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44-0
ANTI-LOCK BRAKE SYSTEM (ABS)
BRAKE
Fuse 51
10A
HOT IN
RUN
FUSE
BLOCK-
REAR
Connector
C1
F8
B5
C3
C11
C2
See Ground
Distribution,
page 14-2.
C3
F1
C1
F3
BLK
0.5
BLK
0.8
G107
(4.2L)
(5.3L)
GRY
0.35
B6
Data lines
Class 2
serial
data
LT BLU
0.35
Class 2
serial data
B1
INSTRUMENT
PANEL
CLUSTER
(IPC)
Connector
C2
Anti-
Lock
IGN E
Fuse 22
10A
HOT IN
RUN
AND START
FUSE
BLOCK-
UNDER-
HOOD
Connector
C2
B6
PNK
0.35
STOP
LAMP
SWITCH
Connector
D
A
B
BRAKE
FLUID
LEVEL
SWITCH
Connector
ABS
Fuse 33
60A
HOT AT ALL TIMES
C7
B
RED
5
BRN
0.35
BRN
0.35
B8
C2
FUSE
BLOCK-
UNDERHOOD
Connector
B10
C2
C
B5
ELECTRONIC
BRAKE
CONTROL
MODULE
(EBCM)
Connector
PPL
0.5
Brake fluid level
sensor signal
PPL
0.35
C3
E3
PPL
0.35
A1
B
C1
Ignition 3
voltage
TCC brake switch/
cruise control
release signal
M
12V
Brake
A
C1
BLK
5
G304
Pump
GND
PPL
0.35
Automatic
Transmission
Controls
FRONT
AXLE
ACTUATOR
Connector
B
BLK
0.5
FUSE
BLOCK-
UNDERHOOD
Connector
See
Indicators
TCC
See Power
Distribution,
Page 10-13.
See Power
Distribution,
page 10-13.
PNK
0.35
Circuit Schematic
44-1
ANTI-LOCK BRAKE SYSTEM (ABS)
LT GRN/
BLK
0.35
PPL/WHT
0.35
YEL/BLK
0.35
TAN
0.35
DK GRN
0.35
LT BLU
0.35
YEL
0.35
B1
ELECTRONIC
BRAKE
CONTROL
MODULE
(EBCM)
Connector
POWER-
TRAIN
CONTROL
MODULE
(PCM)
(4.2L)
(5.3L)
Connector 4.2L
Connector 5.3L
C1*
25
Vehicle
speed
signal
C2
*10
*2
VSS low
signal
Vehicle
speed
signal
WHEEL
SPEED
SENSOR
(WSS)
RF
Connector
B
A
RF wheel
speed
sensor
low
reference
B3
RF wheel
speed
sensor
signal
A3
WHEEL
SPEED
SENSOR
(WSS)
LF
Connector
B
A
LF wheel
speed
sensor
low
reference
A2
LF wheel
speed
sensor
signal
B2
Twisted
Twisted
C2
C101
Connector
C2
YEL/BLK
0.35
**20
**21
C2**
49
*
4.2L
**
5.3L
VSS high
signal
Automatic
Transmission
Controls
C107
Connector
B11
YEL/BLK
0.35
5.3L
Circuit Schematic
44-2
ANTI-LOCK BRAKE SYSTEM (ABS):
TRACTION CONTROL SYSTEM
(TCS)
TAN/BLK
0.35
ORN/BLK
0.35
PPL/WHT
0.35
IGN E
Fuse 22
10A
HOT IN
RUN
FUSE
BLOCK-
UNDER-
HOOD
Connector
C2
B6
PNK
0.35
B7
FUSE
BLOCK-
UNDERHOOD
Connector
B10
C1
ELECTRONIC
BRAKE
CONTROL
MODULE
(EBCM)
Connector
Traction
control
active
telltale
C3
F2
B4
A4
Requested
torque
signal
Delivered
torque
signal
A8
HVAC 1
Fuse 39
10A
HOT IN
RUN
FUSE
BLOCK-
REAR
Connector
C1
F5
C11
D5
POWER-
TRAIN
CONTROL
MODULE
(PCM)
(4.2L)
(5.3L)
Connector 4.2L
Connector 5.3L
C2*
12
C2*
11
Delivered
torque
signal
Requested
Torque
signal
7
TRACTION
CONTROL
SWITCH
(2WD)
Connector
1
5
4
TRAC
OFF
Indicator
Low
TRAC
indicator
2
6
Traction
control
switch
signal
A6
C2
Service
traction
control
signal
Traction
disable
switch
Dash and
Console
Lights
BRN/
WHT
0.35
BRN/WHT
0.35
LT BLU
0.35
WHT
0.35
BRN/WHT
0.35
LT BLU
0.35
WHT
0.35
C101
Connector
D3
D2
C101
Connector
A6
TAN/BLK
0.35
ORN/BLK
0.35
BLK
0.35
SP201
C
G201
See Ground
Distribution,
page 14-5.
See Ground
Distribution,
page 14-5.
BLK
0.5
Air Conditioning:
Automatic
Air Conditioning:
Manual
PNK
0.35
BRN
0.35
See Power
Distribution,
page 10-13.
PNK
0.35
C2**
5
C1**
13
*
4.2L
**
5.3L
See Power
Distribution,
page 10-13.
See Power
Distribution,
page 10-13.
Dash and
Console
Lights
Illumination
3
BRN OR
PNK
0.35
Circuit Schematic
44-3
ANTI°LOCK BRAKE SYSTEM (ABS)
120°3
This vehicle is equipped with one of the following
antilock braking systems.
S
EBC325
S
EBC325S (w/NW7)
The vehicle is equipped with the following braking
enhancement systems.
S
Antilock Brake System (ABS)
S
Dynamic Rear Proportioning (DRP)
S
Traction Control System (TCS) (w/NW7)
The following components are involved in the operation
of the above systems.
S
Electronic brake control module (EBCM) -The
EBCM controls the system functions and detects
failures. The EBCM contains the following
components.
S
System relay -The system relay is internal to
the EBCM. The system relay is energized when
the ignition is ON. The system relay supplies
battery positive voltage to the solenoid valves
and to the pump motor. This voltage is referred
to as system voltage.
S
Solenoids -The solenoids are commanded ON
and OFF by the EBCM to operate the
appropriate valves in the brake pressure
modulator valve (BPMV).
S
Brake pressure modulator valve (BPMV) -The
BPMV uses a 3-circuit configuration to control the
left front wheel, the right front wheel, and the
combined rear wheels. The BPMV directs fluid to
the left front and right front wheels independently.
The BPMV directs fluid to the two rear wheels on a
single hydraulic circuit. The BPMV contains the
following components.
S
Pump motor
S
Three isolation valves
S
Three dump valves
S
A front low-pressure accumulator
S
A rear low-pressure accumulator
S
Wheel speed sensors (WSS) -As the front wheels
spin, toothed rings located at each wheel hub
interrupt magnetic fields in the wheel speed
sensors. This causes each wheel speed sensor to
generate an AC signal. The EBCM uses these AC
signals to calculate the wheel speed. The wheel
speed sensors are serviceable only as part of the
wheel hub and bearing assemblies. Any
imperfections in the toothed ring, such as a missing
or damaged tooth, can cause an inaccurate WSS
signal.
S
Vehicle speed sensor (VSS) -The input signal for
rear wheel speed originates at the VSS. The
powertrain control module (PCM) receives rear
wheel speed input from the VSS and supplies this
information to the EBCM.
S
Traction control switch (w/NW7) -The TCS is
manually disabled or enabled using the traction
control switch. The TCS can be programmed to be
automatically enabled or disabled when the ignition
is turned ON. The factory default is for the TCS to be
automatically enabled. Refer to Programming the
Traction Control Automatic Engagement Feature.
Initialization Sequence
The EBCM performs one initialization test each ignition
cycle. The initialization of the EBCM occurs when the
following conditions are met:
S
The ignition is ON.
S
The bulb check has been completed.
S
Vehicle speed is greater than 6 km/h (4 mph).
The initialization sequence briefly cycles each solenoid
and the pump motor to verify proper operation of the
components. The EBCM sets one or more DTCs in
accordance with any malfunction that is detected.
The EBCM defines a drive cycle as the completion of
the initialization sequence.
Circuit Operation
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