engine coolant DODGE RAM 2003 Service Manual PDF

(6) Disconnect washer bottle wiring and hose.
(7) Remove fan shroud assembly.
(8) Remove A/C compressor and genterator brace.
(9) Remove idler pulleys.
(10) Remove belt tensioner assembly.
(11) Remove upper and lower radiator hoses.
(12) Remove heater hoses.
(13) Remove water pump mounting bolts and
remove pump.INSTALLATION
(1) Install water pump and mounting bolts.
Tighten moubting bolts to 24 N´m (18 ft. lbs.).
(2) Install heater hoses.
(3) Install upper and lower radiator hoses.
(4) Install belt tensioner assembly.
(5) Install idler pulleys.
(6) Install A/C compressor and alternator brace.
Tighten bolt and nuts to 28 N´m (21 ft. lbs.).
(7) Install fan shroud assembly.
(8) Connect washer bottle wiring and hose.
(9) Install coolant fill bottle.
(10) Install fan clutch assembly.
(11) Install serpentine belt.
(12) Connect negative battery cable.
(13) Fill coolant.
(14) Pressure test coolant system
DRENGINE 7 - 71
WATER PUMP - 5.7L (Continued)

ers are supplied as standard equipment on diesel
engine powered models when equipped with an auto-
matic transmission.
The main water-to-oil transmission oil cooler is
mounted to a bracket on the intake side of the engine
(Fig. 4).
The air-to-oil cooler is located in front of and to the
left side of the radiator (Fig. 5).
OPERATION
The transmission oil is routed through the main
cooler first, then the auxiliary cooler where addi-
tional heat is removed from the transmission oil
before returning to the transmission. The cooler has
an internal thermostat that controls fluid flow
through the cooler. When the transmission fluid is
cold (less then operating temperature), the fluid is
routed through the cooler bypass. When the trans-
mission fluid reaches operating temperatures and
above, the thermostat closes off the bypass allowing
fluid flow through the cooler. The thermostat is ser-
vicable.
REMOVAL
REMOVALÐAIR TO OIL COOLER
(1) Remove Charge Air Cooler (Refer to 11 -
EXHAUST SYSTEM/TURBOCHARGER SYSTEM/
CHARGE AIR COOLER AND PLUMBING -
REMOVAL).(2) Place a drain pan under the oil cooler.
(3) Raise the vehicle.
(4) Disconnect the oil cooler quick-connect fittings
from the transmission lines.
(5) Remove the charge air cooler-to-oil cooler bolt
(Fig. 6).
(6) Remove two mounting nuts.
(7) Remove the oil cooler and line assembly
towards the front of vehicle. Cooler must be rotated
and tilted into position while removing.
REMOVALÐWATER TO OIL COOLER
CAUTION: If a leak should occur in the water-to-oil
cooler mounted to the side of the engine block,
engine coolant may become mixed with transmis-
sion fluid. Transmission fluid may also enter engine
cooling system. Both cooling system and transmis-
sion should be drained and inspected in case of oil
cooler leakage.
(1) Disconnect both battery negative cables.
(2) Remove starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - REMOVAL).
(3) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(4) Disconnect coolant lines from cooler.
Fig. 4 Transmission Water-To-Oil CoolerÐDiesel
EngineÐTypical
1 - TRANSMISSION WATER-TO-OIL COOLER
Fig. 5 Auxiliary Transmission Oil CoolerÐDiesel
Engine
1 - MOUNTING BOLTS
2 - RADIATOR
3 - QUICK-CONNECT FITTINGS
4 - TRANSMISSION OIL COOLER
7 - 74 TRANSMISSIONDR
TRANS COOLER - 5.9L DIESEL (Continued)

(5) Disconnect transmission oil lines from cooler.
Plug cooler lines to prevent oil leakage.
(6) Remove cooler bracket to transmission bolt.
(7) Remove two cooler bracket to cooler bolts.
(8) Remove cooler assembly from vehicle. (Fig. 7)
INSTALLATION
INSTALLATIONÐAIR TO OIL COOLER
(1) Carefully position the oil cooler assembly to the
vehicle.
(2) Install two nuts and one bolt. Tighten to 11
N´m (95 in. lbs.) torque.
(3) Connect the quick-connect fittings to the trans-
mission cooler lines.
(4) Install Charge Air Cooler (Refer to 11 -
EXHAUST SYSTEM/TURBOCHARGER SYSTEM/
CHARGE AIR COOLER AND PLUMBING -
INSTALLATION).
(5) Start the engine and check all fittings for
leaks.(6) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
INSTALLATION
(1) Position oil cooler on cylinder block.
(2) Install two mounting bolts to cooler at the cyl-
inder block. Torque bolts to 77N´m (57 ft. lbs.)
(3) Install cooler bracket to transmission adapter
bolt. Tighten to 24N´M (18 ft. lbs.).
(4) Connect transmission oil lines to cooler.
(5) Connect coolant hoses to cooler.
(6) Install starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - INSTALLA-
TION).
(7) Connect battery negative cables.
(8) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(9) Check transmission oil level and fill as neces-
sary (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
Fig. 6 Auxiliary Transmission Oil CoolerÐDiesel
Engine
1 - MOUNTING BOLTS
2 - RADIATOR
3 - QUICK-CONNECT FITTINGS
4 - TRANSMISSION OIL COOLER
Fig. 7 Transmission Water-To- Oil CoolerÐDiesel
1 - TRANSMISSION WATER-TO-OIL COOLER
DRTRANSMISSION 7 - 75
TRANS COOLER - 5.9L DIESEL (Continued)

ENGINE CONTROL MODULE
DESCRIPTION - ECM
The Engine Control Module (ECM) is bolted to the
left side of the engine below the intake manifold (Fig.
2).
OPERATION - ECM
The main function of the Engine Control Module
(ECM) is to electrically control the fuel system. The
Powertrain Control Module (PCM)does not control
the fuel system.
The ECM can adapt its programming to meet
changing operating conditions.If the ECM has
been replaced, flashed or re-calibrated, the
ECM must learn the Accelerator Pedal Position
Sensor (APPS) idle voltage. Failure to learn
this voltage may result in unnecessary diagnos-
tic trouble codes. Refer to ECM Removal/Instal-
lation for learning procedures.
The ECM receives input signals from various
switches and sensors. Based on these inputs, the
ECM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to asECM Outputs.The sensors
and switches that provide inputs to the ECM are
consideredECM Inputs.NOTE: ECM Inputs:
²Accelerator Pedal Position Sensor (APPS) Volts
²APPS1 Signal Ð For off engine APPS
²APPS2 Signal Ð For off engine APPS
²APPS Idle Validation Switches #1 and #2
²Battery voltage
²Camshaft Position Sensor (CMP)
²CCD bus (+) circuits
²CCD bus (-) circuits
²Crankshaft Position Sensor (CKP)
²Data link connection for DRB scan tool
²Engine Coolant Temperature (ECT) sensor
²Ground circuits
²Fuel Pressure Sensor
²Battery Temperature
²Fan speed
²Inlet Air Temperature Sensor/Pressure Sensor
²Intake Air Temperature Sensor/MAP Sensor
²Oil Pressure SWITCH
²Power ground
²Sensor return
²Signal ground
²Water-In-Fuel (WIF) sensor
NOTE: ECM Outputs:
After inputs are received by the ECM, certain sen-
sors, switches and components are controlled or reg-
ulated by the ECM. These are consideredECM
Outputs.These outputs are for:
²CCD bus (+) circuits
²CCD bus (-) circuits
²CKP and APPS outputs to the PCM
²Data link connection for DRB scan tool
²Five volt sensor supply
²Fuel transfer (lift) pump
²Intake manifold air heater relays #1 and #2 con-
trol circuits
²Malfunction indicator lamp (Check engine lamp)
(databus)
²Oil Pressure Swith/warning lamp (databus)
²Fuel Control Actuator
²Wait-to-start warning lamp (databus)
²Fan Clutch PWM
²Water-In-Fuel (WIF) warning lamp (databus)
REMOVAL
The Engine Control Module (ECM) is bolted to a
support bracket near the fuel filter. The support
bracket mounts to the block with four capscrews and
vibration isolators. A ground wire is fastened to the
bracket. The other end of the wire is fastened to the
engine block.
(1) Record any Diagnostic Trouble Codes (DTC's)
found in the ECM.
Fig. 2 DIESEL ECM
1 - ENGINE CONTROL MODULE (ECM)
2 - ECM MOUNTING BOLT
3 - 50-WAY CONNECTOR
4 - SUPPORT PLATE
5 - 60-WAY CONNECTOR
8E - 4 ELECTRONIC CONTROL MODULESDR

POWERTRAIN CONTROL
MODULE
DESCRIPTION
DESCRIPTION - PCM
The Powertrain Control Module (PCM) is located
in the right-rear section of the engine compartment
under the cowl (Fig. 5).
Two different PCM's are used (JTEC and
NGC). These can be easily identified. JTEC's
use three 32±way connectors, NGC's use four
38±way connectors
DESCRIPTION - MODES OF OPERATION
As input signals to the Powertrain Control Module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT).
The PCM will operate in two different modes:
Open Loop and Closed Loop.
During Open Loop modes, the PCM receives input
signals and responds only according to preset PCM
programming. Input from the oxygen (O2S) sensors
is not monitored during Open Loop modes.During Closed Loop modes, the PCM will monitor
the oxygen (O2S) sensors input. This input indicates
to the PCM whether or not the calculated injector
pulse width results in the ideal air-fuel ratio. This
ratio is 14.7 parts air-to-1 part fuel. By monitoring
the exhaust oxygen content through the O2S sensor,
the PCM can fine tune the injector pulse width. This
is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
²Ignition switch ON
²Engine start-up (crank)
²Engine warm-up
²Idle
²Cruise
²Acceleration
²Deceleration
²Wide open throttle (WOT)
²Ignition switch OFF
The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle
and cruise modes, (with the engine at operating tem-
perature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following
actions occur:
²The PCM pre-positions the idle air control (IAC)
motor.
²The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic fuel
strategy.
²The PCM monitors the engine coolant tempera-
ture sensor input. The PCM modifies fuel strategy
based on this input.
²Intake manifold air temperature sensor input is
monitored.
²Throttle position sensor (TPS) is monitored.
²The auto shutdown (ASD) relay is energized by
the PCM for approximately three seconds.
²The fuel pump is energized through the fuel
pump relay by the PCM. The fuel pump will operate
for approximately three seconds unless the engine is
operating or the starter motor is engaged.
²The O2S sensor heater element is energized via
the ASD or O2S heater relay. The O2S sensor input
is not used by the PCM to calibrate air-fuel ratio dur-
ing this mode of operation.
ENGINE START-UP MODE
This is an Open Loop mode. The following actions
occur when the starter motor is engaged.
The PCM receives inputs from:
Fig. 5 POWERTRAIN CONTROL MODULE (PCM)
LOCATION
1 - COWL GRILL
2 - PCM
3 - COWL (RIGHT-REAR)
8E - 8 ELECTRONIC CONTROL MODULESDR

²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal
The PCM monitors the crankshaft position sensor.
If the PCM does not receive a crankshaft position
sensor signal within 3 seconds of cranking the
engine, it will shut down the fuel injection system.
The fuel pump is activated by the PCM through
the fuel pump relay.
Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
the injection sequence and injector pulse width by
turning the ground circuit to each individual injector
on and off.
The PCM determines the proper ignition timing
according to input received from the crankshaft posi-
tion sensor.
ENGINE WARM-UP MODE
This is an Open Loop mode. During engine warm-
up, the PCM receives inputs from:
²Battery voltage
²Crankshaft position sensor
²Engine coolant temperature sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
Based on these inputs the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
the injection sequence and injector pulse width by
turning the ground circuit to each individual injector
on and off.
²The PCM adjusts engine idle speed through the
idle air control (IAC) motor and adjusts ignition tim-
ing.
²The PCM operates the A/C compressor clutch
through the A/C compressor clutch relay. This is done
if A/C has been selected by the vehicle operator and
specified pressures are met at the high and low±pres-
sure A/C switches. Refer to Heating and Air Condi-
tioning for additional information.
²When engine has reached operating tempera-
ture, the PCM will begin monitoring O2S sensor
input. The system will then leave the warm-up mode
and go into closed loop operation.IDLE MODE
When the engine is at operating temperature, this
is a Closed Loop mode. At idle speed, the PCM
receives inputs from:
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Crankshaft position sensor
²Engine coolant temperature sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal
²Battery voltage
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Oxygen sensors
Based on these inputs, the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
injection sequence and injector pulse width by turn-
ing the ground circuit to each individual injector on
and off.
²The PCM monitors the O2S sensor input and
adjusts air-fuel ratio by varying injector pulse width.
It also adjusts engine idle speed through the idle air
control (IAC) motor.
²The PCM adjusts ignition timing by increasing
and decreasing spark advance.
²The PCM operates the A/C compressor clutch
through the A/C compressor clutch relay. This is done
if A/C has been selected by the vehicle operator and
specified pressures are met at the high and low±pres-
sure A/C switches. Refer to Heating and Air Condi-
tioning for additional information.
CRUISE MODE
When the engine is at operating temperature, this
is a Closed Loop mode. At cruising speed, the PCM
receives inputs from:
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Oxygen (O2S) sensors
Based on these inputs, the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then adjust
DRELECTRONIC CONTROL MODULES 8E - 9
POWERTRAIN CONTROL MODULE (Continued)

the injector pulse width by turning the ground circuit
to each individual injector on and off.
²The PCM monitors the O2S sensor input and
adjusts air-fuel ratio. It also adjusts engine idle
speed through the idle air control (IAC) motor.
²The PCM adjusts ignition timing by turning the
ground path to the coil(s) on and off.
²The PCM operates the A/C compressor clutch
through the clutch relay. This happens if A/C has
been selected by the vehicle operator and requested
by the A/C thermostat.
ACCELERATION MODE
This is an Open Loop mode. The PCM recognizes
an abrupt increase in throttle position or MAP pres-
sure as a demand for increased engine output and
vehicle acceleration. The PCM increases injector
pulse width in response to increased throttle opening.
DECELERATION MODE
When the engine is at operating temperature, this
is an Open Loop mode. During hard deceleration, the
PCM receives the following inputs.
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Vehicle speed
If the vehicle is under hard deceleration with the
proper rpm and closed throttle conditions, the PCM
will ignore the oxygen sensor input signal. The PCM
will enter a fuel cut-off strategy in which it will not
supply a ground to the injectors. If a hard decelera-
tion does not exist, the PCM will determine the
proper injector pulse width and continue injection.
Based on the above inputs, the PCM will adjust
engine idle speed through the idle air control (IAC)
motor.
The PCM adjusts ignition timing by turning the
ground path to the coil on and off.
WIDE OPEN THROTTLE MODE
This is an Open Loop mode. During wide open
throttle operation, the PCM receives the following
inputs.
²Battery voltage
²Crankshaft position sensor
²Engine coolant temperature sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor²Throttle position sensor (TPS)
²Camshaft position sensor signal
During wide open throttle conditions, the following
occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
the injection sequence and injector pulse width by
turning the ground circuit to each individual injector
on and off. The PCM ignores the oxygen sensor input
signal and provides a predetermined amount of addi-
tional fuel. This is done by adjusting injector pulse
width.
²The PCM adjusts ignition timing by turning the
ground path to the coil(s) on and off.
IGNITION SWITCH OFF MODE
When ignition switch is turned to OFF position,
the PCM stops operating the injectors, ignition coil,
ASD relay and fuel pump relay.
DESCRIPTION - 5 VOLT SUPPLIES
Two different Powertrain Control Module (PCM)
five volt supply circuits are used; primary and sec-
ondary.
DESCRIPTION - IGNITION CIRCUIT SENSE
This circuit ties the ignition switch to the Power-
train Control Module (PCM).
DESCRIPTION - POWER GROUNDS
The Powertrain Control Module (PCM) has 2 main
grounds. Both of these grounds are referred to as
power grounds. All of the high-current, noisy, electri-
cal devices are connected to these grounds as well as
all of the sensor returns. The sensor return comes
into the sensor return circuit, passes through noise
suppression, and is then connected to the power
ground.
The power ground is used to control ground cir-
cuits for the following PCM loads:
²Generator field winding
²Fuel injectors
²Ignition coil(s)
²Certain relays/solenoids
²Certain sensors
DESCRIPTION - SENSOR RETURN
The Sensor Return circuits are internal to the Pow-
ertrain Control Module (PCM).
Sensor Return provides a low±noise ground refer-
ence for all engine control system sensors. Refer to
Power Grounds for more information.
8E - 10 ELECTRONIC CONTROL MODULESDR
POWERTRAIN CONTROL MODULE (Continued)

OPERATION
OPERATION - PCM
The PCM operates the fuel system. The PCM is a
pre-programmed, triple microprocessor digital com-
puter. It regulates ignition timing, air-fuel ratio,
emission control devices, charging system, certain
transmission features, speed control, air conditioning
compressor clutch engagement and idle speed. The
PCM can adapt its programming to meet changing
operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to as Powertrain Control Module
(PCM) Outputs. The sensors and switches that pro-
vide inputs to the PCM are considered Powertrain
Control Module (PCM) Inputs.
The PCM adjusts ignition timing based upon
inputs it receives from sensors that react to: engine
rpm, manifold absolute pressure, engine coolant tem-
perature, throttle position, transmission gear selec-
tion (automatic transmission), vehicle speed, power
steering pump pressure, and the brake switch.
The PCM adjusts idle speed based on inputs it
receives from sensors that react to: throttle position,
vehicle speed, transmission gear selection, engine
coolant temperature and from inputs it receives from
the air conditioning clutch switch and brake switch.
Based on inputs that it receives, the PCM adjusts
ignition coil dwell. The PCM also adjusts the gener-
ator charge rate through control of the generator
field and provides speed control operation.
NOTE: PCM Inputs:
²ABS module (if equipped)
²A/C request (if equipped with factory A/C)
²A/C select (if equipped with factory A/C)
²A/C pressure transducer
²Auto shutdown (ASD) sense
²Battery temperature sensor
²Battery voltage
²Brake switch
²J1850 bus (+) circuits
²J1850 bus (-) circuits
²Camshaft position sensor signal
²Crankshaft position sensor
²Data link connection for DRB scan tool
²EATX module (if equipped)
²Engine coolant temperature sensor
²Fuel level (through J1850 circuitry)
²Generator (battery voltage) output
²Ignition circuit sense (ignition switch in on/off/
crank/run position)²Intake manifold air temperature sensor
²Knock sensors (2 on 3.7L engine)
²Leak detection pump (switch) sense (if equipped)
²Manifold absolute pressure (MAP) sensor
²Oil pressure
²Oxygen sensors
²Park/neutral switch (auto. trans. only)
²Power ground
²Power steering pressure switch (if equipped)
²Sensor return
²Signal ground
²Speed control multiplexed single wire input
²Throttle position sensor
²Transfer case switch (4WD range position)
²Vehicle speed signal
NOTE: PCM Outputs:
²A/C clutch relay
²Auto shutdown (ASD) relay
²J1850 bus (+/-) circuits for: speedometer, voltme-
ter, fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRB scan tool
²EGR valve control solenoid (if equipped)
²EVAP canister purge solenoid
²Five volt sensor supply (primary)
²Five volt sensor supply (secondary)
²Fuel injectors
²Fuel pump relay
²Generator field driver (-)
²Generator field driver (+)
²Idle air control (IAC) motor
²Ignition coil(s)
²Leak detection pump (if equipped)
²Malfunction indicator lamp (Check engine lamp).
Driven through J1850 circuits.
²Oxygen sensor heater relays
²Oxygen sensors (pulse width modulated)
²Radiator cooling fan relay (pulse width modu-
lated)
²Speed control vacuum solenoid
²Speed control vent solenoid
²Tachometer (if equipped). Driven through J1850
circuits.
²Transmission convertor clutch circuit. Driven
through J1850 circuits.
OPERATION - 5 VOLT SUPPLIES
Primary 5±volt supply:
²supplies the required 5 volt power source to the
Crankshaft Position (CKP) sensor.
²supplies the required 5 volt power source to the
Camshaft Position (CMP) sensor.
²supplies a reference voltage for the Manifold
Absolute Pressure (MAP) sensor.
DRELECTRONIC CONTROL MODULES 8E - 11
POWERTRAIN CONTROL MODULE (Continued)

SHIFT ATTEMPT LIMIT
To protect the transfer case system, the TCCM will
impose a limit on the number of shifts that can occur
over a calibrated time period. The system will monitor
the number of 'D' channel segment transitions that
occur in any 30 second time period. If the number of
segment transitions is 30 or greater, the system will go
into a default mode. The default mode of operation for
shifting is that the number of allowed 'D' channel tran-
sitions permitted to occur will be 3 over each 15 second
 100 msec calibrated window of time. After 5 minutes
 100 msec, the motor can be assumed to have cooled
down and the system will revert to normal operation.
The following rules also apply to the shift limit:
²The attempt limit will not prevent shifts coming
out of NEUTRAL, they will be allowed regardless of
the counter/timer.
²Any shift that is in progress when the counter
reaches a maximum count in time will be allowed to
complete before the default mode is entered. D-chan-
nel transitions during this period will not be counted
towards the default mode limit.
²A block, regardless of the direction, whether
towards destination or back towards reversal target
(shift timer expiring), will count as a value of 2 tran-
sitions towards the 30 segment transitions to go into
default mode as defined above. Current attempt limit
values are 30 transitions in 30 seconds and default
mode values are 3 transitions every 15 seconds for 5
minutes.
TRANSMISSION CONTROL
MODULE
DESCRIPTION
The Transmission Control Module (TCM) (Fig. 10)
may be sub-module within the Powertrain Control
Module (PCM) or a standalone module, depending on
the vehicle engine. The PCM, and TCM when
equipped, is located at the right rear of the engine
compartment, near the right inner fender.
OPERATION
The Transmission Control Module (TCM) controls
all electronic operations of the transmission. The
TCM receives information regarding vehicle opera-
tion from both direct and indirect inputs, and selects
the operational mode of the transmission. Direct
inputs are hardwired to, and used specifically by the
TCM. Indirect inputs are shared with the TCM via
the vehicle communication bus.
Some examples ofdirect inputsto the TCM are:
²Battery (B+) voltage
²Ignition ªONº voltage
²Transmission Control Relay (Switched B+)²Throttle Position Sensor
²Crankshaft Position Sensor
²Transmission Range Sensor
²Pressure Switches
²Transmission Temperature Sensor
²Input Shaft Speed Sensor
²Output Shaft Speed Sensor
²Line Pressure Sensor
Some examples ofindirect inputsto the TCM are:
²Engine/Body Identification
²Manifold Pressure
²Target Idle
²Torque Reduction Confirmation
²Engine Coolant Temperature
²Ambient/Battery Temperature
²DRBIIItScan Tool Communication
Based on the information received from these var-
ious inputs, the TCM determines the appropriate
shift schedule and shift points, depending on the
present operating conditions and driver demand.
This is possible through the control of various direct
and indirect outputs.
Some examples of TCMdirect outputsare:
²Transmission Control Relay
²Solenoids
²Torque Reduction Request
Some examples of TCMindirect outputsare:
²Transmission Temperature (to PCM)
²PRNDL Position (to BCM)
In addition to monitoring inputs and controlling
outputs, the TCM has other important responsibili-
ties and functions:
²Storing and maintaining Clutch Volume Indexes
(CVI)
²
Storing and selecting appropriate Shift Schedules
²System self-diagnostics
²Diagnostic capabilities (with DRBIIItscan tool)
Fig. 10 PCM/TCM Location
1 - RIGHT FENDER
2 - TRANSMISSION CONTROL MODULE
3 - POWERTRAIN CONTROL MODULE
DRELECTRONIC CONTROL MODULES 8E - 19
TRANSFER CASE CONTROL MODULE (Continued)

Schedule Condition Expected Operation
Extreme ColdOil temperature below -16É F -Park, Reverse, Neutral and 1st and
3rd gear only in D position, 2nd
gear only in Manual 2 or L
-No EMCC
Super ColdOil temperature between -12É F and
10É F- Delayed 2-3 upshift
- Delayed 3-4 upshift
- Early 4-3 coastdown shift
- High speed 4-2, 3-2, 2-1 kickdown
shifts are prevented
-Shifts at high throttle openings willl
be early.
- No EMCC
ColdOil temperature between 10É F and
36É F-Shift schedule is the same as
Super Cold except that the 2-3
upshifts are not delayed.
WarmOil temperature between 40É F and
80É F- Normal operation (upshift,
kickdowns, and coastdowns)
- No EMCC
HotOil temperature between 80É F and
240É F- Normal operation (upshift,
kickdowns, and coastdowns)
- Normal EMCC operation
OverheatOil temperature above 240É F or
engine coolant temperature above
244É F- Delayed 2-3 upshift
- Delayed 3-4 upshift
- 3rd gear FEMCC from 30-48 mph
- 3rd gear PEMCC above 35 mph
- Above 25 mph the torque
converter will not unlock unless the
throttle is closed or if a wide open
throttle 2nd PEMCC to 1 kickdown
is made
STANDARD PROCEDURE
STANDARD PROCEDURE - TCM QUICK LEARN
The quick learn procedure requires the use of the
DRBtscan tool.
This program allows the electronic transmission
system to recalibrate itself. This will provide the
proper transmission operation. The quick learn pro-
cedure should be performed if any of the following
procedures are performed:
²Transmission Assembly Replacement
²Transmission Control Module Replacement
²Solenoid Pack Replacement
²Clutch Plate and/or Seal Replacement
²Valve Body Replacement or Recondition
To perform the Quick Learn Procedure, the follow-
ing conditions must be met:
²The brakes must be applied
²The engine speed must be above 500 rpm
²The throttle angle (TPS) must be less than 3
degrees²The shift lever position must stay in PARK until
prompted to shift to overdrive
²The shift lever position must stay in overdrive
after the Shift to Overdrive prompt until the DRBt
indicates the procedure is complete
²The calculated oil temperature must be above
60É and below 200É
STANDARD PROCEDURE - DRIVE LEARN
When a transmission is repaired and a Quick
Learn procedure has been performed on the Trans-
mission Control Module (TCM), the following Drive
Learn procedure can be performed to fine tune any
shifts which are particularly objectionable.
NOTE: It is not necessary to perform the complete
Drive Learn procedure every time the TCM is Quick
Learned. Perform only the portions which target the
objectionable shift.
DRELECTRONIC CONTROL MODULES 8E - 21
TRANSMISSION CONTROL MODULE (Continued)