automatic transmission CHRYSLER CARAVAN 2003 Repair Manual

PRESSURE SWITCHES
The PCM/TCM relies on three pressure switches to
monitor fluid pressure in the L/R, 2/4, and OD
hydraulic circuits. The primary purpose of these
switches is to help the PCM/TCM detect when clutch
circuit hydraulic failures occur. The range for the
pressure switch closing and opening points is 11-23
psi. Typically the switch opening point will be
approximately one psi lower than the closing point.
For example, a switch may close at 18 psi and open
at 17 psi. The switches are continuously monitored
by the PCM/TCM for the correct states (open or
closed) in each gear as shown in the following chart:
PRESSURE SWITCH STATES
GEAR L/R 2/4 OD
ROPOPOP
P/N CL OP OP
1st CL OP OP
2nd OP CL OP
DOPOPCL
OD OP CL CL
OP = OPEN
CL = CLOSED
A Diagnostic Trouble Code (DTC) will set if the
PCM/TCM senses any switch open or closed at the
wrong time in a given gear.
The PCM/TCM also tests the 2/4 and OD pressure
switches when they are normally off (OD and 2/4 are
tested in 1st gear, OD in 2nd gear, and 2/4 in 3rd
gear). The test simply verifies that they are opera-
tional, by looking for a closed state when the corre-
sponding element is applied. Immediately after a
shift into 1st, 2nd, or 3rd gear with the engine speed
above 1000 rpm, the PCM/TCM momentarily turns
on element pressure to the 2/4 and/or OD clutch cir-
cuits to identify that the appropriate switch has
closed. If it doesn't close, it is tested again. If the
switch fails to close the second time, the appropriate
Diagnostic Trouble Code (DTC) will set.
REMOVAL
NOTE: If solenoid/pressure switch assembly is
being replaced, it is necessary to perform the TCM
Quick Learn Procedure. (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/TRANSMISSION
CONTROL MODULE - STANDARD PROCEDURE)
(1) Disconnect battery negative cable.
(2) Remove air cleaner assembly.(3) Disconnect solenoid/pressure switch assembly
connector.
(4) Disconnect input speed sensor connector.
(5) Remove input speed sensor (Fig. 305).
(6) Remove three (3) solenoid/pressure switch
assembly-to-transaxle case bolts (Fig. 306).
(7) Remove solenoid/pressure switch assembly and
gasket (Fig. 307). Use care to prevent gasket mate-
rial and foreign objects from become lodged in the
transaxle case ports.
Fig. 305 Input Speed Sensor
1 - INPUT SPEED SENSOR
Fig. 306 Solenoid/Pressure Switch Assembly-to-
Case Bolts
1 - BOLTS
2 - SOLENOID AND PRESSURE SWITCH ASSEMBLY
21 - 238 41TE AUTOMATIC TRANSAXLERS
SOLENOID/PRESSURE SWITCH ASSY (Continued)
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INSTALLATION
NOTE: If solenoid/pressure switch assembly is
being replaced, it is necessary to perform the TCM
Quick Learn Procedure. (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/TRANSMISSION
CONTROL MODULE - STANDARD PROCEDURE)
(1) Install solenoid/pressure switch assembly and
new gasket to transaxle (Fig. 307).
(2) Install and torque three (3) bolts (Fig. 306) to
13 N´m (110 in. lbs.).
(3) Install input speed sensor (Fig. 305) and torque
to 27 N´m (20 ft. lbs.).
(4) Connect input speed sensor connector.
(5) Install solenoid/pressure switch 8-way connec-
tor and torque to 4 N´m (35 in. lbs.).
(6) Install air cleaner assembly.
(7) Connect battery negative cable.
(8) If solenoid/pressure switch assembly was
replaced, perform TCM Quick Learn procedure.
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/TRANSMISSION CONTROL
MODULE - STANDARD PROCEDURE)
SPEED SENSOR - INPUT
DESCRIPTION
The Input Speed Sensor is a two-wire magnetic
pickup device that generates AC signals as rotation
occurs. It is threaded into the transaxle case (Fig.
308), sealed with an o-ring (Fig. 309), and is consid-
ered a primary input to the Powertrain/Transmission
Control Module.
Fig. 307 Solenoid/Pressure Switch Assembly and
Gasket
1 - SOLENOID/PRESSURE SWITCH ASSEMBLY
2 - GASKET
Fig. 308 Input Speed Sensor Location
1 - INPUT SPEED SENSOR
Fig. 309 O-Ring Location
1 - INPUT SPEED SENSOR
2 - O-RING
RS41TE AUTOMATIC TRANSAXLE21 - 239
SOLENOID/PRESSURE SWITCH ASSY (Continued)
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OPERATION
The Input Speed Sensor provides information on
how fast the input shaft is rotating. As the teeth of
the input clutch hub pass by the sensor coil (Fig.
310), an AC voltage is generated and sent to the
PCM/TCM. The PCM/TCM interprets this informa-
tion as input shaft rpm.
The PCM/TCM compares the input speed signal
with output speed signal to determine the following:
²Transmission gear ratio
²Speed ratio error detection
²CVI calculation
The PCM/TCM also compares the input speed sig-
nal and the engine speed signal to determine the fol-
lowing:
²Torque converter clutch slippage
²Torque converter element speed ratio
REMOVAL
(1) Disconnect battery negative cable.
(2) If necessary, disconnect and cap off transmis-
sion oil cooler lines.
(3) Disconnect input speed sensor connector.
(4) Unscrew and remove input speed sensor (Fig.
311).
(5) Inspect speed sensor o-ring (Fig. 312) and
replace if necessary.
INSTALLATION
(1) Verify o-ring is installed into position.
(2) Install and tighten input speed sensor to 27
N´m (20 ft. lbs.).
(3) Connect speed sensor connector.
(4) Connect battery negative cable.
Fig. 310 Sensor Relation to Input Clutch Hub
1 - INPUT SPEED SENSOR
2 - TRANSAXLE CASE
3 - INPUT CLUTCH HUB
Fig. 311 Input (Turbine) Speed Sensor
1 - INPUT SPEED SENSOR
Fig. 312 O-ring Location
1 - INPUT SPEED SENSOR
2 - O-RING
21 - 240 41TE AUTOMATIC TRANSAXLERS
SPEED SENSOR - INPUT (Continued)
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SPEED SENSOR - OUTPUT
DESCRIPTION
The Output Speed Sensor is a two-wire magnetic
pickup device that generates an AC signal as rotation
occurs. It is threaded into the transaxle case (Fig.
313), sealed with an o-ring (Fig. 314), and is consid-
ered a primary input to the Powetrain/Transmission
Control Module.
OPERATION
The Output Speed Sensor provides information on
how fast the output shaft is rotating. As the rear
planetary carrier park pawl lugs pass by the sensor
coil (Fig. 315), an AC voltage is generated and sent to
the PCM/TCM. The PCM/TCM interprets this infor-
mation as output shaft rpm.
The PCM/TCM compares the input and output
speed signals to determine the following:
²Transmission gear ratio
²Speed ratio error detection
²CVI calculation
VEHICLE SPEED SIGNAL
The vehicle speed signal is taken from the Output
Speed Sensor. The PCM converts this signal into a
pulse per mile signal and sends the vehicle speed
message across the communication bus to the BCM.
The BCM sends this signal to the Instrument Cluster
to display vehicle speed to the driver. The vehicle
speed signal pulse is roughly 8000 pulses per mile.
REMOVAL
(1) Disconnect battery negative cable.
(2) Raise vehicle on hoist.
(3) Disconnect output speed sensor connector.
(4) Unscrew and remove output speed sensor (Fig.
316).
(5) Inspect speed sensor o-ring (Fig. 317) and
replace if necessary.
Fig. 313 Output Speed Sensor
1 - OUTPUT SPEED SENSOR
Fig. 314 O-Ring Location
1 - OUTPUT SPEED SENSOR
2 - O-RING
Fig. 315 Sensor Relation to Planet Carrier Park Pawl
1 - OUTPUT SPEED SENSOR
2 - REAR PLANET CARRIER/OUTPUT SHAFT ASSEMBLY
3 - TRANSAXLE CASE
RS41TE AUTOMATIC TRANSAXLE21 - 241
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INSTALLATION
(1) Verify o-ring is installed into position (Fig.
317).
(2) Install and tighten input speed sensor to 27
N´m (20 ft. lbs.).
(3) Connect speed sensor connector.
(4) Connect battery negative cable.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 318) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
Fig. 316 Output Speed Sensor
1 - OUTPUT SPEED SENSOR
Fig. 317 O-ring Location
1 - OUTPUT SPEED SENSOR
2 - O-RINGFig. 318 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - CONVERTER CLUTCH DISC
6 - DRIVE PLATE
21 - 242 41TE AUTOMATIC TRANSAXLERS
SPEED SENSOR - OUTPUT (Continued)
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IMPELLER
The impeller (Fig. 319) is an integral part of the
converter housing. The impeller consists of curved
blades placed radially along the inside of the housing
on the transmission side of the converter. As the con-
verter housing is rotated by the engine, so is the
impeller, because they are one and the same and are
the driving member of the system.
Fig. 319 Impeller
1 - ENGINE FLEXPLATE 4 - ENGINE ROTATION
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION5 - ENGINE ROTATION
3 - IMPELLER VANES AND COVER ARE INTEGRAL
RS41TE AUTOMATIC TRANSAXLE21 - 243
TORQUE CONVERTER (Continued)
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STATOR
The stator assembly (Fig. 321) is mounted on a sta-
tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 322).
The stator contains an over-running clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the over-run-
ning clutch, the torque multiplication feature of the
torque converter is operational.
TORQUE CONVERTER CLUTCH (TCC)
The TCC (Fig. 323) was installed to improve the
efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock±free power transfer, it
is natural for all fluid couplings to slip. If the impel-
ler and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston was added to the turbine, and a friction mate-
rial was added to the inside of the front cover to pro-
vide this mechanical lock-up.
OPERATION
The converter impeller (Fig. 324) (driving member),
which is integral to the converter housing and bolted
to the engine drive plate, rotates at engine speed.
The converter turbine (driven member), which reacts
from fluid pressure generated by the impeller, rotates
and turns the transmission input shaft.
Fig. 321 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
Fig. 322 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINE
Fig. 323 Torque Converter Clutch (TCC)
1 - IMPELLER FRONT COVER
2 - THRUST WASHER ASSEMBLY
3 - IMPELLER
4-STATOR
5 - TURBINE
6 - PISTON
7 - FRICTION DISC
RS41TE AUTOMATIC TRANSAXLE21 - 245
TORQUE CONVERTER (Continued)
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TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and
turbine are rotating at about the same speed and the
stator is freewheeling, providing no torque multipli-
cation. By applying the turbine's piston to the front
cover's friction material, a total converter engage-
ment can be obtained. The result of this engagement
is a direct 1:1 mechanical link between the engine
and the transmission.
The engagement and disengagement of the TCC
are automatic and controlled by the Powertrain Con-
trol Module (PCM). The engagement cannot be acti-
vated in the lower gears because it eliminates the
torque multiplication effect of the torque converter
necessary for acceleration. Inputs that determine
clutch engagement are: coolant temperature, vehicle
speed and throttle position. The torque converter
clutch is engaged by the clutch solenoid on the valve
body. The clutch will engage at approximately 56
km/h (35 mph) with light throttle, after the shift to
third gear.
REMOVAL
(1) Remove transmission and torque converter
from vehicle. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 41TE - REMOVAL)
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
Check converter hub and drive notches for sharp
edges, burrs, scratches, or nicks. Polish the hub and
notches with 320/400 grit paper or crocus cloth if nec-
essary. The hub must be smooth to avoid damaging
the pump seal at installation.
(1) Lubricate converter hub and oil pump seal lip
with transmission fluid.
(2) Place torque converter in position on transmis-
sion.
CAUTION: Do not damage oil pump seal or bushing
while inserting torque converter into the front of the
transmission.(3) Align torque converter to oil pump seal open-
ing.
(4) Insert torque converter hub into oil pump.
(5) While pushing torque converter inward, rotate
converter until converter is fully seated in the oil
pump gears.
(6) Check converter seating with a scale and
straightedge (Fig. 326). Surface of converter lugs
should be 1/2 in. to rear of straightedge when con-
verter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
(8) Install the transmission in the vehicle. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 41TE - INSTALLATION)
(9) Fill the transmission with the recommended
fluid. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 41TE/FLUID - STANDARD PROCE-
DURE)TRANSMISSION CONTROL
RELAY
DESCRIPTION
The transmission control relay (Fig. 327) is located
in the Intelligent Power Module (IPM), which is
located on the left side of the engine compartment
between the battery and left fender.
Fig. 326 Checking Torque Converter Seating
1 - SCALE
2 - STRAIGHTEDGE
RS41TE AUTOMATIC TRANSAXLE21 - 247
TORQUE CONVERTER (Continued)
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OPERATION
The relay is supplied fused B+ voltage, energized
by the PCM/TCM, and is used to supply power to the
solenoid pack when the transmission is in normal
operating mode. When the relay is ªoffº, no power is
supplied to the solenoid pack and the transmission is
in ªlimp-inº mode. After a controller reset (ignition
key turned to the ªrunº position or after cranking
engine), the PCM/TCM energizes the relay. Prior to
this, the PCM/TCM verifies that the contacts are
open by checking for no voltage at the switched bat-
tery terminals. After this is verified, the voltage at
the solenoid pack pressure switches is checked. After
the relay is energized, the PCM/TCM monitors the
terminals to verify that the voltage is greater than 3
volts.
TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is mounted
to the top of the valve body inside the transaxle and
can only be serviced by removing the valve body. The
electrical connector extends through the transaxle
case (Fig. 328).
The Transmission Range Sensor (TRS) has four
switch contacts that monitor shift lever position and
send the information to the PCM/TCM.The TRS also has an integrated temperature sen-
sor (thermistor) that communicates transaxle tem-
perature to the TCM and PCM (Fig. 329).
OPERATION
The Transmission Range Sensor (TRS) (Fig. 328)
communicates shift lever position (SLP) to the PCM/
TCM as a combination of open and closed switches.
Each shift lever position has an assigned combination
of switch states (open/closed) that the PCM/TCM
receives from four sense circuits. The PCM/TCM inter-
prets this information and determines the appropriate
transaxle gear position and shift schedule.
Fig. 327 Transmission Control Relay Location
1 - TRANSMISSION CONTROL RELAY
2 - LEFT FENDER
3 - INTELLIGENT POWER MODULE (IPM)
4 - BATTERY
Fig. 328 Transmission Range Sensor (TRS)
Location
1 - TRANSMISSION RANGE SENSOR
Fig. 329 Transmission Temperature Sensor
1 - TRANSMISSION RANGE SENSOR
2 - TEMPERATURE SENSOR
21 - 248 41TE AUTOMATIC TRANSAXLERS
TRANSMISSION CONTROL RELAY (Continued)
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Since there are four switches, there are 16 possible
combinations of open and closed switches (codes).
Seven of these codes are related to gear position and
three are recognized as ªbetween gearº codes. This
results in six codes which should never occur. These
are called ªinvalidº codes. An invalid code will result
in a DTC, and the PCM/TCM will then determine the
shift lever position based on pressure switch data.
This allows reasonably normal transmission opera-
tion with a TRS failure.
TRS SWITCH STATES
SLP T42 T41 T3 T1
PCL CL CL OP
RCL OP OP OP
NCL CL OP CL
ODOP OP OP CL
3OP OP CL OP
LCL OP CL CL
TRANSMISSION TEMPERATURE SENSOR
The TRS has an integrated thermistor (Fig. 329)
that the PCM/TCM uses to monitor the transmis-
sion's sump temperature. Since fluid temperature
can affect transmission shift quality and convertor
lock up, the PCM/TCM requires this information to
determine which shift schedule to operate in. The
PCM also monitors this temperature data so it can
energize the vehicle cooling fan(s) when a transmis-
sion ªoverheatº condition exists. If the thermistor cir-
cuit fails, the PCM/TCM will revert to calculated oil
temperature usage.
CALCULATED TEMPERATURE
A failure in the temperature sensor or circuit will
result in calculated temperature being substituted for
actual temperature. Calculated temperature is a pre-
dicted fluid temperature which is calculated from a
combination of inputs:
²Battery (ambient) temperature
²Engine coolant temperature
²In-gear run time since start-up
REMOVAL
(1) Remove valve body assembly from transaxle.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 41TE/VALVE BODY - REMOVAL)
(2) Remove transmission range sensor retaining
screw and remove sensor from valve body (Fig. 330).
(3) Remove TRS from manual shaft.
INSTALLATION
(1) Install transmission range sensor (TRS) to the
valve body and torque retaining screw (Fig. 330) to 5
N´m (45 in. lbs.).
(2) Install valve body to transaxle. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
41TE/VALVE BODY - INSTALLATION)
TRD LINK
DESCRIPTION
The Torque Reduction Link (TRD) is a wire
between the PCM and TCM that is used by the TCM
to request torque management. Torque management
controls or reduces torque output of the engine dur-
ing certain shift sequences, reducing torque applied
to the transaxle clutches.
OPERATION
The torque management signal is basically a
12-volt pull-up supplied by the PCM to the TCM over
the torque reduction link (TRD). Torque management
is requested when the TCM pulses this signal to
ground. The PCM recognizes this request and
responds by retarding ignition timing, killing fuel
injectors, etc. The PCM sends a confirmation of the
request to the TCM via the communication bus.
Torque reduction is not noticable by the driver, and
usually lasts for a very short period of time.
If the confirmation signal is not received by the
TCM after two sequential request messages, a diag-
nostic trouble code will be set.
Fig. 330 Remove Transmission Range Sensor
1 - TRANSMISSION RANGE SENSOR
2 - MANUAL VALVE CONTROL PIN
3 - RETAINING SCREW
RS41TE AUTOMATIC TRANSAXLE21 - 249
TRANSMISSION RANGE SENSOR (Continued)
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