•
FUEL SYSTEM
14-79
OVERDRIVE/OVERRIDE SWITCH-PCM
INPUT
The overdrive/override switch is not used with
manual transmissions. On vehicles equipped with overdrive, the PCM reg
ulates the 3-4 overdrive upshift and downshift
through the overdrive solenoid. An override switch is located on the instrument panel. The overdrive/override switch is a momentary con
tact switch. The switch contacts are normally open. When the switch is activated, the PCM will receive a ground signal. The transmission will not enter over
drive when the operator presses the override switch.
The transmission downshifts if the operator presses
the override switch while in overdrive.
COOLANT TEMPERATURE SENSOR The coolant temperature sensor is not used with
manual transmissions.
The coolant temperature sensor (Fig. 6) monitors
engine coolant temperature. This input is used to in
hibit transmission upshift into overdrive when the
engine coolant temperature is below 16 degrees C (60
degrees F).
Fig.
6 Coolant
Temperature
Sensor
TRANSMISSION THERMO-SWITCH The transmission thermo-switch is not used with
manual transmissions.
The transmission thermo-switch opens when the
transmission fluid temperature is above 134°C (273°F). When the thermo-switch opens, the trans
mission will not shift into overdrive. The transmis sion downshifts if it is in overdrive when the thermo-
switch opens. Once the thermo-switch opens, it will
not close until transmission fluid temperature drops
to 116°C (240°F). The switch is located in the trans mission-to-radiator cooling line (Fig. 7).
PARK/NEUTRAL SWITCH-PCM
INPUT
The park/neutral switch (Fig. 8) is located on the
automatic transmission housing. It provides an input
THERMO SWITCH
J9214-62
Fig.
7
Transmission
Thermo-Switch—Typical to the PCM. The input indicates if the automatic
transmission is in park, neutral or a drive gear se lection.
If transmission is in overdrive and operator shifts
vehicle into neutral, the overdrive solenoid will be de-energized. Normal PCM operation will resume
when the transmission is shifted back into drive po sition.
The PCM uses the park/neutral switch input when
determining speed control strategy. The PCM will
disable the speed control if the operator shifts the
transmission into neutral. The speed control will
have to be reset once the vehicle is placed back into drive.
The park/neutral switch is sometimes referred to as
the neutral safety switch. Refer to Group 21 Trans missions for adjustment, replacement and test infor
mation.
Fig.
8 Park/Neutral Switch—Typical
POWER
GROUND-PCM
INPUT
Provides a common ground for power devices (sole
noid and relay).
14 - 80
FUEL SYSTEM
•
SCI
RECEIVE-PCM
INPUT
The serial communication interface (SCI) receive
and transmit outputs allow the PCM to communicate
with the DRB II scan tool.
SENSOR
RETURN-PCM
INPUT
Sensor return provides a low noise ground refer
ence for all system sensors.
SIGNAL
GROUND-PCM
INPUT
Provides a common ground for the input signals.
SPEED
CONTROL-PCM
INPUT
The PCM regulates the speed control system based
on inputs it receives. The speed control operating
range is from 35 to 85 mph. Inputs that effect speed control operation are:
• Park/neutral switch
• Vehicle speed sensor
• Throttle position sensor
• Engine speed sensor
• Brake switch
THROTTLE
POSITION SENSOR (TPS) —PCM
INPUT
The throttle position sensor is not used with man
ual transmissions. The throttle position sensor (TPS) is mounted on
the top of the fuel injection pump (Fig. 9). The TPS
provides an input to the PCM. It senses how far the
throttle is open (past the idle position). The PCM uses the TPS input, along with vehicle speed sensor and engine speed sensor inputs to determine 3-4 up
shift (overdrive) and 4-3 downshift. The TPS is a potentiometer. The PCM supplies 5
volts to the sensor. TPS output to the PCM varies
from approximately 1.0 volt at idle to 3.5 volts at
wide open throttle (WOT). T
J9114-237
Fig.
9
Throttle
Position
Sensor
VEHICLE SPEED SENSOR-PCM
INPUT
The vehicle speed sensor (Fig. 10) is located in the
extension housing of the transmission (2WD) or on the transfer case extension housing (4WD). A signal
is sent from this sensor, along with signals from both
the TPS and the engine speed sensor, to the PCM.
The PCM will then use this information to determine
when to shift into and out of overdrive.
The speed sensor is also used in determining speed
control set, decelerate, accelerate, maximum set
speed (85 mph) and minimum set speed (35 mph) op
erations.
VEHICLE
SPEED
SENSOR
Fig.
10 Vehicle
Speed
Sensor—Typical Location
WATER-IN-FUEL SENSOR-PCM
INPUT
The water-in-fuel (WIF) sensor is located at the
bottom of the fuel/water separator filter (Fig. 11). The sensor sends an input to the PCM when it senses
water in the fuel. The PCM looks at the water-in-fuel sensor signal when the ignition key is put in the ON
position. It also monitors the input at the end of the intake heater post-heat cycle. The PCM turns the water-in-fuel indicator lamp to
the ON position if water is detected in the fuel. The
water-in-fuel indicator lamp is located in the instru ment panel.
J91 14-85
Fig.
11 Water-in-Fuel
Sensor
14 - 82
FUEL 'SYSTEM
—. — ~—— — «
INTAKE HEATER CYCLE CHART
Intake
featperafwre
Preheat
Cycle
Time
Ignition
l£ey ON
Engine
Not
Running
Pestheat
Cycle
Ignition
Key ON
Snglne Running
Above
15
°C
(59
°F)
0 Seconds
No
-8°C(18°F)to
15°C (59
°F)
10
Seconds
Yes
-17°C(1
°F)
-9
°C(]6°F)
15
Seconds
Yes
«2d°C(-15°F)
to-18°C(0
°F) 17.5
Seconds
Yes
Below-26
°C (-15
*F)
20 Seconds
Yes
J9114-239
AUTO SHUT DOWN (ASD) RELAY-PCM OUTPUT
The ASD relay is located in the engine compart
ment (Fig. 14).
TORQUE CONVERTER
CLUTCH RELAY A/C CLUTCH RELAY STARTER RELAY
AUTO SHUTDOWN RELAY FUEL PUMP RELAY DATA LINK
CONNECTOR
POWERTRAIN
CONTROL MODULE
J9314-164
Fig.
14 Relay Location—Typical The ASD relay supplies battery voltage to the gen
erator field winding to provide regulation of the
charging system. The ground circuit for the ASD re
lay is controlled by the PCM. The PCM operates the
relay by switching the ground circuit on and off.
MALFUNCTION INDICATOR LAMP-PCM OUTPUT
The malfunction indicator lamp (formerly referred
to as the check engine lamp) illuminates at the bot
tom of the instrument panel each time the ignition
key is turned on. It will stay on for three seconds as
a bulb test. If the powertrain control module (PCM) receives an
incorrect signal, or no signal from certain sensors or emission related systems, the lamp is turned on. This
is a warning that the PCM has recorded a system or
sensor malfunction. In some cases, when a problem is
declared, the PCM will go into a limp-in mode. This is an attempt to keep the system operating. It signals
an immediate need for service.
The lamp can also be used to display a diagnostic
trouble code (DTC). Cycle the ignition switch
On-Off-
On-Off-On within three seconds and any codes stored
in the PCM memory will be displayed. This is done
in a series of flashes representing digits. Refer to On-
Board Diagnostics in the General Diagnosis section
of this group for more information.
OVERDRIVE
INDICATOR LAMP-PCM OUTPUT
Indicates the state of the overdrive defeat switch
on the instrument panel.
OVERDRIVE
S0LEN0ID-PCM OUTPUT
The overdrive solenoid is used on vehicles that
have an automatic transmission. The solenoid is op erated by the PCM. It controls shifting in and out of
overdrive through the overdrive solenoid. Refer to Group 21 for overdrive solenoid service.
SCI
TRANSMIT—PCM OUTPUT
SCI Transmit is the serial data communication
transmit circuit for the DRB II scan tool. The PCM
transmits data to the DRB II through the SCI Trans
mit circuit.
SPEED
C0NTR0L-PCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. The vacuum solenoid main
tains vacuum at a required pressure to resume, set or accelerate the speed control system. The vent so
lenoid allows vacuum to bleed off during decelera
tion, when the brakes are applied, or the
transmission is shifted into park or neutral.
TACHOMETER-PCM
OUTPUT
This output generates the necessary signal needed
to operate a dealer installed tachometer (if equipped).
The input for this signal is from the engine speed sensor.
WAIT-TO-START LAMP-PCM OUTPUT
The wait-to-start lamp is turned on and off by the
PCM based on the charge air temperature sensor in
put. The light is turned on when the ignition is first ac
tivated. It will remain on for two seconds as a bulb
test. If the PCM reads intake manifold air tempera
ture below 15°C (59°F), it will turn the wait-to-start light on for the intake heater preheat cycle. The
light stays on until the preheat cycle is over. The wait-to-start light will flash on and off if the
charge air temperature sensor input to the PCM is
•
FUEL
SYSTEM
14 - 87
ENGINE
WARM-UP
• The PCM may start the air intake heater post-heat
cycle depending on intake air temperature. If manifold air temperature was at or below 15°C (59°F) when the
ignition switch was turned on, the cycle is started.
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F).
• If the coolant temperature is below 16°C (60° F),
the transmission will not be allowed to enter over drive (automatic transmission).
• The PCM will turn on the water-in-fuel lamp if a signal is received from the water-in-fuel sensor.
CRUISE
OR
IDLE
• The PCM monitors intake manifold air tempera
ture through the charge temperature sensor input. • If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en ergized until the air temperature switch opens. The switch opens when intake manifold air temperature
is above 32°C (90°F).
• The air intake heater post-heat cycle will be com
pleted, if it is not already over.
• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over drive (automatic transmission).
• If the transmission thermo-switch is open, the
transmission will not be allowed to enter into over
drive (automatic transmission). If the switch opens
when the vehicle is in overdrive, the transmission
will be downshifted. The transmission thermo-switch opens at 134°C (273°F).
• The thermo-switch will close once the transmission
fluid temperature drops to 116°C (240°F). • The PCM will turn on the water-in-fuel lamp if a signal is received from the water-in-fuel sensor.
ACCELERATION
• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over
drive (automatic transmission).
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F). • If the transmission thermo-switch is open, the
transmission will not be allowed to enter into over
drive (automatic transmission). If the switch opens
when the vehicle is in overdrive, the transmission
will be downshifted. The transmission thermo-switch opens at 134°C (273°F). The thermo-switch will close
once the transmission fluid temperature drops to 116°C (240°F).
• The PCM will turn on the water-in-fuel lamp if a
signal is received from the water-in-fuel sensor.
• If the speed control system resume/accelerate func
tion is being used, the PCM will only allow the vehi
cle to accelerate at a predetermined rate. If a speed
control has been set and the resume/accelerate but
ton is momentarily pushed in, the PCM will increase
vehicle speed by two miles per hour.
• If the brakes are applied, the PCM will disable the
speed control.
DECELERATION
• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over drive (automatic transmission).
• If the transmission thermo-switch is open, the trans
mission will not be allowed to enter into overdrive (au
tomatic transmission). If the switch opens when the
vehicle is in overdrive, the transmission will be down shifted. The transmission thermo-switch opens at 134°C (273°F). The thermo-switch will close once the transmis
sion fluid temperature drops to 116°C (240°F).
• The PCM will turn on the water-in-fuel lamp if a
signal is received from the water-in-fuel sensor.
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F).
• If the speed control system coast/set function is be
ing used, the PCM will only allow the vehicle to de celerate at a predetermined rate. If the coast/set
switch is pushed while the system is operating, the
PCM will set speed control to the rate the vehicle is
traveling at when the switch is released. • If the brakes are applied, the PCM will disable the speed control.
IGNITION SWITCH
OFF
• When the ignition switch is turned to the off posi
tion, the PCM still receives battery voltage through
the battery input. Battery voltage is needed to keep
PCM memory alive. The PCM memory stores diag nostic trouble code (DTC) messages and the mini
mum TPS value from the previous key-on.
OVERDRIVE/OVER-RIDE
SWITCH
(AUTO
ONLY) CO
oo
c/3 -<
LSTARJERJ^
_ j
J9314-184
5.91.
DIESEL SYSTEM SCHEMATIC •
CAV
WIRE
COLOR DESCRIPTION
CAV
WIRE
COLOR DESCRIPTION
1 WT/BK
WATER-IN-FUEL SENSOR 37 OVERDRIVE LAMP SIGNAL
2 TN/BK
COOLANT SENSOR (AUTOMATIC TRANSMISSION ONLY) 38
3 RD BATTERY
39
4
BK/LB*
SENSOR RETURN 40
5 BK/WT
SIGNAL GROUND 41
6 VT/WT*
5 VOLT SUPPLY 42
7 TN/YL 8 VOLT INPUT 43 GR/LB TACHOMETER
8 44
9 DB
IGNITION SENSE 45 LG DATA LINK RECIEVE
10 RD/WT*
OVERDRIVE OVERRIDE 46
11 BK/TN POWER GROUND
47 WT/OR* VEHICLE SENSOR
12 BK/TN
POWER GROUND 48 BR/RD* SPEED CONTROL COAST/SET SWITCH
13 49 YL/RD* SPEED CONTROL ON/OFF SWITCH
14 50 WT/LG* SPEED CONTROL RESUME/ACCEL SWITCH
15 OR/BK* HEATER
#2
RELAY 51 DB/YL ASD RELAY
16 YL/BK HEATER #1 RELAY 52
17 53 LG/RD* SPEED CONTROL VENT SOLENOID
18 54 BK/PK* WATER-IN-FUEL LAMP
19 55 OR/LG* OVERDRIVE SOLENOID
20 DG GENERATOR FIELD 56 DG/WT WAIT-TO-START LAMP
21 BK/RD
CHARGE (INTAKE) AIR TEMPERATURE SENSOR 57 DG/OR ASD SENSE
22
OR/DB*
THROTTLE POSITION SENSOR 58
23 59
24 GY/BK
REFERENCE PICKUP 60
25 PK
DATA LINK TRANSMIT WIRE COLOR CODES LB
LIGHT BLUE VT VIOLET
26 BK BLACK LG LIGHT GREEN WT
WHITE
27 BR
A/C CLUTCH REQUEST BR BROWN OR ORANGE
YL YELLOW
28 LG/RD THERMO SWITCH DB DARK BLUE PK PINK *
WITH TRACER
29 WT/PK* BRAKE SWITCH DG DARK GREEN
RD RED
30 BR/YL*
PARK/NEUTRAL SWITCH GY GRAY TN TAN
31 ruin
32 BK/PK*
MALFUNCTION INDICATOR LAMP
n
33 TN/RD*
SPEED CONTROL VACUUM SOLENOID CONNECTOR
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1 1
HI
173456789
10 J/^"*\
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VlX
21
22
23
24
25
26
27
28
29
30
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II
12 13
14 15
16 17 18
19 20
\
34 DB/OR
WIDE OPEN THROTTLE (A/C) TERMINAL
J//000OOOOOOO
1 1
HI
173456789
10 J/^"*\
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oooooooooo (1 Oj]
VlX
21
22
23
24
25
26
27
28
29
30
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31
32 33 34 35 36 37 38 39 40
1JU
35 SHOWN \\\
41 42 43 44 45 46 47 48 49
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36
Li
J9314-185
PCM
CONNECTOR CAVITY DESCRIPTION
21
- 78
AUTOMATIC TRANSMISSION-32RH/36RH/37RH/42RH/46RH
G1NERAL
INFORMATION
—42RH/46RH
INDEX
page
Components Unique
to
Diesel Version
of
46RH
. 81
Description
78
Fourth
Gear Overdrive Components
81
Fourth
Gear Overdrive Operation
. 82
Gear Ratios
81
page
Hydraulic Controls
. 83
Recommended
Fluid
81
Torque Converter
81
Transmission
Identification . 81
DESCRIPTION
The Chrysler 42RH/46RH are four-speed, auto
matic transmissions. Fourth gear is an overdrive
range. The 42RH is used for 3.9L and 5.2L engine applications. The 46RH is used with 5.2L/5.9L gas
engines. A heavy duty version of the 46RH is used
with the 5.9L Cummins turbo-diesel engine. The 42RH/46RH is a dual unit design. The assem
bly consists of a three speed automatic transmission
with an overdrive unit attached at the rear (Figs. 1 and 2). First through third gear ranges are provided
by the clutches, bands, overrunning clutch and plan etary gear set in the transmission. Fourth gear range
is provided by the overdrive unit. Overdrive ratio is
0.69:1.
The overdrive unit contains an overdrive clutch, di
rect clutch, planetary gear set and overrunning clutch. The overdrive clutch is applied in fourth gear
only. The direct clutch is applied in all ranges except
fourth gear.
The governor and park lock assemblies are located
inside the overdrive unit. The unit must be removed
and disassembled for service access to the park lock and governor components.
Fourth gear is controlled by a manually operated
switch in the instrument panel. The switch is in cir
cuit with the overdrive solenoid (on the valve body)
and the powertrain control module. In the On posi
tion, current flows through the switch to the solenoid
for the 3-4 shift sequence. The transmission must be in third gear before a 3-4 upshift will occur.
The overdrive solenoid will not be energized and a
3-4 upshift will not occur when the control switch is
in the OFF position.
•
AUTOMATIC
TRANSMISSION—32RH/36RH/37RH/42RH/46RH
21 - 81
TORQUE
CONVERTER
A three element torque converter
is
used
for all ap
plications.
The
converter consists
of the
impeller,
sta-
tor
and
turbine.
The
converter also contains
an
overrunning clutch
and a
modulated converter clutch
mechanism.
The converter used with
1993,
42RH transmissions
is
new. The
converter
hub was
changed
to
accept
the
new style drive flats
on the oil
pump inner gear.
The
new style converter
is not
interchangeable with pre
vious designs.
The converter modulated clutch consists
of a
slid
ing clutch piston, clutch springs
and the
clutch disc
friction material.
The
clutch provides optimum
torque transfer
and
economy when engaged.
The clutch disc
is
attached
to the
converter front
cover.
The
clutch piston
and
clutch springs
are at
tached
to the
turbine
hub. The
springs dampen
en
gine firing impulses
and
loads during
the
initial
phase
of
converter clutch engagement.
Clutch engagement
is
controlled
by the
converter
clutch valve
and
solenoid. Both
are
located
on the
transmission valve body. Clutch engagement occurs in drive range
at
speeds above approximately 30-35
mph.
The clutch provides reduced engine speed
and
greater fuel economy when engaged. Clutch engage
ment also provides reduced transmission fluid tem
peratures.
COMPONENTS
UNIQUE
TO
DIESEL VERSION
OF
46RH
Planetary
Gears
The transmission
and
overdrive planetary gear car
riers
in the
diesel version
of the
46RH
are
heavy duty components.
The
transmission planetary carriers have four pinion gears.
The
carrier
in the
over
drive compounder
has
five pinion gears.
The
heavy
duty planetary units
are
unique
to the
diesel 46RH.
Clutch
Packs
Clutch packs used
in the
diesel version
of the
46RH contain
the
following number
of
discs
and
plates:
• transmission front/rear clutch
has 4
discs
and 5
steel plates
• overdrive clutch
has 5
discs
and 6
steel plates
• overdrive direct clutch
has 8
discs
and 9
steel
plates
Governor
Weight
Assembly
The governor weight assembly
in the
diesel 46RH
is made
of
alloyed brass.
The
diesel weight assembly
is easily identified
by the
distinctive gold color
of the
alloyed material.
The
heavier weight assembly pro
vides
the
shift points needed
to
offset lower operating speeds
of a
diesel engine. The alloyed weight assembly
is
unique
to the
diesel
46RH.
It is not
interchangeable with
the
weight
as
semblies used
in gas
engine versions.
Diesel
Thermo
Switch
Fourth gear operation
in the
diesel 46RH
is
also
controlled
by two
temperature sensitive thermo- switches.
The first thermo-switch
is the
engine coolant tem
perature switch. This switch prevents overdrive fourth gear operation when engine coolant tempera
ture
is
below approximately
65° F.
The second thermo-switch directly monitors trans
mission fluid temperature.
The
switch will either
downshift
the
transmission
to
third gear,
or
prevent a
3-4
upshift when fluid temperature exceeds
270-275°
F.
The fluid temperature switch
is
located
in a
boss
built into
the
cooler outlet line.
The
boss
and
switch are located approximately
2-3
inches from
the
outlet
line fitting
in the
transmission case.
The engine coolant
and
fluid temperature switches
are
in
circuit with
the
overdrive control switch
in the
instrument panel.
GEAR RATIOS
42RH forward gear ratios
are:
First gear
=
2.74:1
Second gear
= 1.54:1
Third gear
= 1.00:1
Fourth gear
=
0.69:1.
46RH forward gear ratios
are:
First gear
=
2.45:1 Second gear
= 1.45:1
Third gear
= 1.00:1
Fourth gear
=
0.69:1.
RECOMMENDED
FLUID
The recommended
and
preferred fluid
for
42RH/
46RH transmissions
is
Mopar
ATF
Plus, type
7176.
Use Mopar Dexron
II
only when
ATF
Plus
is not
readily available.
TRANSMISSION
IDENTIFICATION
The transmission part
and
identification numbers
and codes
are
stamped
on the
left side
of the
case
just above
the oil pan
gasket surface
(Fig. 3).
The first letter/number group
is the
assembly part
number.
The
next number group
the
transmission
build date.
The
last number group
is the
transmis sion serial number. Refer
to
this information when
ordering replacement parts.
FOURTH
GEAR OVERDRIVE COMPONENTS
42RH/46RH models have three transmission shafts.
An intermediate shaft
is
positioned between
the in
put
and
output shafts.
The
output shaft
is in the