel Lock
Right-rear Wheel Lock
Left-rear Wheel Lock
The DTCs may be indicated under these conditions:
 The vehicle goes into a spin.
 The ABS or VSA continues to operate for a long time.
 Snow, dirt, or debris build-up on the wheel speed sensor or magnetic encoder.
 Misadjusted brake pedal position switch.
 Contaminated brake fluid.
1. Raise the vehicle, and support it with safety stands in the proper locations (see page 1-11).
2. Turn the appropriate wheel by hand.
41-21 Right-front
42-21 Left-front
43-21 Right-rear
44-21 Left-rear
Repair the brake drag.
Go to step 3.
3. Check that the appropriate wheel speed sensor is properly mounted (see page 19-173).
Go to step 4.
Reinstall the wheel speed sensor, and check
the mounting position (see page 19- 173).
4. Turn the ignition switch to ON (II).
5. Clear the DTC with the HDS.
6. Test-drive the vehicle at 10 km/h (7 mph) for 20 seconds or more.
NOTE: Drive the vehicle on a straight section of
road, not on a lift. 7. Check for DTCs with the HDS.
Check for loose terminals in the VSA
modulator-control unit 37P connector. If necessary,
substitute a known-good VSA modulator-control
unit (see page 19-171), and retest.
If any other DTCs are indicated, go to the
indicated DTCs troubleshooting. If DTCs are not
indicated, intermittent failure, the system is OK at
this time.
Is there brake drag?
Is t he w heel speed sensor i nst al l at i on OK ? Is DT C 41-21, 42-21, 43-21, and/ or 44-21
indicated?
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µ
µ
µ
µ µ
µ
µ
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ABS indicator, brake system indicator, and
VSA indicator do not go off
YES
NO
YES
NO YES
NO
YES
NO
19-166
VSA System Components
Symptom Troubleshooting (cont’d)
VSA MODULATOR-CONTROL UNIT 37P CONNECTOR
IG1 (GRY) VSA MODULATOR-CONTROL UNIT 37P CONNECTOR
IG1 (GRY)
1. Turn the ignition switch to LOCK (0).
2. Check the No. 4 (7.5 A) fuse in the under-dash fuse/relay box.
Go to step 3.
Reinstall the checked fuse, then go to step 9.
3. Disconnect the VSA modulator-control unit 37P connector (see step 2 on page 19- 171).
4. Disconnect the yaw rate-lateral acceleration sensor 5P connector (see page 19- 169).
5. Check for continuity between VSA modulator- control unit 37P connector terminal No. 28 and
body ground.
Repair short to body ground in the wire
between the No. 4 (7.5 A) fuse in the under-dash
fuse/relay box and the VSA modulator-control unit
or the yaw rate-lateral acceleration sensor.
Install a new No. 4 (7.5 A) fuse in the under-
dashfuse/relaybox,thengotostep6. 6. Reconnect all connectors.
7. Turn the ignition switch to ON (II).
8. Check the ABS indicator, the brake system
indicator and the VSA indicator for several seconds
when the ignition switch is tuned to ON (II).
Troubleshooting is complete.
Replace the VSA modulator-control unit
(see page 19-171).
9. Disconnect the VSA modulator-control unit 37P connector (see step 2 on page 19-171).
10. Turn the ignition switch to ON (II).
11. Measure the voltage between VSA modulator- control unit 37P connector terminal No. 28 and
body ground.
Go to step 12.
Repair open in the wire between the No. 4
(7.5 A) fuse in the under-dash fuse/relay box and
the VSA modulator-control unit.
12. Turn the ignition switch to LOCK (0).
Wire side of female terminals Wire side of female terminals
Isthefuseblown?
Is there continuity? Does t he i nd i cat or s come on t hen go of f ?
Is there battery voltage?
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Installation
19-172VSA System Components
VSA Modulator-Control Unit Removal and Installation (cont’d)
1. Install the VSA modulator-control unit onto the bracket.
2. Install the bracket with the VSA modulator-control unit to the body.
3. Reconnect the six brake lines, then tighten the flare nuts to the specified torque.
4. Align the connecting surface of the VSA modulator-control unit 37P connector to the VSA modulator-control unit.
5. Pull up the lever of the VSA m
odulator-control unit 37P connector, then confirm the connector is fully seated.
6. Bleed the brake system (see page 19-9).
7. Do the VSA sensor neutral position memorization (see page 19-169).
8. Start the engine, and make sure the ABS and the VSA indicators go off.
9. Test-drive the vehicle, and make sure the ABS, and the VSA indicators do not come on. NOTE: If the brake pedal is spongy, there may be air trapped in the modulator which could then be induced into
the normal brake system during modulation. Bleed the brake system again (see page 19-9).
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