
CLUTCH VOLUME INDEX (CVI)
An important function of the TCM is to monitor
Clutch Volume Index (CVI). CVIs represent the vol-
ume of fluid needed to compress a clutch pack.
The TCM monitors gear ratio changes by monitor-
ing the Input and Output Speed Sensors. The Input,
or Turbine Speed Sensor sends an electrical signal to
the TCM that represents input shaft rpm. The Out-
put Speed Sensor provides the TCM with output
shaft speed information.
By comparing the two inputs, the TCM can deter-
mine transaxle gear ratio. This is important to the
CVI calculation because the TCM determines CVIs
by monitoring how long it takes for a gear change to
occur (Fig. 15).
Gear ratios can be determined by using the DRB
Scan Tool and reading the Input/Output Speed Sen-
sor values in the ªMonitorsº display. Gear ratio can
be obtained by dividing the Input Speed Sensor value
by the Output Speed Sensor value.
For example, if the input shaft is rotating at 1000
rpm and the output shaft is rotating at 500 rpm,
then the TCM can determine that the gear ratio is
2:1. In direct drive (3rd gear), the gear ratio changes
to 1:1. The gear ratio changes as clutches are applied
and released. By monitoring the length of time it
takes for the gear ratio to change following a shift
request, the TCM can determine the volume of fluid
used to apply or release a friction element.
The volume of transmission fluid needed to apply
the friction elements are continuously updated for
adaptive controls. As friction material wears, the vol-
ume of fluid need to apply the element increases.
Certain mechanical problems within the clutch
assemblies (broken return springs, out of position
snap rings, excessive clutch pack clearance, improper
assembly, etc.) can cause inadequate or out-of-rangeclutch volumes. Also, defective Input/Output Speed
Sensors and wiring can cause these conditions. The
following chart identifies the appropriate clutch vol-
umes and when they are monitored/updated:
CLUTCH VOLUMES
ClutchWhen Updated
Proper Clutch
Volume
Shift Sequence Oil Temperature Throttle Angle
L/R2-1 or 3-1 coast
downshift>70É <5É 35to83
2/4 1-2 shift
> 110É5 - 54É20 to 77
OD 2-3 shift 48 to 150
UD 4-3 or 4-2 shift > 5É 24 to 70
Fig. 15 Example of CVI Calculation
1 - OUTPUT SPEED SENSOR
2 - OUTPUT SHAFT
3 - CLUTCH PACK
4 - SEPARATOR PLATE
5 - FRICTION DISCS
6 - INPUT SHAFT
7 - INPUT SPEED SENSOR
8 - PISTON AND SEAL
RSELECTRONIC CONTROL MODULES8E-29
TRANSMISSION CONTROL MODULE (Continued)
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ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
ENGINE CONTROL MODULE
DESCRIPTION..........................1
OPERATION............................1
STANDARD PROCEDURE - PCM/ECM/SKIM
PROGRAMMING - DIESEL...............2REMOVAL.............................4
INSTALLATION..........................4
ENGINE CONTROL MODULE
DESCRIPTION
The ECM is located in the left front corner of the
engine compartment attached to the radiator support
(Fig. 1).
OPERATION
The ECM has been programmed to monitor differ-
ent circuits of the diesel fuel injection system. Thismonitoring is called on-board diagnostics. Certain cri-
teria must be met for a diagnostic trouble code to be
entered into the ECM memory. The criteria may be a
range of: engine rpm, engine temperature, time or
other input signals to the ECM. If all of the criteria
for monitoring a system or circuit are met, and a
problem is sensed, then a DTC will be stored in the
ECM memory. It is possible that a DTC for a moni-
tored circuit may not be entered into the ECM mem-
ory, even though a malfunction has occurred. This
may happen when the monitoring criteria have not
been met. The ECM compares input signal voltages
from each input device with specifications (the estab-
lished high and low limits of the input range) that
are programmed into it for that device. If the input
voltage is not within the specifications and other
trouble code criteria are met, a DTC will be stored in
the ECM memory.
ECM OPERATING MODES
As input signals to the ECM change, the ECM
adjusts its response to the output devices. For exam-
ple, the ECM must calculate a different fuel quantity
and fuel timing for engine idle condition than it
would for a wide open throttle condition. There are
several different modes of operation that determine
how the ECM responds to the various input signals.
Ignition Switch On (Engine Off)
When the ignition is turned on, the ECM activates
the glow plug relay for a time period that is deter-
mined by engine coolant temperature, atmospheric
temperature and battery voltage.
Engine Start-Up Mode
The ECM uses the engine temperature sensor and
the crankshaft position sensor (engine speed) inputs
to determine fuel injection quantity.
Normal Driving Modes
Engine idle, warm-up, acceleration, deceleration
and wide open throttle modes are controlled based on
all of the sensor inputs to the ECM. The ECM uses
Fig. 1 ENGINE CONTROL MODULE LOCATION-
TYPICAL
1 - BATTERY
2 - IPM (INTEGRATED POWER MODULE)
3 - ECM (ENGINE CONTROL MODULE)
4 - RETAINING BOLT
5 - RADIATOR SUPPORT
6 - CLUTCH CABLE BRACKET (LHD)
7 - CLUTCH CABLE BRACKET RETAINING BOLT (LHD)
RGELECTRONIC CONTROL MODULES8Ea-1
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OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY
CONDITION POSSIBLE CAUSES CORRECTION
Does not drive generator
(Generator not Charging)Clutch failure Replace Decoupler
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Raise vehicle and support.
(4) Remove the right front lower splash shield.
(5) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures (Fig. 5).
(6) Lower vehicle.
(7) Remove the Air Box, refer to the Engine section
for more information.
(8) Use Special Tool #8433 (Fig. 7) to loosen the
Generator Decoupler (Fig. 6).
(9) Remove the tool.
(10) Remove the Generator Decoupler.
INSTALLATION
(1) Install the Generator Decoupler to the genera-
tor shaft.
(2) Use Special Tool #8433 (Fig. 7) to tighten the
Generator Decoupler (Fig. 8). Refer to the torque
chart for the proper torque.
Fig. 4 GENERATOR DECOUPLER 3.3/3.8L
Fig. 5 DRIVE BELT 3.3/3.8L
8F - 26 CHARGINGRS
GENERATOR DECOUPLER PULLEY (Continued)
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(5) Connect the push-in field wire connector to
back of generator.
(6) Install the EVAP Purge solenoid to its bracket.
(7) Install the Air Box, refer to the Engine/Air
Cleaner for more information.
(8) Connect the Inlet Air Temperature sensor.
(9) Connect battery negative cable.
INSTALLATION - 2.5L
(1) Install generator.
(2) Install the 2 lower mounting Bolts (Fig. 8).
(3) Install the Air Cleaner Box (Fig. 7).
(4) Install the upper support bracket (Fig. 6).
(5) Install the wiring harness on upper generator
bracket (Fig. 6).
(6) Connect the field connection (Fig. 5).
(7) Connect the generator battery connection (Fig.
5).
(8) Raise vehicle and support.
(9) Install the generator drive belt (Fig. 4).
(10) Install the right front splash shield (Fig. 3).
(11) Lower vehicle.
(12) Install the engine cover (Fig. 2).
(13) Connect the negative battery cable (Fig. 1).
INSTALLATION - 3.3/3.8L
(1) Roll and place generator in position on vehicle
(Fig. 10).
(2) Install upper bolts to hold generator in place.
(3) Lubricate the o-ring. Install oil dip stick tube.
(4) Install the upper oil dip stick tube bolt.
(5) Place B+ terminal in position on generator.
(6) Install nut to hold B+ wire terminal to back of
generator.
(7) Connect the push-in field wire connector into
back of generator.
(8) Raise vehicle and support.
(9) Install the lower mounting bolt and tighten.
(10) Install the lower oil dip stick tube bolt and
tighten (Fig. 9).
(11) Install accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(12) Install the right front lower splash shield.
(13) Lower vehicle.
(14) Install wiring harness to the oil dip stick tube
(15) Connect battery negative cable.
(16) Verify generator output rate.
INSTALLATION - 3.5L
(1) Install generator (Fig. 16) and the 3 mounting
bolts and tighten.
(2) Connect the generator positive battery cable
(Fig. 15).
(3) Connect the field connector and lock the con-
nector (Fig. 15).
(4) Install the axle shaft to the transmission.(5) Install axle to steering knuckle (Fig. 13).
(6) Install the 2 upper clevies bolts and tighten,
refer to the Suspension section.
(7) Install axle nut and tighten, refer to the Differ-
ential and Driveline section.
(8) Relocate the ABS sensor wiring to bracket (Fig.
12).
(9) Install the accessory drive belt (Fig. 14), refer
to the Cooling section.
(10) Install the right front splash shield.
(11) Install the right front tire, refer to the Wheels
and Tires section.
(12) Lower vehicle.
(13) Connect the negative battery cable.
GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
17). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
Fig. 17 GENERATOR DECOUPLER 3.3/3.8L
8Fa - 28 CHARGINGRG
GENERATOR (Continued)
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INSTALLATION
(1) Install the Generator Decoupler to the genera-
tor shaft.
(2) Use Special Tool #8433 (Fig. 20) to tighten the
Generator Decoupler (Fig. 21). Refer to the torque
chart for the proper torque.
(3) Install the Air Box, refer to the Engine section
for more information.
(4) Raise vehicle and support.
(5) Install accessory drive belt, refer to the Cooling
System section for proper procedures (Fig. 18).
(6) Install the right front lower splash shield.
(7) Lower vehicle.
(8) Connect battery negative cable.
VOLTAGE REGULATOR
DESCRIPTION
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
OPERATION
The amount of DC current produced by the gener-
ator is controlled by EVR circuitry contained within
the PCM. This circuitry is connected in series with
the generators second rotor field terminal and its
ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage (B+) and
calculated battery temperature or inlet air tempera-
ture sensor (refer to Inlet Air Temperature Sensor, if
equipped, for more information ). It then determines
a target charging voltage. If sensed battery voltage is
lower than the target voltage, the PCM grounds the
field winding until sensed battery voltage is at the
target voltage. A circuit in the PCM cycles the
ground side of the generator field at 250 times per
second (250Hz), but has the capability to ground the
field control wire 100% of the time (full field) to
achieve the target voltage. If the charging rate can-
not be monitored (limp-in), a duty cycle of 25% is
used by the PCM in order to have some generator
output. Also refer to Charging System Operation for
additional information.
Fig. 21 DECOUPLER INSTALLATION (Litens)
8Fa - 30 CHARGINGRG
GENERATOR DECOUPLER PULLEY (Continued)
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IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM..........1
OPERATION - IGNITION SYSTEM...........1
SPECIFICATIONS
TORQUE.............................2
SPARK PLUG CABLE RESISTANCE........2
SPARK PLUG.........................2
FIRING ORDER........................3
AUTO SHUT DOWN RELAY
DESCRIPTION..........................3
OPERATION............................3
CAMSHAFT POSITION SENSOR
DESCRIPTION..........................3
OPERATION............................4
REMOVAL
REMOVAL - 2.4L.......................4
REMOVAL - 3.3/3.8L....................4
INSTALLATION
INSTALLATION - 2.4L...................6
INSTALLATION - 3.3/3.8L.................6
IGNITION COIL
DESCRIPTION..........................6
OPERATION............................6
REMOVAL
REMOVAL - 2.4L.......................7REMOVAL - 3.3/3.8L....................7
INSTALLATION
INSTALLATION - 2.4L...................7
INSTALLATION - 3.3/3.8L.................8
KNOCK SENSOR
DESCRIPTION..........................8
OPERATION............................8
REMOVAL
REMOVAL - 2.4L.......................8
REMOVAL - 3.8L.......................8
INSTALLATION
INSTALLATION - 2.4L...................8
INSTALLATION - 3.8L...................8
SPARK PLUG
DESCRIPTION
DESCRIPTION - STANDARD 4 CYLINDER . . . 9
DESCRIPTION - PLATINUM PLUGS........9
REMOVAL.............................9
INSTALLATION.........................10
SPARK PLUG CABLE
DESCRIPTION.........................10
REMOVAL.............................10
INSTALLATION.........................10
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM
NOTE: All engines use a fixed ignition timing sys-
tem. Basic ignition timing is not adjustable. All
spark advance is determined by the Powertrain
Control Module (PCM).
The distributorless ignition system used on these
engines is referred to as the Direct Ignition System
(DIS). The system's three main components are the
coils, crankshaft position sensor, and camshaft posi-
tion sensor. The coil on plug ignition system utilizesan ignition coil for every cylinder, it is mounted
directly over the each spark plug.
OPERATION - IGNITION SYSTEM
The crankshaft position sensor and camshaft posi-
tion sensor are hall effect devices. The camshaft posi-
tion sensor and crankshaft position sensor generate
pulses that are inputs to the PCM. The PCM deter-
mines engine position from these sensors. The PCM
calculates injector sequence and ignition timing from
crankshaft & camshaft position. For a description of
both sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor.
RSIGNITION CONTROL8I-1
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SPECIFICATIONS
TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
2.4L Target Magnet Screw 3 30
2.4L Camshaft Sensor
Screw12.9 115
3.3/3.8L Camshaft Sensor
Screw14.1 125
2.4L Ignition coil bolts 11.8 105
3.3/3.8LIgnition coil bolts 11.8 105
Spark Plugs 17.5 13
Knock Sensor 10 7
SPARK PLUG CABLE RESISTANCE
2.4L
CABLE Maximum Resistance
1, 2, 3, & 4 10.8K ohms
3.3/3.8L
CABLE Maximum Resistance
#1 22.5K ohms
#2 22.8K ohms
#3 19.3K ohms
#4 19.3K ohms
#5 13.6K ohms
#6 16.4K ohms
SPARK PLUG
Engine Spark Plug Gap Thread Size
2.4L RE14MCC5 0.048 TO 0.053 14mm (1 in.) reach
Engine Spark Plug Gap Thread Size
3.3L RE14PLP5 0.048 TO 0.053 14mm (1 in.) reach
3.8L RE14PLP5 0.048 TO 0.053 14mm (1 in. ) reach
8I - 2 IGNITION CONTROLRS
IGNITION CONTROL (Continued)
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FIRING ORDERAUTO SHUT DOWN RELAY
DESCRIPTION
The relay is located in the Power Distribution Cen-
ter (PDC). For the location of the relay within the
PDC, refer to the PDC cover for location. Check elec-
trical terminals for corrosion and repair as necessary
OPERATION
The ASD sense circuit informs the PCM when the
ASD relay energizes. A 12 volt signal at this input
indicates to the PCM that the ASD has been acti-
vated. This input is used only to sense that the ASD
relay is energized.
When energized, the ASD relay supplies battery
voltage to the fuel injectors, ignition coils and the
heating element in each oxygen sensor.
When energized, the ASD relay provides power to
operate the injectors, ignition coil, generator field, O2
sensor heaters (both upstream and downstream),
(EGR solenoid and PCV heater if equipped) and also
provides a sense circuit to the PCM for diagnostic
purposes. If the PCM does not receive 12 volts from
this input after grounding the ASD relay, it sets a
Diagnostic Trouble Code (DTC). The PCM energizes
the ASD any time there is a Crankshaft Position sen-
sor signal that exceeds a predetermined value. The
ASD relay can also be energized after the engine has
been turned off to perform an O2 sensor heater test,
if vehicle is equipped with OBD II diagnostics.
As mentioned earlier, the PCM energizes the ASD
relay during an O2 sensor heater test. This test is
performed only after the engine has been shut off.
The PCM still operates internally to perform several
checks, including monitoring the O2 sensor heaters.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
The camshaft position sensorfor the 3.3/3.8L is
mounted in the front of the timing case cover (Fig. 6)
and the camshaft position sensor for the 2.4L is
mounted on the end of the cylinder head (Fig. 3).
FIRING ORDER 2.4L
Firing Order 1-2-3-4-5-6 3.3/3.8L
1 - Electrical Connector
RSIGNITION CONTROL8I-3
IGNITION CONTROL (Continued)
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