Power control DODGE RAM 1500 1998 2.G User Guide

LEAKS
Viscous fan drive operation is not affected by small
oil stains near the drive bearing. If leakage appears
excessive, replace the fan drive unit.
ELECTRONICALLY CONTROLLED VISCOUS DRIVE
If the fan assembly free-wheels without drag (the
fan blades will revolve more than five turns when
spun by hand), do not replace the fan drive. This
spin test must be performed when the engine is cool.
If the fan assembly does not free-wheel and a
metallic grinding sound exists, replace the electroni-
cally controlled fan drive (Refer to 7 - COOLING/EN-
GINE/RADIATOR FAN - REMOVAL).
NOTE: The following test may take up to 15 minutes
to perform.
The engine should be at normal operating temper-
ature.
(1) Set the parking brake and verify the transmis-
sion is in park or neutral.
(2) Set air conditioner (if equipped) and blower fan
to OFF.
(3) Start and allow engine to reach normal operat-
ing temperatures.
(4) Stop engine, connect the DRB III and select
appropriate model year and engine option.
(5) Check for and correct existing DTC's
(6) Using Tool 6801, connect pin 1 of the electron-
ically controlled viscous fan drive connector, located
at the lower fan shroud to battery ground (Fig. 35).
(7) Using the DRB III, verify that DTC 0480 set.
(8) Start the engine.
(9) Go to the SENSOR screen and observe the fan
speed.
(10) Run the engine at 2500 rpm.
NOTE: It maybe take 15 minutes before fan speed
increases.
(11) The fan speed should increase according to
the table below.
(12) If fan speed does not increase, replace the
electronically control viscous fan drive.
ELECTRONICALLY CONTROLLED VISCOUS FAN
DRIVE SPEEDS
ENGINE RPM FAN RPM(Min)
500 490
1000 950
1500 1420
2000 1850
2500 2230
3000 2440
(13) If the fan speed does increase and there is
still a concern, refer to the appropriate Powertrain
Diagnosis Manual to diagnosis the electronically con-
trolled viscous fan drive control circuit.
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks or chips that could result in excessive vibra-
tion. Replace fan blade assembly if any of these
conditions are found.
Fig. 35 Electronically Controlled Viscous Fan Drive
Connector
1 - ELECTRONICALLY CONTROLLED VISCOUS FAN DRIVE
CONNECTOR
2 - TOOL 6801
3 - PIN 1
DRENGINE 7 - 53
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL (Continued)

INSTALLATION
(1) Install rubber insulators to alignment dowels
at lower part of radiator.
(2) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(3) Install two upper radiator mounting bolts.
Tighten bolts to 11.8 N´m (105 in. lbs.) torque.
(4) Connect both radiator hoses and install hose
clamps.
(5) Connect transmission cooler lines to transmis-
sion cooler. Inspect quick connect fittings for debris
and install until an audible ªclickº is heard. Pull
apart to verify connection.
(6) Position power steering cooler on the radiator
and tighten nuts to 10 N´m (90 in. lbs.)
(7) Position the electronic viscous fan wiring in the
channel in the upper shroud (Fig. 39). Make sure
that the grommet seats into the channel.
(8) Install lower radiator shroud using two push
pins. Make sure the wiring viscous fan drive wiring
is not pinched.
(9) Install the wiring harness bracket to the upper
shroud.
(10) Connect the viscous fan drive wiring to the
wiring harness.(11) Install the coolant recovery container (Refer to
7 - COOLING/ENGINE/COOLANT RECOVERY
CONTAINER - INSTALLATION).
(12) Position coolant recovery tank hose, washer
bottle hose and the positive battery cable into the
clips located on the top of the radiator.
(13) Install air box and turbocharger inlet hose.
Tighten clamps to 4 N´m (35 in. lbs.).
(14) Position heater controls tofull heatposition.
(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate engine until it reaches normal tem-
perature. Check cooling system and automatic trans-
mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP
DESCRIPTION
All cooling systems are equipped with a pressure
cap (Fig. 40). For 5.9L engines, the pressure cap is
located on top of the radiator outlet tank. For all
engines, the pressure cap is located on top of the
coolant degas container. The cap releases pressure at
some point within a range of 97-to-124 kPa (14-to-18
psi). The pressure relief point (in pounds) is engraved
on top of the cap
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap contains a spring-
Fig. 38 Fan Shroud Mounting - 5.9L Diesel Engine
1 - RADIATOR SUPPORT
2 - UPPER FAN SHROUD
3 - BOLTS (2)
4 - LOWER FAN SHROUD
5 - RADIATOR
Fig. 39 Electronically Controlled Viscous Fan Drive
Wiring
1 - UPPER SHROUD
2 - WIRING
DRENGINE 7 - 57
RADIATOR - 5.9L DIESEL (Continued)

REMOVAL
NOTE:
The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
The water pump on all gas powered engines is
bolted directly to the engine timing chain case/
cover.
On the 8.0L V-10 engine, a rubber o-ring (instead of
a gasket) is used as a seal between the water pump
and timing chain case/cover.
If water pump is replaced because of bearing/shaft
damage or leaking shaft seal, the mechanical cooling
fan assembly should also be inspected. Inspect for
fatigue cracks, loose blades or loose rivets that could
have resulted from excessive vibration. Replace fan if
any of these conditions are found. Also check condi-
tion of the thermal viscous fan drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - DIAGNOSIS AND TESTING).
(1) Disconnect negative battery cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
(3) Remove windshield washer reservoir tank from
radiator fan shroud.
(4) Remove the four fan shroud mounting bolts at
the radiator (Fig. 51). Do not attempt to remove
shroud from vehicle at this time.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL NUMBER
6094. ALWAYS WEAR SAFETY GLASSES WHEN
SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(5) Remove radiator upper hose at radiator.
(6) The thermal viscous fan drive is threaded on to
the water pump hub shaft (Fig. 53). Remove the fan/
fan drive assembly from water pump by turning the
mounting nut counterclockwise (as viewed from
front). Threads on the fan drive areRIGHT-HAND.
A 36 MM fan wrench can be used with Tool 6958
Spanner Wrench and Adapter Pins 8346 (Fig. 52) to
prevent the pulley from rotating.
(7) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 53) from the thermal control
fan drive.
(8) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
After removing fan blade/fan drive assembly,do
notplace the thermal viscous fan drive in the hori-
zontal position. If stored horizontally, the silicone
Fig. 51 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
Fig. 52 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 64 ENGINEDR
WATER PUMP - 8.0L (Continued)

The optional navigation radio system receives GPS
signals from up to eight satellites to display the posi-
tion and direction of the vehicle. Map information is
supplied through a DVD-ROM. An electronic gyro-
sensor and the vehicle's speed sensor enable the sys-
tem to display the present vehicle position even in
locations where GPS signals may be blocked.
When a destination is selected, the navigation sys-
tem uses information from the map to quickly calcu-
late a route. As the vehicle is driven along the chosen
route, the operator is guided with pictorial displays
and voice prompts. For complete operating instruc-
tions, refer to the manual included with the vehicle.
On vehicles that are equipped with the optional
remote radio switches, the Instrument Cluster
receives hard wired resistor multiplexed inputs from
the remote radio switches. The programming in the
Instrument Cluster allows it to process those inputs
and send the proper messages to the radio receiver
over the Programmable Communication Interface
(PCI) bus network to control the radio volume up or
down, station seek up or down, preset station
advance, and mode advance functions.DIAGNOSIS AND TESTING - AUDIO
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the
DRB IIIt, refer to the appropriate Diagnostic
Service Manual.
Refer to the appropriate wiring information.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
AUDIO SYSTEM DIAGNOSIS TABLE
CONDITION POSSIBLE CAUSES CORRECTION
NO AUDIO 1. Fuse faulty. 1. Check radio fuse and Ignition-Off Draw (IOD)
fuse in the Integrated Power Module (IPM).
Replace fuses, if required.
2. Radio/amplifier (if
equipped) connector faulty.2. Check for loose or corroded radio/amplifier
connector. Repair, if required.
3. Wiring faulty. 3. Check for shorted or open wires. Repair wiring,
if required.
4. Radio/amplifier (if
equipped) ground faulty.4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Radio/amplifier (if
equipped) faulty.5. Refer to appropriate Diagnostic Service
Manual.
6. Speakers faulty. 6. Replace speaker as necessary.
NO RADIO DISPLAY 1. Fuse faulty. 1. Check radio fuse and Ignition-Off Draw (IOD)
fuse in Integrated Power Module (IPM). Replace
fuses, if required.
2. Radio connector faulty. 2. Check for loose or corroded radio connector.
Repair, if required.
3. Wiring faulty. 3. Check for battery voltage at radio connector.
Repair wiring, if required.
4. Radio ground faulty. 4. Check for continuity between radio chassis and
a known good ground. There should be
continuity. Repair ground, if required.
5. Radio faulty. 5. Refer to appropriate Diagnostic Service
Manual.
8A - 2 AUDIO/VIDEODR
AUDIO (Continued)

RADIO NOISE SUPPRESSION
GROUND STRAP
DESCRIPTION
Radio noise suppression devices are factory-in-
stalled standard equipment on this vehicle. Radio
Frequency Interference (RFI) and ElectroMagnetic
Interference (EMI) can be produced by any on-board
or external source of electromagnetic energy. These
electromagnetic energy sources can radiate electro-
magnetic signals through the air, or conduct them
through the vehicle electrical system.
When the audio system converts RFI or EMI to an
audible acoustic wave form, it is referred to as radio
noise. This undesirable radio noise is generally man-
ifested in the form of ªbuzzing,º ªhissing,º ªpopping,º
ªclicking,º ªcrackling,º and/or ªwhirringº sounds. In
most cases, RFI and EMI radio noise can be sup-
pressed using a combination of vehicle and compo-
nent grounding, filtering and shielding techniques.
This vehicle is equipped with factory-installed radio
noise suppression devices that were designed to min-
imize exposure to typical sources of RFI and EMI;
thereby, minimizing radio noise complaints.
Factory-installed radio noise suppression is accom-
plished primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical com-
ponents such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
²Engine-to-body ground strap- This length of
braided ground strap has an eyelet terminal connec-
tor crimped to each end. One end is secured to the
engine cylinder head(s). The other is secured to the
plenum at the exhaust heat shield forward/outer
attaching stud.
²Resistor-type spark plugs- This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center elec-
trode to help reduce the production of electromag-
netic radiation that can result in radio noise.
OPERATION
There are two common strategies that can be used
to suppress Radio Frequency Interference (RFI) and
ElectroMagnetic Interference (EMI) radio noise. The
first suppression strategy involves preventing the
production of RFI and EMI electromagnetic signals
at their sources. The second suppression strategy
involves preventing the reception of RFI and EMIelectromagnetic signals by the audio system compo-
nents.
The use of braided ground straps in key locations
is part of the RFI and EMI prevention strategy.
These ground straps ensure adequate ground paths,
particularly for high current components such as
many of those found in the starting, charging, igni-
tion, engine control and transmission control sys-
tems. An insufficient ground path for any of these
high current components may result in radio noise
caused by induced voltages created as the high cur-
rent seeks alternative ground paths through compo-
nents or circuits intended for use by, or in close
proximity to the audio system components or circuits.
Preventing the reception of RFI and EMI is accom-
plished by ensuring that the audio system compo-
nents are correctly installed in the vehicle. Loose,
corroded or improperly soldered wire harness connec-
tions, improperly routed wiring and inadequate audio
system component grounding can all contribute to
the reception of RFI and EMI. A properly grounded
antenna body and radio chassis, as well as a shielded
antenna coaxial cable with clean and tight connec-
tions will each help reduce the potential for reception
of RFI and EMI.
REMOVAL
BED TO CAB
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the attaching bolts and strap (Fig. 10).
Fig. 10 BED TO CAB GROUND STRAP
1 - BED
2 - CAB
3 - GROUND STRAP
4 - MOUNTING BOLTS
DRAUDIO/VIDEO 8A - 9

REMOTE RADIO SWITCH TEST TABLE
Switch Switch Position Resistance
Right
(White)Volume Up1.210 Kilohms
 1%
Right
(White)Volume Down3.010 Kilohms
 1%
Right
(White)Mode Advance0.0511 Kilohms
 1%
Left
(Black)Seek Up0.261 Kilohms
 1%
Left
(Black)Seek Down0.681 Kilohms
 1%
Left
(Black)Pre-Set Station
Advance0.162 Kilohms
 1%
(3) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for 5 volts
at the radio control mux circuit cavities of the steer-
ing wheel wire harness connectors for both remote
radio switches. If OK, go to Step 4. If not OK, repair
the open or shorted radio control mux circuit to the
Integrated Power Module (IPM) as required.
(4) Disconnect and isolate the battery negative
cable. Disconnect the 22-way instrument panel wire
harness connector from the IPM. Check for continu-
ity between the remote radio switch ground circuit
cavities of the steering wheel wire harness connec-
tors for both remote radio switches and a good
ground. There should be no continuity. If OK, go to
Step 5. If not OK, repair the shorted remote radio
switch ground circuit to the IPM as required.
(5) Check for continuity between the remote radio
switch ground circuit cavities of the steering wheel
wire harness connectors for both remote radio
switches and the 22-way instrument panel wire har-
ness connector for the IPM. There should be continu-
ity. If OK, refer to the proper Diagnostic Procedures
manual to test the IPM and the PCI data bus. If not
OK, repair the open remote radio switch ground cir-
cuit as required.
REMOVAL
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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 AIRBAGSYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver airbag from the vehicle
(Refer to 8 - ELECTRICAL/RESTRAINTS/DRIVER
AIRBAG - REMOVAL).
(3) Remove the speed control switches (Refer to 8 -
ELECTRICAL/SPEED CONTROL/SWITCH -
REMOVAL).
(4) Unplug the wire harness connector from the
remote radio switch(es).
(5) Depress the tabs on each side of each switch
and push the switch through the rear steering wheel
cover (Fig. 16).
INSTALLATION
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
Fig. 16 REMOTE SWITCHES
1 - REMOTE SWITCH
2 - SPEED CONTROL SWITCH
3 - BOLT
8A - 12 AUDIO/VIDEODR
REMOTE SWITCHES (Continued)

(1) Install remote radio switch to the steering
wheel.
(2) Connect the wire harness to the remote radio
switch.
(3) Install the speed control switches (Refer to 8 -
ELECTRICAL/SPEED CONTROL/SWITCH -
INSTALLATION).
(4) Install the driver airbag
(5) Connect the battery negative cable.
SPEAKER
DESCRIPTION
STANDARD
The standard equipment speaker system includes
speakers in four locations. One 15.2 X 22.8 centime-
ter (6 X 9 inch) full-range speaker is located in each
front door. There is also one full-range 13.3 centime-
ter (5.25 inch) diameter full-range speaker located in
each rear door.
PREMIUM
The optional premium speaker system features
eleven Premium model speakers in seven locations.
Each of the standard speakers is replaced with Pre-
mium model speakers. One 8.8 centimeter (3.50 inch)
diameter speaker is located on each end of the
instrument panel top pad. One 6.3 centimeter (2.50
inch) diameter speaker is located in the center of the
instrument panel top pad. One 15.2 X 22.8 centime-
ter (6 X 9 inch) Premium speaker is located in each
front door. There is also one coaxial 13.3 centimeter
(5.25 inch) diameter Premium full-range speaker
located in each rear door. The premium speaker sys-
tem also includes a power amplifier mounted behind
the glove box. The total available power of the pre-
mium speaker system is 240 watts.
OPERATION
Two wires connected to each speaker, one feed cir-
cuit (+) and one return circuit (±), allow the audio
output signal electrical current to flow through the
voice coil. For complete circuit diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
DIAGNOSIS AND TESTING - SPEAKER
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the
DRB IIIt, refer to the appropriate Diagnostic
Service Manual.
Refer to the appropriate wiring information.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
CAUTION: The speaker output of the radio is a
ªfloating groundº system. Do not allow any speaker
lead to short to ground, as damage to the radio
and/or amplifier may result.
(1) If all speakers are inoperative, check the fuses
in the Integrated Power Module (IPM). If OK, go to
Step 2. If not OK, repair the shorted circuit or com-
ponent as required and replace the faulty fuse.
(2) Check the amplifier fuse (if equipped) in the
IPM. If OK, go to Step 3. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(3) Turn the ignition switch to the ON position.
Turn the radio receiver ON. Adjust the balance and
fader control controls to check the performance of
each individual speaker. Note the speaker locations
that are not performing correctly. Go to Step 4.
(4) Turn the radio receiver OFF. Turn the ignition
OFF. Disconnect and isolate the battery negative
cable. If vehicle isnotequipped with a amplifier,
remove the radio receiver. If vehicle is equipped with
an amplifier. disconnect wire harness connector at
output side of amplifier. Go to Step 5.
(5) Check both the speaker feed (+) circuit and
return (-) circuit cavities for the inoperative speaker
at the radio receiver wire harness connector for con-
tinuity to ground. There should be no continuity. If
OK, go to Step 6. If not OK, repair the shorted
speaker feed (+) and/or return (-) circuits(s) to the
speaker as required.
DRAUDIO/VIDEO 8A - 13
REMOTE SWITCHES (Continued)

CHIME/BUZZER
TABLE OF CONTENTS
page page
CHIME WARNING SYSTEM
DESCRIPTION..........................1
OPERATION............................1DIAGNOSIS AND TESTING - CHIME
WARNING SYSTEM.....................3
CHIME WARNING SYSTEM
DESCRIPTION
A chime warning system is standard factory-in-
stalled equipment on this model. The chime warning
system uses a single chime tone generator that is
integral to the instrument cluster to provide an audi-
ble indication of various vehicle conditions that may
require the attention of the vehicle operator. The
chime warning system includes the following major
components, which are described in further detail
elsewhere in this service information:
²Door Ajar Switch- A door ajar switch is inte-
gral to each door latch. This switch provides an input
to the chime warning system indicating whether the
front doors are open or closed.
²Ignition Switch- A key-in ignition switch is
integral to the ignition switch. The key-in ignition
switch provides an input to the chime warning sys-
tem indicating whether a key is present in the igni-
tion lock cylinder.
²Instrument Cluster- The instrument cluster
contains an integral chime tone generator, integrated
circuitry, a central processing unit and the program-
ming to provide all of the proper chime warning sys-
tem features based upon the monitored inputs. The
instrument cluster circuitry monitors hard-wired
switch inputs, as well as message inputs received
from other vehicle electronic modules on the Pro-
grammable Communications Interface (PCI) data bus
network.
²Headlamp Switch- The headlamp switch pro-
vides an input to the chime warning system indicat-
ing when the exterior lamps are turned On or Off.
²Seat Belt Switch- A seat belt switch is inte-
gral to the driver seat belt buckle-half unit. The seat
belt switch provides an input to the chime warning
system indicating whether the driver seat belt is fas-
tened.
Hard wired circuitry connects many of the chime
warning system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained bymany different methods. Refer to the appropriate
wiring information.
The instrument cluster chime warning system cir-
cuitry and the integral chime tone generator cannot
be adjusted or repaired. If the instrument cluster or
the chime tone generator are damaged or faulty, the
instrument cluster must be replaced.
OPERATION
The chime warning system is designed to provide
an audible output as an indication of various condi-
tions that may require the attention or awareness of
the vehicle operator. The chime warning system com-
ponents operate on battery voltage received through
the Ignition-Off Draw (IOD) fuse in the Power Distri-
bution Center (PDC) so that the system may operate
regardless of the ignition switch position.
The chime warning system provides an audible
warning to the vehicle operator under the following
conditions:
²Air Bag Warning- The instrument cluster
chime tone generator will generate a single chime
tone when the airbag indicator is illuminated for an
airbag system fault condition. The instrument cluster
uses airbag indicator lamp-on and lamp-off message
inputs received from the Airbag Control Module
(ACM) over the Programmable Communications
Interface (PCI) data bus indicating that the airbag
indicator should be illuminated for an airbag system
fault condition.
²Door Ajar Warning- The instrument cluster
chime tone generator will generate a single chimes to
announce that the hard wired inputs from the door
ajar switches and the ignition switch as well as an
engine speed message input received from the PCM
over the PCI data bus indicate that a driver or pas-
senger door is opened with the ignition switch in the
On position and vehicle speed present.
²Engine Coolant Temperature High Warning
(Diesel Engine Only)- The instrument cluster
chime tone generator will generate a single chime
tone when the check gauges indicator is illuminated
for a high or critical engine coolant temperature con-
dition. The instrument cluster uses engine coolant
temperature message inputs received from the diesel
DRCHIME/BUZZER 8B - 1

ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
COMMUNICATION
DESCRIPTION..........................1
OPERATION............................2
CONTROLLER ANTILOCK BRAKE
DESCRIPTION..........................3
OPERATION............................3
REMOVAL.............................3
INSTALLATION..........................3
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR.....3
OPERATION - DATA LINK CONNECTOR......3
ENGINE CONTROL MODULE
DESCRIPTION - ECM.....................3
OPERATION - ECM......................3
REMOVAL.............................4
INSTALLATION..........................4
FRONT CONTROL MODULE
DESCRIPTION..........................5
OPERATION............................5
DIAGNOSIS AND TESTING - FRONT
CONTROL MODULE....................5
REMOVAL.............................5
INSTALLATION..........................5
HEATED SEAT MODULE
DESCRIPTION..........................6
OPERATION............................6
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE.............................6
REMOVAL.............................7
INSTALLATION..........................7
POWERTRAIN CONTROL MODULE
DESCRIPTION
DESCRIPTION - PCM...................7DESCRIPTION - MODES OF OPERATION....7
DESCRIPTION - 5 VOLT SUPPLIES.......10
DESCRIPTION - IGNITION CIRCUIT SENSE . 10
DESCRIPTION - POWER GROUNDS......10
DESCRIPTION - SENSOR RETURN.......10
OPERATION
OPERATION - PCM....................10
OPERATION - 5 VOLT SUPPLIES.........11
OPERATION - IGNITION CIRCUIT SENSE . . . 11
REMOVAL.............................12
INSTALLATION.........................12
SENTRY KEY IMMOBILIZER MODULE
DESCRIPTION.........................13
OPERATION...........................13
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING......................14
REMOVAL.............................15
INSTALLATION.........................15
TRANSFER CASE CONTROL MODULE
DESCRIPTION.........................16
OPERATION...........................16
TRANSMISSION CONTROL MODULE
DESCRIPTION.........................20
OPERATION...........................20
STANDARD PROCEDURE
STANDARD PROCEDURE - TCM QUICK
LEARN..............................23
STANDARD PROCEDURE - DRIVE LEARN . . 23
COMMUNICATION
DESCRIPTION
The DaimlerChrysler Programmable Communica-
tion Interface (PCI) data bus system is a single wire
multiplex system used for vehicle communications on
many DaimlerChrysler Corporation vehicles. Multi-
plexing is a system that enables the transmission of
several messages over a single channel or circuit. All
DaimlerChrysler vehicles use this principle for com-
munication between various microprocessor-based
electronic control modules. The PCI data bus exceeds
the Society of Automotive Engineers (SAE) J1850
Standard for Class B Multiplexing.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 to9read9these 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
DRELECTRONIC CONTROL MODULES 8E - 1

data bus, more function and feature capabilities are
possible.
In addition to reducing wire harness complexity,
component sensor current loads and controller hard-
ware, multiplexing offers a diagnostic advantage. A
multiplex system allows the information flowing
between controllers to be monitored using a diagnos-
tic scan tool. The DaimlerChrysler system allows an
electronic control module to broadcast message data
out onto the bus where all other electronic control
modules can9hear9the messages that are being sent.
When a module hears a message on the data bus
that it requires, it relays that message to its micro-
processor. Each module ignores the messages on the
data bus that are being sent to other electronic con-
trol modules.
OPERATION
Data exchange between modules is achieved by serial
transmission of encoded data over a single wire broad-
cast network. The wire colors used for the PCI data bus
circuits are yellow with a violet tracer, or violet with a
yellow tracer, depending upon the application. The PCI
data bus messages are carried over the bus in the form
of Variable Pulse Width Modulated (VPWM) signals.
The PCI data bus speed is an average 10.4 Kilo-bits per
second (Kbps). By comparison, the prior two-wire
Chrysler Collision Detection (CCD) data bus system is
designed to run at 7.8125 Kbps.
The voltage network used to transmit messages
requires biasing and termination. Each module on
the PCI data bus system provides its own biasing
and termination. Each module (also referred to as a
node) terminates the bus through a terminating
resistor and a terminating capacitor. There are two
types of nodes on the bus. The dominant node termi-
nates the bus througha1KWresistor and a 3300 pF
capacitor. The Powertrain Control Module (PCM) is
the only dominant node for the PCI data bus system.
A standard node terminates the bus through an 11
KW resistor and a 330 pF capacitor.
The modules bias the bus when transmitting a
message. The PCI bus uses low and high voltage lev-
els to generate signals. Low voltage is around zero
volts and the high voltage is about seven and one-
half volts. The low and high voltage levels are gener-
ated by means of variable-pulse width modulation to
form signals of varying length. The Variable Pulse
Width Modulation (VPWM) used in PCI bus messag-
ing is a method in which both the state of the bus
and the width of the pulse are used to encode bit
information. A9zero9bit is defined as a short low
pulse or a long high pulse. A9one9bit is defined as a
long low pulse or a short high pulse. A low (passive)
state on the bus does not necessarily mean a zero bit.
It also depends upon pulse width. If the width isshort, it stands for a zero bit. If the width is long, it
stands for a one bit. Similarly, a high (active) state
does not necessarily mean a one bit. This too depends
upon pulse width. If the width is short, it stands for
a one bit. If the width is long, it stands for a zero bit.
In the case where there are successive zero or one
data bits, both the state of the bus and the width of
the pulse are changed alternately. This encoding
scheme is used for two reasons. First, this ensures
that only one symbol per transition and one transi-
tion per symbol exists. On each transition, every
transmitting module must decode the symbol on the
bus and begin timing of the next symbol. Since tim-
ing of the next symbol begins with the last transition
detected on the bus, all of the modules are re-syn-
chronized with each symbol. This ensures that there
are no accumulated timing errors during PCI data
bus communication.
The second reason for this encoding scheme is to
guarantee that the zero bit is the dominant bit on
the bus. When two modules are transmitting simul-
taneously on the bus, there must be some form of
arbitration to determine which module will gain con-
trol. A data collision occurs when two modules are
transmitting different messages at the same time.
When a module is transmitting on the bus, it is read-
ing the bus at the same time to ensure message
integrity. When a collision is detected, the module
that transmitted the one bit stops sending messages
over the bus until the bus becomes idle.
Each module is capable of transmitting and receiv-
ing data simultaneously. The typical PCI bus mes-
sage has the following four components:
²Message Header- One to three bytes in length.
The header contains information identifying the mes-
sage type and length, message priority, target mod-
ule(s) and sending module.
²Data Byte(s)- This is the actual message that
is being sent.
²Cyclic Redundancy Check (CRC) Byte- This
byte is used to detect errors during a message trans-
mission.
²In-Frame Response (IFR) byte(s)-Ifa
response is required from the target module(s), it can
be sent during this frame. This function is described
in greater detail in the following paragraph.
The IFR consists of one or more bytes, which are
transmitted during a message. If the sending module
requires information to be received immediately, the
target module(s) can send data over the bus during
the original message. This allows the sending module
to receive time-critical information without having to
wait for the target module to access the bus. After
the IFR is received, the sending module broadcasts
an End of Frame (EOF) message and releases control
of the bus.
8E - 2 ELECTRONIC CONTROL MODULESDR
COMMUNICATION (Continued)