2002 CHRYSLER CARAVAN run flat

CONDITION POSSIBLE CAUSES CORRECTION
3. Incorrect front wheel camber 3. Check and reset front wheel camber
4. Power steering gear imbalance 4. Replace power steering gear
5. Wheel braking 5. Correct braking condition causing lateral
pull
Excessive Steering Free
Play1. Incorrect Steering Gear Adjustment 1. Adjust Or Replace Steering Gear
2. Worn or loose tie rod ends 2. Replace or tighten tie rod ends
3. Loose steering gear mounting bolts 3. Tighten steering gear bolts to specified
torque
4. Loose or worn steering shaft
coupler4. Replace steering shaft coupler
Excessive Steering Effort 1. Low tire pressure 1. Inflate all tires to recommended
pressure
2. Lack of lubricant in steering gear 2. Replace steering gear
3. Low power steering fluid level 3. Fill power steering fluid reservoir to
correct level
4. Loose power steering pump drive
belt4. Correctly adjust power steering pump
drive belt
5. Lack of lubricant in ball joints 5. Lubricate or replace ball joints
6. Steering gear malfunction 6. Replace steering gear
7. Lack of lubricant in steering coupler 7. Replace steering coupler
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL ALIGNMENT
PRE-WHEEL ALIGNMENT INSPECTION
Before any attempt is made to change or correct
the wheel alignment, the following inspection and
necessary corrections must be made to ensure proper
alignment.
(1) Verify that the fuel tank is full of fuel. If the
tank is not full, the reduction in weight will affect
the curb height of the vehicle and the alignment
angles.
(2) The passenger and luggage compartments of
the vehicle should be free of any load that is not fac-
tory equipment.
(3) Check the tires on the vehicle. All tires must be
the same size and in good condition with approxi-
mately the same amount of tread wear. Inflate all
the tires to the recommended air pressure.
(4) Check the front wheel and tire assemblies for
excessive radial runout.
(5) Inspect lower ball joints and all steering link-
age for looseness, binding, wear or damage. Repair as
necessary.(6) Check suspension fasteners for proper torque
and retighten as necessary.
(7) Inspect all suspension component rubber bush-
ings for signs of wear or deterioration. Replace any
faulty bushings or components before aligning the
vehicle.
(8) Check the vehicle's curb height to verify it is
within specifications. Refer to Curb Height Measure-
ment.
WHEEL ALIGNMENT SETUP
(1) Position the vehicle on an alignment rack.
(2) Install all required alignment equipment on
the vehicle per the alignment equipment manufactur-
er's instructions. On this vehicle, a four-wheel align-
ment is recommended.
NOTE: Prior to reading the vehicle's alignment
readouts, the front and rear of vehicle should be
jounced. Induce jounce (rear first, then front) by
grasping the center of the bumper and jouncing
each end of vehicle an equal number of times. The
bumper should always be released when vehicle is
at the bottom of the jounce cycle.
(3) Read the vehicle's current front and rear align-
ment settings. Compare the vehicle's current align-
RSWHEEL ALIGNMENT2-51
WHEEL ALIGNMENT (Continued)
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OPERATION
In order to achieve all-wheel drive operation in
reverse, the overrunning clutch locking functional direc-
tion must be reversible. The bi-directional overrunning
clutch (BOC) changes the operational mode direction
depending on the propeller shaft direction. The propel-
ler shaft rotates in the clockwise (when viewed from the
front) direction when the vehicle is moving forward,
which indexes the BOC to the forward overrunning
position. When the vehicle is in reverse, the propeller
shaft will rotate counter-clockwise and index the BOC
to the reverse overrunning position.
The BOC acts as a mechanical stator. It is active
(transmitting torque), or it is not active and in over-
running mode (not transmitting torque). This ªall or
nothingº approach to torque transfer would cause a
sudden application of all available power to the rear
wheels, which is not desirable. Therefore it is run in
series with a viscous coupler to smooth, dampen, and
limit the transmission of torque to the rear axle and
to prevent a step style torque input to the rear axle.
STEADY STATE, LOW TO MODERATE SPEED, NO
FRONT WHEEL SLIP, FORWARD DIRECTION
During normal driving conditions, (no wheel slip), the
inner shaft (front axle) and outer race (viscous coupler)
are running at different speeds due to the different gear
ratios between the front and rear differentials. In this
condition, the outer race is always spinning faster (over-
driving between 5-32 rpm) than the inner shaft. When
the BOC (Fig. 29) is running under these conditions, at
low vehicle speeds the drag shoes and the cage keep the
rollers up on the left side (forward side) of the inner
shaft flats. This is what is known as ªoverrunning
mode.º Notice that when the clutch is in overrunning
mode, the rollers are spinning clockwise and with the
outer race, thus no torque is being transferred.
NOTE: Low speed, forward and reverse operation is
identical, just in opposite directions. (Fig. 29) shows
forward direction in reverse the rollers are on the other
side of the flats due to a reversal of the cage force.
TRANSIENT CONDITION (BOC LOCKED), FRONT
WHEEL SLIP, FORWARD DIRECTION
When the front wheels lose traction and begin to
slip, the propeller shaft and rear axle pinion speed
difference decreases to zero. At this point the input
shaft (cam) becomes the driving member of the BOC
(Fig. 30), compressing the rollers against the outer
race. This locks the input shaft with the outer race
and transmits torque to the housing of the viscous
coupler, that in turn transmits torque to the rear
axle pinion. It should also be noted that when the
device is locked, the inner shaft and the outer raceare rotating at the same speed. The rollers are
pinched at this point and will stay locked until a
torque reversal (no front wheel slip) occurs. When
locked, the viscous coupler slips during the torque
transfer and the amount of torque transferred is
dependent on the coupling characteristic and the
amount of front wheel slip.
Fig. 29 BOC Operation at Low Speeds With No
Front Wheel Slip
1 - CAGE
2 - ROLLER
3 - INPUT SHAFT
Fig. 30 BOC Operation with Front Wheel Slip
3 - 38 REAR DRIVELINE MODULERS
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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STEADY STATE, HIGH SPEED, NO WHEEL SLIP
The roller cage positions the rollers on the input shaft
flats during low and high speed overrunning and during
initial BOC lockup. The roller cage is rotating at input
shaft (propeller shaft) speed at all times. At low speeds,
the friction shoes (Fig. 31) are pressed against the fric-
tion ground via the garter spring (Fig. 32), creating a
drag force on the roller cage. The drag force positions
the cage, which in turn positions the rollers to one side
of the flat. The direction of this drag force (position of
the roller) is dependent on the input (propeller shaft)
rotational direction. Since the rollers are always in con-
tact with the outer race, due to centrifugal forces, the
rollers want to follow the outer race due to drag. During
overrunning operation, the outer race is rotating faster
than the input; causing the rollers to want to traverse
the flat from one side to the other. During low speeds,
the brake shoes counteract this effect. To avoid exces-
sive wear, the ground shoes are designed to lift off from
the friction ground due to centrifugal forces at higher
rotational speeds.
To keep the rollers in the overrunning position and
avoid undesired9high speed lockup9, a high speed
latch (Fig. 33) positions the cage before the ground
shoes lift off. A further explanation of the high speed
effects follows as well. Utilizing only the friction
shoes approach means that at high speed the
required ground shoe drag torque would cause exces-
sive brake shoe wear or the roller will begin tomigrate to the opposite side of the flat due to the
drag force of the outer race. This would result in sys-
tem lock-up. (Fig. 34) shows the BOC as it crosses
the speed where the brake shoe force is overcome by
the roller drag on the outer race. Notice that the
roller is locking up on the opposite side of the flat
and the cage supplies no force on the rollers.
Fig. 31 Front View of BOC
1 - GARTER SPRING
2 - FRICTION BRAKE SHOES
3 - FRICTION GROUND CONNECTED TO GROUND TAB
4 - INPUT SHAFT
Fig. 32 Location of the Grounding Element
1 - DIFFERENTIAL HOUSING
2 - GROUND TAB
3 - GARTER SPRING
Fig. 33 BOC High Speed Latch (Not Engaged)
1 - TOOTH (TWO PLACES)
2 - GARTER SPRING
3 - TABS AT BOTH ENDS FIT INTO SLOTS IN CAGE
4 - TWO PART DESIGN
RSREAR DRIVELINE MODULE3-39
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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This lock-up is not desired, and requires the use of
another mechanism to prevent the lock-up. The
device that prevents undesired high-speed lock-up is
called a9high speed latch9.
Similar to the friction shoes, the two-piece high-
speed latch will separate from each other at high
rotational speeds due to centrifugal effects. (Fig. 35)
shows the high speed latch engaged. The gap9x9
increases with speed, eventually locking into one of
the slots in the BOC shaft. When the high-speed
latch is activated (propeller shaft speed reaches X
amount), the cage is partially fixed, and cannot lock
on the wrong side of the flat as shown (Fig. 34). The
high speed latch is a one way device and does not
prevent high-speed lockup in the reverse direction. At
high speeds, the BOC provides the same function as
low speeds, transferring torque to the viscous coupler
only when front wheel slip overcomes the axle ratio
offset.
Fig. 34 BOC Operation During High Speed Lock-up Without High Speed Latch
Fig. 35 High Speed Latch Engaged
1 - CAGE FORCE EXERTED BY ROLLERS AT HIGH SPEED
3 - 40 REAR DRIVELINE MODULERS
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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At high speed, the rollers are forced outward to the
outer race because of centrifugal force. At high
speeds, the friction shoes can no longer prevent lock-
up. When the teeth on the high-speed latch engage
into the input shaft, it keeps the rollers centered
above the flats because the tabs on the latch are
locked into the cage. (Fig. 36) shows the roller config-
uration with the High-Speed Latch engaged.
On the BOC shaft, the high speed latch teeth lock
up in the grooved areas, shown in (Fig. 37), when the
turning speed reaches the critical value. (Fig. 37)
also shows the outer race/viscous coupler. Notice the
surface (outer race) the rollers mate against when
transferring torque.
DIFFERENTIAL ASSEMBLY
DESCRIPTION
The differential gear system divides the torque
between the axle shafts. It allows the axle shafts to
rotate at different speeds when turning corners.
Each differential side gear is splined to an axle
shaft. The pinion gears are mounted on a pinion
mate shaft and are free to rotate on the shaft. The
pinion gear is fitted in a bore in the differential case
and is positioned at a right angle to the axle shafts.
OPERATION
In operation, power flow occurs as follows:
²The pinion gear rotates the ring gear²The ring gear (bolted to the differential case)
rotates the case
²The differential pinion gears (mounted on the
pinion mate shaft in the case) rotate the side gears
²The side gears (splined to the axle shafts) rotate
the shafts
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig.
38).
Fig. 36 BOC Operation at High Speed with High
Speed Latch
Fig. 37 BOC Input Shaft
1 - GROOVED AREA (2 LOCATIONS)
2 - ROLLER MATING SURFACE
Fig. 38 Differential OperationÐStraight Ahead
Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
RSREAR DRIVELINE MODULE3-41
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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²Back-Up switch
²Brake Fluid Level
²B+ Connection Detection
²Engine Crank Signal (Diesel Engine Vehicles)
²Horn Input
²Ignition Switch Start Only
²Ignition Switch Run and Start Only
²Stop Lamp Sense
²Washer Fluid Level
²Windshield Wiper Park
DIAGNOSIS AND TESTING - FRONT CONTROL
MODULE
The Front Control Module (FCM) is a printed cir-
cuit board based module with a on-board micro-pro-
cessor. The FCM interfaces with other electronic
modules in the vehicle via the Programmable Com-
munications Interface (PCI) data bus. In order to
obtain conclusive testing the PCI data bus and all of
the electronic modules that provide inputs to, or
receive outputs from the FCM must be checked. All
PCI communication faults must be resolved prior to
further diagnosing any front control module related
issues.
The FCM was designed to be diagnosed with an
appropriate diagnostic scan tool, such as the DRB
IIIt. The most reliable, efficient, and accurate means
to diagnose the front control module requires the use
of a DRB IIItscan tool and the proper Body Diag-
nostic Procedures manual.
Before any testing of the FCM is attempted, the
battery should be fully charged and all wire harness
and ground connections inspected around the affected
areas on the vehicle.
REMOVAL
(1) Disconnect the positive and negative battery
cables from the battery.
(2) Remove the battery from the vehicle. Refer to
the procedure in Battery Systems.
(3) Using a long flat-bladed screwdriver, gently
twist the Integrated Power Module (IPM) retaining
clip outboard to free the IPM from its mounting
bracket (Fig. 6). Rotate IPM upward to access the
Front Control Module (FCM) retaining screws.
(4) Remove the front control module retaining
screws.
(5) Using both hands, pull the FCM straight from
the IPM assembly to disconnect the 49-way electrical
connector (Fig. 7) and remove the front control mod-
ule from the vehicle.
INSTALLATION
NOTE: Front Control Module must be programmed
to the correct radio EQ curve using the DRB IIIT.This will ensure that the audio system is operating
correctly.
(1) Install the Front Control Module (FCM) in the
Integrated Power Module (IPM) assembly by pushing
the 49-way electrical connector straight in.
(2) Install the FCM retaining screws. Torque the
screws to 1 N´m (7 in. lbs).
(3) Rotate the IPM assembly downward to secure
in mounting bracket.
Fig. 6 REMOVING INTELLIGENT POWER MODULE
Fig. 7 FRONT CONTROL MODULE
1 - FRONT CONTROL MODULE
8E - 8 ELECTRONIC CONTROL MODULESRS
FRONT CONTROL MODULE (Continued)
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between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up to
three minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
(4) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Integrated Power Module (IPM), one
at a time until the amperage reading becomes very
low, or nonexistent. Refer to the appropriate wiring
information in this service manual for complete Inte-
grated Power Module fuse, circuit breaker, and cir-
cuit identification. This will isolate each circuit and
identify the circuit that is the source of the high-am-
perage IOD. If the amperage reading remains high
after removing and replacing each fuse and circuit
breaker, disconnect the wire harness from the gener-
ator. If the amperage reading now becomes very low
or nonexistent, refer to Charging System for the
proper charging system diagnosis and testing proce-
dures. After the high-amperage IOD has been cor-
rected, switch the multi-meter to progressively lower
amperage scales and, if necessary, repeat the fuse
and circuit breaker remove-and-replace process to
identify and correct all sources of excessive IOD. It is
now safe to select the lowest milliampere scale of the
multi-meter to check the low-amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(5) Allow twenty minutes for the IOD to stabilize
and observe the multi-meter reading. The low-amper-
age IOD should not exceed twenty-five milliamperes
(0.025 ampere). If the current draw exceeds twenty-
five milliamperes, isolate each circuit using the fuse
and circuit breaker remove-and-replace process in
Step 4. The multi-meter reading will drop to within
the acceptable limit when the source of the excessive
current draw is disconnected. Repair this circuit as
required; whether a wiring short, incorrect switch
adjustment, or a component failure is at fault.STANDARD PROCEDURE - CHECKING BATTERY
ELECTROLYTE LEVEL
The following procedure can be used to check the
electrolyte level in a low-maintenance lead-acid bat-
tery.
(1) Unscrew and remove the battery cell caps with
a flat-bladed screw driver (Fig. 10).
WARNING: NEVER PUT YOUR FACE NEAR A GAS-
SING, HOT OR SWELLED BATTERY. SERIOUS PER-
SONAL INJURY MAY RESULT.
(2) Wearing safety glasses, look through the bat-
tery cell cap holes to determine the level of the elec-
trolyte in the battery. The electrolyte should be above
the hooks inside the battery cells (Fig. 11).
(3)Add only distilled wateruntil the electrolyte
is above the hooks inside the battery cells (Fig. 11).
REMOVAL - BATTERY
WARNING: A SUITABLE PAIR OF HEAVY DUTY
RUBBER GLOVES AND SAFETY GLASSES SHOULD
BE WORN WHEN REMOVING OR SERVICING A
BATTERY.
Fig. 10 BATTERY CELL CAP REMOVAL/
INSTALLATION - LOW-MAINTENANCE BATTERY
ONLY
1 - BATTERY CELL CAP
2 - BATTERY CASE
8F - 14 BATTERY SYSTEMRS
BATTERY (Continued)
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The switch is secured to the back of the seat cush-
ion side shield with two screws. However, the control
knobs for the seat switch unit must be removed
before the seat switch can be removed from the side
shield.
The power seat switch cannot be repaired. If one
switch is damaged or faulty, the entire power seat
switch unit must be replaced.
OPERATION
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the adjuster motor to
run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged. See the owner's
manual in the vehicle glove box for more information
on the power seat switch functions and the seat
adjusting procedures.
DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH
(1) Remove the power seat switch, refer to the
Switch Removal and Installation procedures in this
section.
(2) Using an ohmmeter, check pin #1 of the power
seat switch connector for continuity to ground. It
should be present, If OK go to Step3,IfNOTOK
repair the open ground circuit as required.
(3) Using an voltmeter, check pin #5 of the power
seat switch connector for approx. 12v. It should be
present, If OK go to Step4,IfNOTOKrepair the
open voltage supply circuit as required.
(4) Using an ohmmeter, verify the Seat Switch
Continuity Test table, using the seat switch connec-
tor (Fig. 3). If there is no continuity at any of the
switch positions, replace the power seat switch.
DRIVER SEAT SWITCH CONTINUITY TEST
TABLE
SWITCH
POSITIONCONTINUITY BETWEEN
PINS
DRIVER
OFF PIN5&4
PIN5&3
PIN5&2
PIN5&10
PIN5&9
PIN5&8
PIN5&7
PIN5&6
FRONT RISER
UPPIN5&6
PIN1&9
FRONT RISER
DOWNPIN5&9
PIN1&6
CENTER
SWITCH
FORWARDPIN5&3
PIN1&10
CENTER
SWITCH
REARWARDPIN5&10
PIN3&1
REAR RISER UP PIN5&7
PIN1&8
REAR RISER
DOWNPIN5&8
PIN1&7
RECLINER UP PIN5&2
PIN4&1
RECLINER
DOWNPIN5&4
PIN2&1
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) On models equipped with the eight-way power
seat, using a push pin remover or another suitable
wide flat-bladed tool, gently pry the power seat and
power recliner switch knobs off of the switch levers
(Fig. 4).
Fig. 3 Seat Switch Pin Call-Out
RSPOWER SEAT SYSTEM8N-55
DRIVER SEAT SWITCH (Continued)
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