Visual Inspection—3.9/5.2/5.9L Engines - Dodge 2000 DURANGO Service Manual

DN
DESCRIPTION AND OPERATION (Continued)
coolant temperature drops to approximately 98°C
(208°F). Refer to Cooling Systems for additional
information. Equipped With A/C: In addition to
using coolant temperatures to control cooling fan
operation, the cooling fan will also be engaged when
the air conditioning system has been activated. Refer
to Heating and Air Conditioning for additional infor-
mation.
THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold.
Fuel does not enter the intake manifold through the
throttle body. Fuel is sprayed into the manifold by
the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle body linkage arm.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate. Never attempt to adjust the engine idle
speed using this screw. All idle speed functions are
controlled by the PCM.
DIAGNOSIS AND TESTING
VISUAL INSPECTION—3.9/5.2/5.9L ENGINES
A visual inspection for loose, disconnected or incor-
rectly routed wires and hoses should be made. This
should be done before attempting to diagnose or ser-
vice the fuel injection system. A visual check will
help spot these faults and save unnecessary test and
diagnostic time. A thorough visual inspection will
include the following checks:
(1) Verify three 32–way electrical connectors are
fully inserted into connector of powertrain control
module (PCM) (Fig. 3).
(2) Inspect battery cable connections. Be sure they
are clean and tight.
(3) Inspect fuel pump relay and air conditioning
compressor clutch relay (if equipped). Inspect ASD
relay connections. Inspect starter motor relay connec-
tions. Inspect relays for signs of physical damage and
corrosion. The relays are located in Power Distribu-
Fig. 3 Powertrain Control Module (PCM)
1 – RIGHT FRONT FENDER
2 – PCM MOUNTING BOLTS (3)
3 – 32–WAY CONNECTORS (3)
4 – COVER
5 – POWERTRAIN CONTROL MODULE (PCM)
tion Center (PDC) (Fig. 4). Refer to label on PDC
cover for relay location.
Fig. 4 Power Distribution Center (PDC)
1 – POWER DISTRIBUTION CENTER (PDC)
(4) Inspect ignition coil connections. Verify coil sec-
ondary cable is firmly connected to coil (Fig. 5).
(5) Verify distributor cap is correctly attached to
distributor. Be sure spark plug cables are firmly con-
nected to the distributor cap and the spark plugs are
in their correct firing order. Be sure coil cable is
FUEL SYSTEM 14 - 39