2002 DODGE RAM service

²Head/Park Lights-On Warning- The CTM
chime tone generator will generate repetitive chime
tones at a fast rate to announce that hard wired
inputs from the driver door ajar switch, headlamp
switch, and ignition switch indicate that the exterior
lamps are turned On with the driver side front door
opened and the ignition switch in the Off position.
The chimes will continue to sound until the exterior
lamps are turned Off, the driver side front door is
closed, or the ignition switch is turned to the On
position, whichever occurs first.
²Key-In-Ignition Warning- The CTM chime
tone generator will generate repetitive chime tones at
a fast rate to announce that hard wired inputs from
the driver door ajar switch, headlamp switch, and
ignition switch indicate that the key is in the ignition
lock cylinder with the driver side front door opened
and the ignition switch in the Off position. The
chimes will continue to sound until the key is
removed from the ignition lock cylinder, the driver
side front door is closed, or the ignition switch is
turned to the On position, whichever occurs first.
²Warning Chime Support- The CTM chime
tone generator will generate repetitive chime tones at
a slow rate to announce that a hard wired chime
request input has been received from the EMIC.
These chime tones provide an audible alert to the
vehicle operator that supplements certain visual indi-
cations displayed by the EMIC. Supplemented indica-
tions include the following:
²The ªAirbagº indicator is illuminated. The
chimes will continue to sound for a duration of about
four seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªCheck Gagesº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªLow Fuelº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªLow Washº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªTrans Tempº indicator is illuminated (auto-
matic transmission only). The chimes will continue to
sound for a duration of about two seconds each time
the indicator is illuminated or until the ignition
switch is turned to the Off position, whichever occurs
first.²The vehicle is over a programmed speed value
(Middle East Gulf Coast Country (GCC) only). The
CTM chime tone generator will generate repetitive
chime tones at a slow rate to announce that the vehi-
cle speed exceeds a programmed value. The chimes
will continue to sound until the vehicle speed is
below the programmed value.
²The ªWater-In-Fuelº indicator is illuminated
(diesel engine only). The chimes will continue to
sound for a duration of about two seconds each time
the indicator is illuminated or until the ignition
switch is turned to the Off position, whichever occurs
first.
The CTM provides chime service for all available
features in the chime warning system. The CTM
relies upon hard wired inputs from the driver door
ajar switch, the EMIC, the headlamp switch, and the
key-in ignition switch (ignition switch) to provide
chime service for all of the chime warning system
features. Upon receiving the proper inputs, the CTM
activates the integral chime tone generator to pro-
vide the audible chime tone to the vehicle operator.
The chime tone generator in the CTM is capable of
producing repeated chime tones at two different
rates, slow or fast. The slow chime rate is about fifty
chime tones per minute, while the fast chime rate is
about 180 chime tones per minute. The internal pro-
gramming of the CTM and the EMIC determines the
priority of each chime tone request input that is
received, as well as the rate and duration of each
chime tone that is to be generated.
The hard wired chime warning system inputs to
the CTM and the EMIC, as well as other hard wired
circuits for this system may be diagnosed and tested
using conventional diagnostic tools and procedures.
See the owner's manual in the vehicle glove box for
more information on the features provided by the
chime warning system.
DIAGNOSIS AND TESTING - CHIME WARNING
SYSTEM
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and location views for the various wire har-
ness connectors, splices and grounds. The hard wired
chime warning system inputs to the Central Timer
Module (CTM) and the Electro-Mechanical Instru-
ment Cluster (EMIC), as well as other hard wired
circuits for this system may be diagnosed and tested
using conventional diagnostic tools and procedures.
8B - 2 CHIME/BUZZERBR/BE
CHIME WARNING SYSTEM (Continued)

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
CHIME WARNING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
SEAT BELT WARNING
CHIME WITH SEAT BELT
BUCKLED1. Seat belt switch sense
circuit shorted.1. Disconnect the body wire harness connector
for the seat belt switch and the instrument panel
wire harness connector (Connector C2) for the
EMIC. Check for continuity between the seat belt
switch sense circuit cavity and a good ground.
There should be no continuity. Repair the seat
belt switch sense circuit, if required.
2. Faulty seat belt switch. 2. Check for continuity between the ground circuit
cavity and the seat belt switch sense circuit cavity
of the seat belt switch connector receptacle.
There should be no continuity with the seat belt
buckled. Replace the faulty seat belt, if required.
NO SEAT BELT WARNING
CHIME WITH SEAT BELT
UNBUCKLED, BUT OTHER
CHIME FEATURES OK1. Seat belt switch ground
circuit open.1. Disconnect the body wire harness connector
for the seat belt switch. Check for continuity
between the ground circuit cavity of the connector
for the seat belt switch and a good ground. There
should be continuity. If not OK, repair the open
ground circuit to ground as required.
2. Seat belt switch sense
circuit open.2. With the body wire harness connector for the
seat belt switch and the instrument panel wire
harness connector (Connector C2) for the EMIC
disconnected, there should be continuity between
the seat belt switch sense circuit cavities of the
two connectors. Repair the seat belt switch sense
circuit, if required.
3. Faulty seat belt switch. 3. Check for continuity between the ground circuit
cavity and the seat belt switch sense circuit cavity
of the seat belt switch connector receptacle.
There should be continuity with the seat belt
unbuckled. Replace the faulty seat belt, if
required.
BR/BECHIME/BUZZER 8B - 3
CHIME WARNING SYSTEM (Continued)

The features that the CTM supports or controls
include the following:
²Automatic Door Lock- The high-line/premium
CTM provides an optional automatic door lock fea-
ture (also known as rolling door locks). This is a pro-
grammable feature.²Central Locking- The high-line/premium CTM
provides an optional central locking/unlocking fea-
ture.
²Chimes- All versions of the CTM provide chime
service through an integral chime tone generator.
²Courtesy Lamps- The high-line/premium CTM
provides courtesy lamp control with timed load shed-
ding.
²Door Lock Inhibit- The high-line/premium
CTM provides a door lock inhibit feature.
²Enhanced Accident Response- The high-line/
premium CTM provides an optional enhanced acci-
dent response feature. This is a programmable
feature.
²Heated Seats- The premium CTM controls the
optional heated seat system by controlling the opera-
tion of the heated seat relay.
²Illuminated Entry- The high-line/premium
CTM provides a timed illuminated entry feature.
²Intermittent Wipe Control- All versions of
the CTM provide control of the intermittent wipe
delay, and wipe-after-wash features.
²Panic Mode- The high-line/premium CTM pro-
vides support for the optional RKE system panic
mode features.
²Power Lock Control- The high-line/premium
CTM provides the optional power lock system fea-
tures, including support for the automatic door lock
and door lock inhibit modes.
²Programmable Features- The high-line/pre-
mium CTM provides support for certain programma-
ble features.
²Remote Keyless Entry- The high-line/pre-
mium CTM provides the optional Remote Keyless
Entry (RKE) system features, including support for
the RKE Lock (with optional horn chirp), Unlock,
Panic, and illuminated entry modes, as well as the
ability to be programmed to recognize up to four
RKE transmitters. The RKE horn chirp is a program-
mable feature.
²Remote Radio Switch Interface- The high-
line/premium CTM monitors and transmits the sta-
tus of the optional remote radio switches.
²Speed Sensitive Intermittent Wipe Control-
The high-line/premium CTM provides the speed sen-
sitive intermittent wipe feature.
²Vehicle Theft Alarm- The high-line/premium
CTM provides control of the optional Vehicle Theft
Alarm features, including support for the central
locking/unlocking mode.
Hard wired circuitry connects the CTM to the elec-
trical system of the vehicle. These hard wired circuits
are integral to several wire harnesses, which are
routed throughout the vehicle and retained by many
different methods. These circuits may be connected to
each other, to the vehicle electrical system and to the
Fig. 1 Central Timer Module (Base)
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTOR
4 - CENTRAL TIMER MODULE
Fig. 2 Central Timer Module (High-Line/Premium)
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTORS
4 - CENTRAL TIMER MODULE
8E - 2 ELECTRONIC CONTROL MODULESBR/BE
CENTRAL TIMER MODULE (Continued)

CTM through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
All versions of the CTM for this model are serviced
only as a complete unit. Many of the electronic fea-
tures in the vehicle controlled or supported by the
high-line or premium versions of the CTM are pro-
grammable using the DRBIIItscan tool.However, if
any of the CTM hardware components are damaged
or faulty, the entire CTM unit must be replaced. The
base version of the CTM and the hard wired inputs
or outputs of all CTM versions can be diagnosed
using conventional diagnostic tools and methods;
however, for diagnosis of the high-line or premium
versions of the CTM or the CCD data bus, the use of
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
OPERATION
The Central Timer Module (CTM) is designed to
control and integrate many of the electronic features
and functions of the vehicle. The base version of the
CTM monitors only hard wired inputs and responds
with the proper hard wired outputs. The microproces-
sor-based high-line/premium version of the CTM
monitors many hard wired switch and sensor inputs
as well as those resources it shares with other elec-
tronic modules in the vehicle through its communica-
tion over the Chrysler Collision Detection (CCD) data
bus network. The internal programming and all of
these inputs allow the high-line/premium CTM
microprocessor to determine the tasks it needs to
perform and their priorities, as well as both the stan-
dard and optional features that it should provide.
The high-line/premium CTM programming then per-
forms those tasks and provides those features
through both CCD data bus communication with
other electronic modules and through hard wired out-
puts to a number of circuits, relays, and actuators.
These outputs allow the high-line/premium CTM the
ability to control numerous accessory systems in the
vehicle.
All versions of the CTM operate on battery current
received through fuses in the Junction Block (JB) on
a non-switched fused B(+) circuit, a fused ignition
switch output (st-run) circuit (base version only), and
a fused ignition switch output (run-acc) circuit (high-
line/premium version only). This arrangement allows
the CTM to provide some features regardless of the
ignition switch position, while other features willoperate only with the ignition switch in the Acces-
sory, On, and/or Start positions. All versions of the
CTM are grounded through their connector and take
out of the instrument panel wire harness. The high-
line/premium CTM has another ground received
through a second connector and take out of the
instrument panel wire harness. The first ground cir-
cuit receives ground through a take out with an eye-
let terminal connector of the instrument panel wire
harness that is secured by a nut to a ground stud
located on the left instrument panel end bracket,
while the second ground circuit (high-line/premium
version only) receives ground through a take out with
an eyelet terminal connector of the instrument panel
wire harness that is secured by a nut to a ground
stud located on the back of the instrument panel
armature above the inboard side of the instrument
panel steering column opening.
The high-line/premium CTM monitors its own
internal circuitry as well as many of its input and
output circuits, and will store a Diagnostic Trouble
Code (DTC) in electronic memory for any failure it
detects. These DTCs can be retrieved and diagnosed
using a DRBIIItscan tool. Refer to the appropriate
diagnostic information.
HARD WIRED INPUTS
The hard wired inputs to the CTM include the fol-
lowing:
²CCD bus± - high-line/premium version only
²CCD bus+ - high-line/premium version only
²Cylinder lock switch mux - high-line premium
version only
²Driver door ajar switch sense
²Fused B(+)
²Fused ignition switch output (run-acc) - high-
line/premium version only
²Fused ignition switch output (st-run) - base ver-
sion only
²Ground (one circuit - base version, two circuits -
high-line/premium version)
²Key-in ignition switch sense
²Passenger door ajar switch sense - high-line/pre-
mium version only
²Power door lock motor B(+) lock - high-line/pre-
mium version only
²Power door lock motor B(+) unlock - high-line/
premium version only
²Radio control mux - high-line/premium version
only
²Tone request signal
²Washer switch sense
²Wiper park switch sense
²Wiper switch mode sense
²Wiper switch mode signal
BR/BEELECTRONIC CONTROL MODULES 8E - 3
CENTRAL TIMER MODULE (Continued)

HARD WIRED OUTPUTS
The hard wired outputs of the CTM include the fol-
lowing:
²CCD bus± - high-line/premium version only
²CCD bus+ - high-line/premium version only
²Courtesy lamp switch output - high-line/pre-
mium version only
²Door lock driver - high-line/premium version
only
²Door unlock driver - high-line/premium version
only
²Headlamp relay control - high-line/premium ver-
sion only
²Heated seat relay control - premium version
only
²Horn relay control - high-line/premium version
only
²VTSS indicator driver - high-line/premium ver-
sion only
²Wiper motor relay control
MESSAGING
The high-line/premium CTM uses the following
messages received from other electronic modules over
the CCD data bus:
²Airbag Deploy (ACM)
²Charging System Failure (PCM)
²Engine RPM (PCM)
²System Voltage (PCM)
²Vehicle Speed (PCM)
²Voltage Fault (PCM)
The high-line/premium CTM provides the following
messages to other electronic modules over the CCD
data bus:
²Engine Enable (PCM)
²Radio Seek Up (Radio)
²Radio Seek Down (Radio)
²Radio Volume Up (Radio)
²Radio Volume Down (Radio)
²Preset Scan (Radio)
DIAGNOSIS AND TESTING - CENTRAL TIMER
MODULE
The hard wired inputs to and outputs from the
Central Timer Module (CTM) may be diagnosed and
tested using conventional diagnostic tools and meth-
ods. Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and location views for the various wire har-
ness connectors, splices and grounds.
However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the high-line/pre-
mium CTM. In order to obtain conclusive testing of
the high-line/premium CTM, the Chrysler CollisionDetection (CCD) data bus network and all of the elec-
tronic modules that provide inputs to or receive out-
puts from the CTM must also be checked. The most
reliable, efficient, and accurate means to diagnose
the high-line/premium CTM, the CCD data bus net-
work, and the electronic modules that provide inputs
to or receive outputs from the high-line/premium
CTM requires the use of a DRBIIItscan tool and the
appropriate diagnostic information. The DRBIIIt
scan tool can provide confirmation that the CCD data
bus network is functional, that all of the electronic
modules are sending and receiving the proper mes-
sages over the CCD data bus, and that the CTM is
receiving the proper hard wired inputs and respond-
ing with the proper hard wired outputs needed to
perform its many functions.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: The following tests may not prove conclu-
sive in the diagnosis of the high-line or premium
versions of the Central Timer Module (CTM). The
most reliable, efficient, and accurate means to diag-
nose the high-line or premium CTM requires the
use of a DRBIIITscan tool and the appropriate diag-
nostic information.
(1) Check the fused B(+) fuse (Fuse 13 - 10
ampere) in the Junction Block (JB). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
(Fuse 13 - 10 ampere) in the JB. If OK, go to Step 3.
If not OK, repair the open fused B(+) circuit between
the JB and the Power Distribution Center (PDC) as
required.
(3) For a base version CTM, check the fused igni-
tion switch output (st-run) fuse (Fuse 11 - 10 ampere)
in the JB. For a high-line/premium version CTM,
check the fused ignition switch output (run-acc) fuse
(Fuse6-25ampere) in the JB. If OK, go to Step 4. If
not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
8E - 4 ELECTRONIC CONTROL MODULESBR/BE
CENTRAL TIMER MODULE (Continued)

(4) Turn the ignition switch to the On position. For
a base version CTM, check for battery voltage at the
fused ignition switch output (st-run) fuse (Fuse 11 -
10 ampere) in the JB. For a high-line/premium ver-
sion CTM, check for battery voltage at the fused igni-
tion switch output (run-acc) fuse (Fuse6-25
ampere) in the JB. If OK, go to Step 5. If not OK,
repair the shorted circuit or component as required
and replace the faulty fuse.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the CTM from its mounting bracket to access
the CTM wire harness connector(s). Disconnect the
instrument panel wire harness connector(s) for the
CTM from the CTM connector receptacle(s). Check
the wire harness connectors and the CTM receptacles
for loose, corroded, or damaged terminals and pins. If
OK, go to Step 6. If not OK, repair as required.
(6) Check for continuity between the ground cir-
cuit cavity of the instrument panel wire harness con-
nector (Connector C1) for the CTM and a good
ground. For the high-line/premium version of the
CTM only, repeat the check between the ground cir-
cuit cavity of the instrument panel wire harness con-
nector (Connector C2) for the CTM and a good
ground. In each case, there should be continuity. If
OK, go to Step 7. If not OK, repair the open ground
circuit(s) to ground as required.
(7) Reconnect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
instrument panel wire harness connector (Connector
C1) for the CTM. If OK, go to Step 8. If not OK,
repair the open fused B(+) circuit between the CTM
and the JB as required.
(8) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (st-run) circuit cavity (base version) or fused
ignition switch output (run-acc) circuit cavity (high-
line/premium version) of the instrument panel wire
harness connector (Connector C1) for the CTM. If OK
with a base version CTM, replace the faulty CTM. If
OK with a high-line/premium version CTM, use a
DRBIIItscan tool and the appropriate diagnostic
information to perform further diagnosis of the CTM.
If not OK, repair the open fused ignition switch out-
put circuit between the CTM and the JB.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: Before replacing a high-line/premium version
Central Timer Module (CTM), use a DRBIIITscan
tool to retrieve the current settings for the CTM pro-
grammable features. Refer to the appropriate diag-
nostic information. These settings should be
duplicated in the replacement high-line/premium
CTM using the DRBIIITscan tool before returning
the vehicle to service.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(3) Remove the two screws that secure the Central
Timer Module (CTM) to the bracket on the inboard
side of the instrument panel steering column opening
(Fig. 3) or (Fig. 4).
(4) Pull the CTM into the instrument panel steer-
ing column opening far enough to access the instru-
ment panel wire harness connector(s).
Fig. 3 Central Timer Module (Base) Remove/Install
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTOR
4 - CENTRAL TIMER MODULE
BR/BEELECTRONIC CONTROL MODULES 8E - 5
CENTRAL TIMER MODULE (Continued)

(5) Disconnect the instrument panel wire harness
connector(s) (one connector for the base version CTM,
two connectors for the high-line/premium version)
from the CTM connector receptacle(s).
(6) Remove the CTM from the instrument panel.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: Before replacing a high-line/premium version
Central Timer Module (CTM), use a DRBIIITscan
tool to retrieve the current settings for the CTM pro-
grammable features. Refer to the appropriate diag-
nostic information. These settings should be
duplicated in the replacement high-line/premiumCTM using the DRBIIITscan tool before returning
the vehicle to service.
(1) Position the CTM to the inboard side of the
instrument panel steering column opening.
(2) Reconnect the instrument panel wire harness
connector(s) for the CTM (one connector for the base
version CTM, two connectors for the high-line/pre-
mium version) to the CTM connector receptacle(s)
(Fig. 3) or (Fig. 4).
(3) Position the CTM to the bracket on the inboard
side of the instrument panel steering column open-
ing.
(4) Install and tighten the two screws that secure
the CTM to the bracket on the inboard side of instru-
ment panel steering column opening. Tighten the
screws to 1.6 N´m (15 in. lbs.).
(5) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(6) Reconnect the battery negative cable.
COMMUNICATION
DESCRIPTION - CCD DATA BUS
The Chrysler Collision Detection (also referred to as
CCD or CD) data bus system is a multiplex system
used for vehicle communications on many
DaimlerChrysler Corporation vehicles. Within the con-
text of the CCD system, the term ªcollisionª refers to
the system's ability to avoid collisions of the electronic
data that enters the data bus from various electronic
control modules at approximately the same time.
Multiplexing is a system that enables the trans-
mission of several messages over a single channel or
circuit. Many DaimlerChrysler vehicles use this prin-
ciple for communication between the various micro-
processor-based electronic control modules.
Many of the electronic control modules in a vehicle
require information from the same sensing device. In
the past, if information from one sensing device was
required by several controllers, a wire from each con-
troller needed to be connected in parallel to that sen-
sor. In addition, each controller utilizing analog
sensors required an Analog/Digital (A/D) converter in
order to ªreadª these sensor inputs. Multiplexing
reduces wire harness complexity, sensor current
loads and controller hardware because each sensing
device is connected to only one controller, which
reads and distributes the sensor information to the
other controllers over the data bus. Also, because
each controller on the data bus can access the con-
troller sensor inputs to every other controller on the
data bus, more function and feature capabilities are
possible.
Fig. 4 Central Timer Module (High-Line/Premium)
Remove/Install
1 - SCREWS
2 - BRACKET
3 - WIRE HARNESS CONNECTORS
4 - CENTRAL TIMER MODULE
8E - 6 ELECTRONIC CONTROL MODULESBR/BE
CENTRAL TIMER MODULE (Continued)

ENGINE CONTROL MODULE
DESCRIPTION - ECM
The ECM is bolted to the left side of the engine
behind the fuel filter (Fig. 14). It is a separate com-
ponent and can be serviced. The FPCM is internal to
the fuel injection pump (Fig. 15) and cannot be ser-
viced.
OPERATION - ECM
The main functions of the Engine Control Module
(ECM) and Fuel Injection Pump Control Module
(FPCM) are to electrically control the fuel system.
The Powertrain Control Module (PCM)does not
controlthe 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
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
²(FPCM) Fuel Injection Pump Control Module
²Engine Coolant Temperature (ECT) sensor
²Ground circuits
²Intake manifold Air Temperature (IAT) sensor
²Manifold Air Pressure Sensor (Boost Pressure
Sensor)
²Oil pressure sensor
²PCM
²Power Take Off (PTO)
²Power ground
²Sensor return
²Signal ground
²Water-In-Fuel (WIF) sensor
Fig. 14 Engine Control Module (ECM) Location
1 - ENGINE CONTROL MODULE (ECM)
2 - HEX HEADED BOLT
3 - 50-WAY CONNECTOR
4 - FUEL TRANSFER PUMP
5 - MOUNTING BOLTS (3)
Fig. 15 Fuel Injection Pump Control Module (FPCM)
Location
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
BR/BEELECTRONIC CONTROL MODULES 8E - 13