2003 DODGE RAM pcm

2-3 SHIFT VALVE
The 2-3 shift valve mechanism (Fig. 265) consists
of the 2-3 shift valve, governor plug and spring, and
a throttle plug. After the 1-2 shift valve has com-
pleted its operation and applied the front band, line
pressure is directed to the 2-3 shift valve through the
connecting passages from the 1-2 shift valve. The line
pressure will then dead±end at land #2 until the 2-3
valve is ready to make its shift. Now that the vehicle
is in motion and under acceleration, there is throttle
pressure being applied to the spring side of the valve
and between lands #3 and #4.
As vehicle speed increases, governor pressure
increases proportionately, until it becomes great
enough to overcome the combined throttle and spring
pressure on the right side of the valve. Since the
throttle pressure end of the 2-3 shift valve is larger
in diameter than the 1-2 shift valve, the 2-3 shift will
always happen at a greater speed than the 1-2 shift.
When this happens, the governor plug is forced
against the shift valve moving it to the right. The
shift valve causes land #4 to close the passage sup-
plying throttle pressure to the 2-3 shift valve. With-
out throttle pressure present in the circuit now, the
governor plug will push the valve over far enough to
bottom the valve in its bore. This allows land #2 to
direct line pressure to the front clutch.
After the shift (Fig. 266), line pressure is directed
to the release side of the kickdown servo. This
releases the front band and applies the front clutch,shifting into third gear or direct drive. The rear
clutch remains applied, as it has been in the other
gears. During a manual ª1º or manual ª2º gear
selection, line pressure is sent between the two
lands of the 2-3 governor plug. This line pressure at
the governor plug locks the shift valve into the sec-
ond gear position, preventing an upshift into direct
drive. The theory for the blocking of the valve is the
same as that of the 1-2 shift valve.
If the manual ª2º or manual ª1º gear position is
selected from the drive position, the PCM will con-
trol the timing of the downshift by targeting for a
high governor pressure. When a safe vehicle speed
is reached, the PCM will switch to its normal con-
trol governor curve and the downshift will occur.
3-4 SHIFT VALVE
The PCM energizes the overdrive solenoid during
the 3-4 upshift (Fig. 267). This causes the solenoid
check ball to close the vent port allowing line pres-
sure from the 2-3 shift valve to act directly on the
3-4 upshift valve. Line pressure on the 3-4 shift
valve overcomes valve spring pressure moving the
valve to the upshift position (Fig. 268). This action
exposes the feed passages to the 3-4 timing valve,
3-4 quick fill valve, 3-4 accumulator, and ultimately
to the overdrive piston.
Fig. 265 2-3 Shift Valve - Before Shift
21 - 458 AUTOMATIC TRANSMISSION - 48REDR
VALVE BODY (Continued)

MANUAL VALVE
The manual valve (Fig. 272) is a relay valve. The
purpose of the manual valve is to direct fluid to the
correct circuit needed for a specific gear or driving
range. The manual valve, as the name implies, is
manually operated by the driver with a lever located
on the side of the valve body. The valve is connected
mechanically by either a cable or linkage to the gear-
shift mechanism. The valve is held in each of its
positions by a spring-loaded roller or ball that
engages the ªroostercombº of the manual valve lever.
CONVERTER CLUTCH LOCK-UP VALVE
The torque converter clutch (TCC) lock-up valve
controls the back (ON) side of the torque converter
clutch. When the PCM energizes the TCC solenoid to
engage the converter clutch piston, pressure is
applied to the TCC lock-up valve which moves to the
right and applies pressure to the torque converter
clutch.
CONVERTER CLUTCH LOCK-UP TIMING VALVE
The torque converter clutch (TCC) lock-up timing
valve is there to block any 4-3 downshift until the
TCC is completely unlocked and the clutch is disen-
gaged.
SHUTTLE VALVE
The assembly is contained in a bore in the valve
body above the shift valves. When the manual valve
is positioned in the Drive range, throttle pressure
acts on the throttle plug of the shuttle valve (Fig.
264) to move it against a spring, increasing the
spring force on the shuttle valve. During a part or
full throttle 1-2 upshift, the throttle plug is bottomed
by throttle pressure, holding the shuttle valve to the
right against governor pressure, and opening a
by±pass circuit. The shuttle valve controls the qual-
ity of the kickdown shift by restricting the rate of
fluid discharge from the front clutch and servo
release circuits. During a 3-2 kickdown, fluid dis-
charges through the shuttle by-pass circuit. When
the shuttle valve closes the by-pass circuit, fluid dis-
charge is restricted and controlled for the application
of the front band. During a 2-3 ªlift footº upshift, the
shuttle valve by-passes the restriction to allow full
fluid flow through the by-pass groove for a faster
release of the band.
Fig. 272 Manual Valve
DRAUTOMATIC TRANSMISSION - 48RE 21 - 463
VALVE BODY (Continued)

OVERDRIVE SWITCH
DESCRIPTION
The overdrive OFF (control) switch is located in
the shift lever arm (Fig. 106). The switch is a
momentary contact device that signals the PCM to
toggle current status of the overdrive function.
OPERATION
At key-on, overdrive operation is allowed. Pressing
the switch once causes the overdrive OFF mode to be
entered and the overdrive OFF switch lamp to be
illuminated. Pressing the switch a second time
causes normal overdrive operation to be restored and
the overdrive lamp to be turned off. The overdrive
OFF mode defaults to ON after the ignition switch is
cycled OFF and ON. The normal position for the con-trol switch is the ON position. The switch must be in
this position to energize the solenoid and allow a 3-4
upshift. The control switch indicator light illuminates
only when the overdrive switch is turned to the OFF
position, or when illuminated by the transmission
control module.
REMOVAL
(1) Using a plastic trim tool, remove the overdrive
off switch retainer from the shift lever (Fig. 107).
(2) Pull the switch outwards to release it from the
connector in the lever (Fig. 108)
Fig. 105 Output Speed Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
Fig. 106 Overdrive Off Switch
Fig. 107 Overdrive Off Switch Retainer
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH RETAINER
3 - PLASTIC TRIM TOOL
Fig. 108 Remove the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH
21 - 568 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
OVERDRIVE SWITCH (Continued)

(9) Fill the transmission with the recommended
fluid.
TRANSMISSION CONTROL
RELAY
DESCRIPTION
The relay is supplied fused B+ voltage, energized
by the TCM, and is used to supply power to the sole-
noid pack when the transmission is in normal oper-
ating mode.
OPERATION
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, the TCM energizes the
relay. Prior to this, the TCM verifies that the con-
tacts are open by checking for no voltage at the
switched battery terminals. After this is verified, the
voltage at the solenoid pack pressure switches is
checked. After the relay is energized, the TCM mon-
itors the terminals to verify that the voltage is
greater than 3 volts.
TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is part of
the solenoid module, which is mounted to the top of
the valve body inside the transmission.
The Transmission Range Sensor (TRS) has five
switch contact pins that:
²Determine shift lever position
²Supply ground to the Starter Relay in Park and
Neutral only.
²Supply +12 V to the backup lamps in Reverse
only.
The TRS also has an integrated temperature sen-
sor (thermistor) that communicates transmission
temperature to the TCM and PCM.
OPERATION
The Transmission Range Sensor (TRS) communi-
cates shift lever position to the TCM as a combina-
tion of open and closed switches. Each shift lever
position has an assigned combination of switch states
(open/closed) that the TCM receives from four sense
circuits. The TCM interprets this information and
determines the appropriate transmission gear posi-
tion and shift schedule.
There are many possible combinations of open and
closed switches (codes). Seven of these possible codes
are related to gear position and five are recognized
as ªbetween gearº codes. This results in many codes
which shouldnever occur. These are called
ªinvalidº codes. An invalid code will result in a DTC,
and the TCM will then determine the shift lever
position based on pressure switch data. This allows
reasonably normal transmission operation with a
TRS failure.
GEAR C5 C4 C3 C2 C1
ParkCL OP OP CL CL
Temp 1CL OP OP CL OP
ReverseOP OP OP CL OP
Temp 2OP OP CL CL OP
Neutral 1OP OP CL CL CL
Neutral 2OP CL CL CL CL
Temp 3OP CL CL CL OP
DriveOP CL CL OP OP
Temp 4OP CL OP OP OP
Manual 2CL CL OP OP OP
Temp 5CL OP OP OP OP
Manual 1CL OP CL OP OP
Fig. 125 Checking Torque Converter Seating-Typical
1 - SCALE
2 - STRAIGHTEDGE
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 581
TORQUE CONVERTER (Continued)

(4) Remove the front output shaft seal slinger by
bending (Fig. 85) the slinger ears away from the
transfer case.
(5) Using a suitable pry tool (Fig. 86), remove the
slinger from the output shaft using care not to dam-
age the shaft.(6) Using a screw and a slide hammer, remove the
front output shaft seal.
INSTALLATION
(1) Install the new front output shaft seal with
Installer MB991168A
(2) Install the front output shaft seal slinger with
Installer 8840. Install the slinger onto the shaft until
the tool contacts the rear of the output shaft.
(3) Install a new seal boot clamp onto the seal
boot.
(4) Install the seal boot and clamp onto the slinger
hub and tighten the clamp with Crimp Tool
C-4975-A.
(5) Install front propeller shaft (Refer to 3 - DIF-
FERENTIAL & DRIVELINE/PROPELLER SHAFT/
PROPELLER SHAFT - INSTALLATION).
POSITION SENSOR
DESCRIPTION
The transfer case position sensor is an electronic
device whose output can be interpreted to indicate
the transfer case's current operating mode. The sen-
sor consists of a five position, resistive multiplexed
circuit which returns a specific resistance value to
the Powertrain Control Module (PCM) for each trans-
fer case operating mode. The sensor is located on the
top of the transfer case, just left of the transfer case
centerline and rides against the sector plate rooster-
comb. The PCM supplies 5VDC (+/- 0.5V) to the sen-
sor and monitors the return voltage to determine the
sector plate, and therefore the transfer case, position.Fig. 85 Bend Slinger Ears
1 - SLINGER
2 - BEND UPWARD
Fig. 86 Remove Slinger From Shaft
1 - SLINGER
2-PRYTOOL
21 - 618 TRANSFER CASE - NV241 GENIIDR
FRONT OUTPUT SHAFT SEAL (Continued)

OPERATION
During normal vehicle operation, the Powertrain
Control Module (PCM) monitors the transfer case
position sensor return voltage to determine the oper-ating mode of the transfer case. Refer to the Operat-
ing Mode Versus Resistance table for the correct
resistance for each position (Fig. 87).
OPERATING MODE VERSUS RESISTANCE
SENSOR POSITION OPERATING MODE SENSOR RESISTANCE (ohms)
1 2H 1124-1243
2 4H 650-719
3 NEUTRAL 389-431
4 4L 199-221
5 NOT USED 57-64
REMOVAL
(1) Raise and support the vehicle.
(2) Disengage the transfer case position sensor
connector from the position sensor.
(3) Remove the position sensor from the transfer
case.
INSTALLATION
(1) Inspect the o-ring seal on the transfer case
position sensor. Replace the o-ring if necessary.
(2) Install the transfer case position sensor into
the transfer case. Torque the sensor to 20-34 N´m
(15-25 ft.lbs.).
(3) Engage the transfer case position sensor con-
nector to the position sensor.
(4) Lower vehicle.
(5) Verify proper sensor operation.
Fig. 87 Position Sensor Linear Movement
1 - POSITION 1 - 10mm  0.5mm
2 - POSITION 2 - 12mm  0.5mm
3 - POSITION 3 - 14mm  0.5mm
4 - POSITION 4 - 16mm  0.5mm
5 - POSITION 5 - 18mm  0.5mm
6 - POSITION 6 - 20mm 0.5mm - FULL EXTENSION
DRTRANSFER CASE - NV241 GENII 21 - 619
POSITION SENSOR (Continued)

POSITION SENSOR
DESCRIPTION
The transfer case position sensor is an electronic
device whose output can be interpreted to indicate
the transfer case's current operating mode. The sen-
sor consists of a five position, resistive multiplexed
circuit which returns a specific resistance value to
the Powertrain Control Module (PCM) for each trans-
fer case operating mode. The sensor is located on the
top of the transfer case, just left of the transfer case
centerline and rides against the sector plate rooster-comb. The PCM supplies 5VDC (+/- 0.5V) to the sen-
sor and monitors the return voltage to determine the
sector plate, and therefore the transfer case, position.OPERATION
During normal vehicle operation, the Powertrain
Control Module (PCM) monitors the transfer case
position sensor return voltage to determine the oper-
ating mode of the transfer case. Refer to the Operat-
ing Mode Versus Resistance table for the correct
resistance for each position (Fig. 96).
OPERATING MODE VERSUS RESISTANCE
SENSOR POSITION OPERATING MODE SENSOR RESISTANCE (ohms)
1 2H 1172-1195
2 4H 677-691
3 NEUTRAL 406-415
4 4L 208-213
5 NOT USED 60-61
REMOVAL
(1) Raise and support the vehicle.
(2) Disengage the transfer case position sensor
connector from the position sensor.
(3) Remove the position sensor from the transfer
case.
INSTALLATION
(1) Inspect the o-ring seal on the transfer case
position sensor. Replace the o-ring if necessary.
(2) Install the transfer case position sensor into
the transfer case. Torque the sensor to 20-34 N´m
(15-25 ft.lbs.).
(3) Engage the transfer case position sensor con-
nector to the position sensor.
(4) Lower vehicle.
(5) Verify proper sensor operation.
Fig. 96 Position Sensor Linear Movement
1 - POSITION 1 - 10mm  0.5mm
2 - POSITION 2 - 12mm  0.5mm
3 - POSITION 3 - 14mm  0.5mm
4 - POSITION 4 - 16mm  0.5mm
5 - POSITION 5 - 18mm  0.5mm
6 - POSITION 6 - 20mm 0.5mm - FULL EXTENSION
21 - 654 TRANSFER CASE - NV271DR

Pressure Diagnosis
Condition Possible Causes Correction
4. Faulty a/c compressor
clutch relay.4. See A/C Compressor Clutch Relay/Diagnosis
and Testing - Compressor Clutch Relay in this
group. Test the compressor clutch relay and relay
circuits. Repair the circuits or replace the relay, if
required.
5. Improperly installed or
faulty Fin Sensor.5. See Fin Sensor/Diagnosis and Testing in this
group. Reinstall or replace the Fin Sensor as
required.
6. Faulty a/c high pressure
transducer.6. See A/C High Pressure Transducer/Diagnosis
and Testing in this group. Test the a/c high
pressure transducer and replace, if required.
7. Faulty Powertrain Control
Module (PCM).7. (Refer to Appropriate Diagnostic Information).
Test the PCM and replace, if required.
Normal pressures, but A/C
Performance Test air
temperatures at center panel
outlet are too high.1. Excessive refrigerant oil in
system.1. See Refrigerant Oil/Standard Procedure -
Refrigerant Oil Level in this group. Recover the
refrigerant from the refrigerant system and
inspect the refrigerant oil content. Restore the
refrigerant oil to the proper level, if required.
2. Blend door inoperative or
sealing improperly.2. See Blend Door in this group. Inspect the
blend door for proper operation and sealing and
correct, if required.
3. Blend door actuator faulty
or inoperative.3. Perform blend door actuator diagnosis, replace
if faulty.
The low side pressure is
normal or slightly low, and
the high side pressure is too
low.1. Low refrigerant system
charge.1. See Plumbing/Diagnosis and Testing -
Refrigerant System Leaks in this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
2. Refrigerant flow through
the accumulator is restricted.2. See Accumulator in this group. Replace the
restricted accumulator, if required.
3. Refrigerant flow through
the evaporator coil is
restricted.3. See A/C Evaporator in this group. Replace the
restricted evaporator coil, if required.
4. Faulty compressor. 4. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is
normal or slightly high, and
the high side pressure is too
high.1. Condenser air flow
restricted.1. Check the condenser for damaged fins, foreign
objects obstructing air flow through the condenser
fins, and missing or improperly installed air seals.
Refer to Cooling for more information on air
seals. Clean, repair, or replace components as
required.
2. Inoperative cooling fan. 2. Refer to Cooling for more information. Test the
cooling fan and replace, if required.
3. Refrigerant system
overcharged.3. See Plumbing/Standard Procedure -
Refrigerant System Charge in this group. Recover
the refrigerant from the refrigerant system.
Charge the refrigerant system to the proper level,
if required.
24 - 4 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)