Dodge RAM 1500 1998 Owner's Manual page 2562

DR
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - STATE DISPLAY TEST
MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION - CIRCUIT ACTUATION TEST
MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION - DIAGNOSTIC TROUBLE
CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION - TASK MANAGER . . . . . . . . . . 1
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.
EMISSIONS CONTROL
TABLE OF CONTENTS
page
OPERATION
EVAPORATIVE EMISSIONS
tem or circuit failure, but do not directly iden-
tify the failed component or components.
BULB CHECK
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
Manual.
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
"Read Fault" screen.
mation shown on the DRB scan tool.
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 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'.
EMISSIONS CONTROL
DESCRIPTION - MONITORED SYSTEMS
DESCRIPTION - TRIP DEFINITION
DESCRIPTION - COMPONENT MONITORS
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 5
OPERATION - TASK MANAGER
OPERATION - NON-MONITORED CIRCUITS
Remember that DTC's are the results of a sys-
Each time the ignition key is turned to the ON
(1) Obtain the applicable Powertrain Diagnostic
(2) Obtain the DRB Scan Tool.
(3) Connect the DRB Scan Tool to the data link
(4) Turn the ignition switch on and access the
(5) Record all the DTC's and "freeze frame" infor-
(6) To erase DTC's, use the "Erase Trouble Code"
The PCM is responsible for efficiently coordinating
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