1998 DODGE RAM 1500 Data link wiring

The PCI data bus can be monitored using the
DRBIIItscan tool. It is possible, however, for the bus
to pass all DRBIIIttests and still be faulty if the
voltage parameters are all within the specified range
and false messages are being sent.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The Controler Antilock Brake (CAB) is mounted to
the Hydraulic Control Unit (HCU) and operates the
ABS system (Fig. 1).
OPERATION
The CAB voltage source is through the ignition
switch in the RUN position. The CAB contains a self
check program that illuminates the ABS warning
light when a system fault is detected. Faults are
stored in a diagnostic program memory and are
accessible with the DRB III scan tool. ABS faults
remain in memory until cleared, or until after the
vehicle is started approximately 50 times. Stored
faults arenoterased if the battery is disconnected.
NOTE: If the CAB is being replaced with a new CAB
is must be reprogrammed with the use of a DRB III.
REMOVAL
(1) Remove the negative battery cable from the
battery.
(2) Pull up on the CAB harness connector release
and remove connector.
(3) Remove the CAB mounting bolts.
(4) Remove the pump connector from the CAB.
(5) Remove the CAB from the HCU.
INSTALLATION
NOTE: If the CAB is being replaced with a new CAB
is must be reprogrammed with the use of a DRB III.
(1) Install CAB to the HCU.
(2) Install the pump connector to the CAB.
(3) Install mounting bolts. Tighten to 2 N´m (16 in.
lbs.).
(4) Install the wiring harness connector to the
CAB and push down on the release to secure the con-
nector.
(5) Install negative battery cable to the battery.
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR
The Data Link Connector (DLC) is located at the
lower edge of the instrument panel near the steering
column.
OPERATION - DATA LINK CONNECTOR
The 16±way data link connector (diagnostic scan
tool connector) links the Diagnostic Readout Box
(DRB) scan tool or the Mopar Diagnostic System
(MDS) with the Powertrain Control Module (PCM).
ENGINE CONTROL MODULE
DESCRIPTION - ECM
The engine control module (ECM) for the 5.9L Die-
sel engine is bolted to the left side of the engine
below the intake manifold.
OPERATION - ECM
The main function of the Engine Control Module
(ECM) is to electrically control the fuel system. The
Powertrain Control Module (PCM)does notcontrol
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.
Fig. 1 HYDRAULIC CONTROL UNIT
1 - HYDRAULIC CONTROL UNIT
2 - MOUNTING BOLTS
DRELECTRONIC CONTROL MODULES 8E - 3
COMMUNICATION (Continued)

SKIM cannot be repaired and, if faulty or damaged,
the unit must be replaced.
DIAGNOSIS AND TESTING
VEHICLE THEFT SECURITY SYSTEM
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO RESTRAINT SYSTEMS BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
NOTE: The most reliable, efficient, and accurate
means to diagnose the Vehicle Theft Security Sys-
tem (VTSS) and Sentry Key Immobilizer System
(SKIS) involves the use of a DRBlllTscan tool and
the proper Powertrain Diagnostic Procedures man-
ual.
The Vehicle Theft Security System (VTSS), Sentry
Key Immobilizer System (SKIS) and the Programma-
ble Communication Interface (PCI) bus network
should be diagnosed using a DRBIIItscan tool. The
DRBIIItwill allow confirmation that the PCI bus is
functional, that the Sentry Key Immobilizer Module
(SKIM) is placing the proper messages on the PCI
bus, and that the Powertrain Control Module (PCM)
and the Instrument Cluster are receiving the PCI
bus messages. Refer to the proper Powertrain or
Body Diagnostic Procedures manual.
Visually inspect the related wiring harness connec-
tors. Look for broken, bent, pushed out or corroded
terminals. If any of the conditions are present, repair
as necessary. Refer to Wiring Diagrams for complete
circuit descriptions and diagrams. Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/SEN-
TRY KEY IMMOBILIZER MODULE - REMOVAL for
SKIM replacement.
STANDARD PROCEDURE
CONFIGURING A NEW MODULE / SWITCH
OPERATING MODES
To configure a new module or to switch operating
modes, a DRBIIItscan tool must be used.
(1) Hook up the DRBIIItscan tool to the Data
Link Connector (DLC).
(2) With the key in the ignition, turn the key to
the RUN position.(3) After the DRBIIItscan tool initialization, per-
form the following:
(a) Select ªTheft Alarm.º
(b) Select ªVTSS.º
(c) Select ªMiscellaneous.º
(4) Once in the ªMiscellaneousº screen:
(a) If you wish to configure a new module, select
ªConfigure Module.º
(b) If you wish to put the module into customer
usage mode, select ªEnable VTSS.º
(c) If you wish to put the module into dealer lot
mode, select ªDealer Lot.º
SENTRY KEY IMMOBILIZER SYSTEM
INITIALIZATION
The Sentry Key Immobilizer System (SKIS) initial-
ization should be performed following a Sentry Key
Immobilizer Module (SKIM) replacement.
It can be summarized by the following:
(1) Obtain the vehicles unique PIN number
assigned to it's original SKIM from the vehicle
owner, the vehicle's invoice or from Chrysler's Cus-
tomer Center.
(2) With the DRBIIItscan tool, select ªTheft
Alarm,º ªSKIM,º Miscellaneous.º Select ªSKIM Mod-
ule Replacedº function and the DRBIIItwill prompt
you through the following steps.
(3) Enter secured access mode using the unique
four digit PIN number.
(4) Program the vehicle's VIN number into the
SKIM's memory.
(5) Program the country code into the SKIM's
memory (U.S.).
(6) Transfer the vehicle's unique Secret Key data
from the PCM. This process will require the SKIM to
be insecured access mode. The PIN number must
be entered into the DRBIIItbefore the SKIM will
entersecured access mode. Oncesecured access
modeis active, the SKIM will remain in that mode
for 60 seconds.
(7) Program all customer keys into the SKIM's
memory. This required that the SKIM be insecured
access modeThe SKIM will immediately exit
secured access modeafter each key is pro-
grammed.
NOTE: If a PCM is replaced, the unique ªSecret
Keyº data must be transferred from the SKIM to the
PCM. This procedure requires the SKIM to be
placed in SECURED ACCESS MODE using the four
digit PIN code.
DRVEHICLE THEFT SECURITY 8Q - 3
VEHICLE THEFT SECURITY (Continued)

EMISSIONS CONTROL
TABLE OF CONTENTS
page page
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - STATE DISPLAY TEST
MODE...............................1
DESCRIPTION - CIRCUIT ACTUATION TEST
MODE...............................1
DESCRIPTION - DIAGNOSTIC TROUBLE
CODES..............................1
DESCRIPTION - TASK MANAGER..........1DESCRIPTION - MONITORED SYSTEMS....2
DESCRIPTION - TRIP DEFINITION.........4
DESCRIPTION - COMPONENT MONITORS . . 4
OPERATION
OPERATION..........................5
OPERATION - TASK MANAGER...........5
OPERATION - NON-MONITORED CIRCUITS . . 8
EVAPORATIVE EMISSIONS................10
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - STATE DISPLAY TEST MODE
The switch inputs to the Powertrain Control Mod-
ule (PCM) have two recognized states; HIGH and
LOW. For this reason, the PCM cannot recognize the
difference between a selected switch position versus
an open circuit, a short circuit, or a defective switch.
If the State Display screen shows the change from
HIGH to LOW or LOW to HIGH, assume the entire
switch circuit to the PCM functions properly. Connect
the DRB scan tool to the data link connector and
access the state display screen. Then access either
State Display Inputs and Outputs or State Display
Sensors.
DESCRIPTION - CIRCUIT ACTUATION TEST
MODE
The Circuit Actuation Test Mode checks for proper
operation of output circuits or devices the Powertrain
Control Module (PCM) may not internally recognize.
The PCM attempts to activate these outputs and
allow an observer to verify proper operation. Most of
the tests provide an audible or visual indication of
device operation (click of relay contacts, fuel spray,
etc.). Except for intermittent conditions, if a device
functions properly during testing, assume the device,
its associated wiring, and driver circuit work cor-
rectly. Connect the DRB scan tool to the data link
connector and access the Actuators screen.
DESCRIPTION - DIAGNOSTIC TROUBLE CODES
A Diagnostic Trouble Code (DTC) indicates the
PCM has recognized an abnormal condition in the
system.Remember that DTC's are the results of a sys-
tem or circuit failure, but do not directly iden-
tify the failed component or components.
BULB CHECK
Each time the ignition key is turned to the ON
position, the malfunction indicator (check engine)
lamp on the instrument panel should illuminate for
approximately 2 seconds then go out. This is done for
a bulb check.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Obtain the applicable Powertrain Diagnostic
Manual.
(2) Obtain the DRB Scan Tool.
(3) Connect the DRB Scan Tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
(4) Turn the ignition switch on and access the
ªRead Faultº screen.
(5) Record all the DTC's and ªfreeze frameº infor-
mation shown on the DRB scan tool.
(6) To erase DTC's, use the ªErase Trouble Codeº
data screen on the DRB scan tool.Do not erase any
DTC's until problems have been investigated
and repairs have been performed.
DESCRIPTION - TASK MANAGER
The PCM is responsible for efficiently coordinating
the operation of all the emissions-related compo-
nents. The PCM is also responsible for determining if
the diagnostic systems are operating properly. The
software designed to carry out these responsibilities
is call the 'Task Manager'.
DREMISSIONS CONTROL 25 - 1