Dodge RAM TRUCK 1500 1995 Service Manual page 1699

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E i l S S i O i CONTROL SYSTEMS 25
- 1
" ISSION
CONTROL
SYSTEMS
CONTENTS
page page
AIR INJECTION SYSTEM—HDC-GAS ENGINES . . 15 EMISSION CONTROLS 6
COMPONENT REMOVAL/INSTALLATION . . . . . . 18 GENERAL INFORMATION 1
HENERAL INFORMATION
INDEX
page
DRB Scan Tool 5
On-Board Diagnostics 3
Service Reminder Indicator (SRI) Lamp . . . . . . . . . . 1
Throughout this group, references are made to par­
ticular vehicle models by alphabetical designation or
by the particular vehicle nameplate. A chart showing
a breakdown of alphabetical designations is included
in the Introduction section at the beginning of this
manual.
All vehicles are equipped with either a 3.9L (V-6)
engine, a 5.2L (V-8) engine, two different 5.9L (V-8)
engines, an 8.0L (V-10) engine or a 5.9L (Cummins
in-line 6-cylinder diesel) engine.
The 3.9L (V-6) and 5.2L (V-8) engines will be re­
ferred to in this group as: LDC (Light Duty Cycle)
engines. The 5.9L (V-8) gas powered engine will be
referred to as either: LDC (Light Duty Cycle) or HDC
(Heavy Duty Cycle) engine. The 8.0L (V-10) engine
will be referred to as: HDC (Heavy Duty Cycle) en­
gine.
Either of the HDC gas powered engines can be eas­
ily identified by the use of an engine mounted air in­
jection (AIR) pump. The 3.9L/5.2L/5.9L LDC gas
engines or the diesel engine will not use an AIR
pump.
Maintenance requirements for LDC and HDC emis­
sion systems differ because of different load and op­
erating conditions.
This section will cover emission control systems for
the 3.9L (V-6), 5.2L (V-8), 5.9L LDC (V-8), 5.9L HDC
(V-8), 8.0L (V-10) and 5.9L (in-line six cylinder) diesel
engines.
SERVICE REMINDER INDICATOR (SRI) LAMP
The service reminder indicator (SRI) lamp is used
with 5.9L V-8 HDC and 8.0L V-10 gas powered en-
page
Vacuum Hose Routing Schematics 3
Vehicle Emission Control Information (VECI) Label . 2
gines only. It is not used with diesel engines. The
lamp is displayed on the instrument panel as the
MAINT REQ'D lamp (Fig. 1).
SERVICE REMINDER
INDICATOR LAMP
Fig. 1 SRI Lamp Location
The SRI system is incorporated into the powertrain
control module (PCM). The PCM (Fig. 2) was for­
merly referred to as the engine controller or SBEC.
The PCM records the vehicles mileage and stores it
into memory. At that time, the PCM checks for cer­
tain mileage trip points. When the current mileage
matches one of the trip points, the SRI lamp is acti­
vated.
Certain parts are to be replaced, or certain mainte­
nance must be performed at either an indicated mile­
age or when the SRI lamp remains on when the key
is in the ON position. After performing the part re-