Chrysler 300M 2002 Service Manual page 168

LH
REAR WHEEL SPEED SENSOR (Continued)
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.
(3) Guide the cable through the hole in the floor
pan and install the grommet.
(4) Install wheel and tire assembly on vehicle.
Then torque all wheel mounting stud nuts in proper
sequence until all nuts are torqued to half specifica-
tion. Then repeat tightening sequence to full speci-
fied torque of 129 N·m (95 ft. lbs.).
(5) Lower vehicle to the ground.
(6) Connect the sensor cable to the wiring harness.
(7) Reinstall the rear seat back and seat cushion.
(8) Road test vehicle to ensure proper operation of
the base and ABS systems.
TONE WHEEL
DESCRIPTION
The tone wheel is used in conjunction with the
wheel speed sensors. (Refer to 5 - BRAKES - ABS/
ELECTRICAL/FRONT WHEEL SPEED SENSOR -
DESCRIPTION) or (Refer to 5 - BRAKES - ABS/
ELECTRICAL/REAR WHEEL SPEED SENSOR -
DESCRIPTION)
OPERATION
The tone wheel is used in conjunction with the
wheel speed sensors. (Refer to 5 - BRAKES - ABS/
ELECTRICAL/FRONT WHEEL SPEED SENSOR -
OPERATION) or (Refer to 5 - BRAKES - ABS/ELEC-
TRICAL/REAR WHEEL SPEED SENSOR - OPERA-
TION)
INSPECTION
Tone wheels can cause erratic wheel speed sensor
signals. Inspect tone wheels for the following possible
causes.
• missing, chipped, or broken teeth
• contact with the wheel speed sensor
• wheel speed sensor to tone wheel alignment
• wheel speed sensor to tone wheel clearance
• excessive tone wheel runout
• tone wheel loose on its mounting surface
If a front tone wheel is found to need replacement,
the drive shaft must be replaced. No attempt should
be made to replace just the tone wheel. Refer to DIF-
FERENTIAL AND DRIVELINE for removal and
installation.
If a rear tone wheel is found to need replacement,
the rear hub and bearing must be replaced. No
attempt should be made to replace just the tone
wheel. Refer to SUSPENSION for removal and
installation.
BRAKES - ANTILOCK BRAKE SYSTEM 5 - 69
If wheel speed sensor to tone wheel contact is evi-
dent, determine the cause and correct it before
replacing the wheel speed sensor or tone wheel.
Check the gap between the speed sensor head and
the tone wheel to ensure it is within specifications.
Refer to SPECIFICATIONS in this section.
Excessive wheel speed sensor runout can cause
erratic wheel speed sensor signals. Refer to SPECI-
FICATIONS in this section for the maximum allowed
tone wheel runout. If tone wheel runout is excessive,
determine if it is caused by a defect in the driveshaft
assembly or hub and bearing. Replace as necessary.
Tone wheels are pressed onto their mounting sur-
faces and should not rotate independently from the
mounting surface. Replacement of the front drive-
shaft or rear hub and bearing is necessary.
TRACTION CONTROL SWITCH
REMOVAL
The traction control switch in located in the upper
right trim bezel on the instrument panel. The upper
right trim bezel must be removed to service the
switch. Refer to Upper Right Trim Bezel Removal
and Installation.
(1) With the bezel removed, press the tabs in at
both sides of the switch and remove the switch from
the bezel.
INSTALLATION
(1) Position the switch over the hole in the upper
right bezel, push through hole and firmly snap into
place.
(2) Install the upper right trim bezel. Refer to
Body, Instrument Panel, Upper Right Trim Bezel,
Installation.
HYDRAULIC/MECHANICAL
OPERATION - HYDRAULIC CIRCUITS AND
VALVES
The hydraulic fluid control valves within the HCU
control the flow of pressurized brake fluid to the
wheel brakes during the different modes of ABS
braking. The following paragraphs explain how this
works. For purposes of explanation only, it is
assumed that only the right front wheel is experienc-
ing antilock braking; the following diagrams show
only the right front wheel in an antilock braking
operation.