Chrysler 300M Service Manual page 175

5 - 68 BRAKES - ANTILOCK BRAKE SYSTEM
REAR WHEEL SPEED SENSOR
DESCRIPTION
This system uses two-wire wheel speed sensors
known as active wheel speed sensors. One wheel
speed sensor (WSS) and one tone wheel are located
at each front and rear wheel. The rear wheel speed
sensor on rear disc brake applications is mounted to
the rear disc brake adapter (Fig. 5). The rear tone
wheel is an integral part of the rear wheel hub and
bearing.
Fig. 5 Rear Wheel Speed Sensor
1 - PARKING BRAKE CABLE
2 - BACKING PLATE
3 - REAR WHEEL SPEED SENSOR
4 - REAR STRUT
OPERATION
The CAB sends 12 volts to power an Integrated
Circuit (IC) in the sensor. The IC supplies a constant
7 mA power supply to the CAB. The relationship of
the tooth on the tone wheel to the permanent magnet
in the sensor, signals the IC to enable a second 7 mA
power supply. The output of the sensor, sent to the
CAB, is a DC voltage signal with changing voltage
and current levels. The ground for the IC and the
current sense circuit is provided by the CAB.
When a valley of the tone wheel is aligned with the
sensor, the voltage signal is approximately 0.8 volts
and a constant 7 mA current is sent to the CAB. As
the tone wheel rotates, the tooth shifts the magnetic
field and the IC enables a second 7 mA current
source. The CAB senses a voltage signal of approxi-
mately 1.6 volts and 14 mA. The CAB measures the
amperage of the digital signal for each wheel. The
resulting signal is interpreted by the ABS CAB as
the wheel speed.
REMOVAL
NOTE: When removing rear wheel speed sensor
from vehicle, access to the wire harness connector
is through the passenger compartment of the vehi-
cle.
(1) Remove the rear seat cushion, and the rear
seat back, from the interior of the car. Refer to Seats
in the Body section of this manual for the required
procedure to be used for this vehicle.
(2) Disconnect the wheel speed sensor cable from
the wire harness.
(3) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(4) Remove the rear wheel and tire assembly from
the vehicle.
(5) Remove the grommet from the floor pan, along
with the end of the cable that fastens to the wire
harness.
(6) Remove the sensor cable from the routing
bracket attached to the strut tower flange.
(7) Remove the wheel speed sensor head and rout-
ing bracket from the disc brake caliper adapter by
removing the bolt, then the sensor (Fig. 6).
Fig. 6 Wheel Speed Sensor At Adapter
1 - STABILIZER BAR LINK
2 - STABILIZER BAR
3 - LATERAL LINK
4 - BOLT
5 - WHEEL SPEED SENSOR
6 - STRUT ASSEMBLY
7 - NUT
INSTALLATION
(1) Install rear wheel speed sensor and routing
bracket into brake caliper adapter. Install head
attaching bolt (Fig. 6) and tighten to 7 N·m (60 in.
lbs.).
(2) Install the sensor cable to the routing bracket
attached to the strut tower flange.
LH