Dodge Durango (DN). Manual — part 18

firmly connected to distributor cap and coil. Be sure
camshaft position sensor wire connector (at the dis-
tributor) is firmly connected to harness connector.
Inspect spark plug condition. Refer to Group 8D,
Ignition. Connect vehicle to an oscilloscope and
inspect spark events for fouled or damaged spark
plugs or cables.

(6) Verify generator output wire, generator connec-

tor and ground wire are firmly connected to genera-
tor.

(7) Inspect system body grounds for loose or dirty

connections. Refer to Group 8, Wiring for ground
locations.

(8) Verify positive crankcase ventilation (PCV)

valve operation. Refer to Group 25, Emission Control
System for additional information. Verify PCV valve
hose is firmly connected to PCV valve and manifold
(Fig. 6).

(9) Inspect fuel tube quick-connect fitting-to-fuel

rail connections.

(10) Verify hose connections to all ports of vacuum

fittings on intake manifold are tight and not leaking.

(11) Inspect accelerator cable, transmission throt-

tle cable (if equipped) and cruise control cable con-
nections (if equipped). Check their connections to
throttle arm of throttle body for any binding or
restrictions.

(12) If equipped with vacuum brake booster, verify

vacuum booster hose is firmly connected to fitting on
intake manifold. Also check connection to brake vac-
uum booster.

(13) Inspect air cleaner inlet and air cleaner ele-

ment for dirt or restrictions.

(14) Inspect radiator grille area, radiator fins and

air conditioning condenser for restrictions.

(15) Verify intake manifold air temperature sensor

wire connector is firmly connected to harness connec-
tor (Fig. 7).

(16) Verify MAP sensor electrical connector is

firmly connected to MAP sensor (Fig. 8). Also verify
rubber L-shaped fitting from MAP sensor to throttle
body is firmly connected (Fig. 9).

(17) Verify fuel injector wire harness connectors

are firmly connected to injectors in correct order.
Each harness connector is numerically tagged with

Fig. 5 Ignition Coil

1 – ACCESSORY DRIVE BELT TENSIONER
2 – COIL CONNECTOR
3 – IGNITION COIL
4 – COIL MOUNTING BOLTS

Fig. 6 PCV Valve Hose Connections

1 – PCV VALVE
2 – PCV VALVE HOSE CONNECTIONS

Fig. 7 Intake Manifold Air Temperature Sensor—

Typical

1 – INTAKE MANIFOLD AIR TEMPERATURE SENSOR
2 – ELECTRICAL CONNECTOR

14 - 40

FUEL SYSTEM

DN

DIAGNOSIS AND TESTING (Continued)

injector number (INJ 1, INJ 2 etc.) of its correspond-
ing fuel injector and cylinder number.

(18) Verify harness connectors are firmly con-

nected to idle air control (IAC) motor, throttle posi-
tion sensor (TPS) and manifold absolute pressure
(MAP) sensor (Fig. 8).

(19) Verify wire harness connector is firmly con-

nected to engine coolant temperature sensor (Fig.
10).

(20) Raise and support vehicle.
(21) Verify both upstream and downstream oxygen

sensor wire connectors are firmly connected to sen-
sors. Inspect sensors and connectors for damage (Fig.
11) or (Fig. 12).

(22) Inspect for pinched or leaking fuel tubes.

Inspect for pinched, cracked or leaking fuel hoses.

Fig. 8 Sensor and IAC Motor Location—Typical (V-8

Shown)

1 – MAP SENSOR
2 – IDLE AIR CONTROL MOTOR
3 – THROTTLE POSITION SENSOR

Fig. 9 Rubber L-Shaped Fitting—MAP Sensor-to-

Throttle Body

1 – MAP SENSOR
2 – RUBBER FITTING
3 – IDLE AIR PASSAGE

Fig. 10 Engine Coolant Temperature Sensor

1 – GENERATOR
2 – A/C COMPRESSOR
3 – ENGINE COOLANT TEMPERATURE SENSOR
4 – ELEC. CONN.

Fig. 11 Upstream Oxygen Sensor

1 – EXHAUST PIPE
2 – UPSTREAM OXYGEN SENSOR

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FUEL SYSTEM

14 - 41

DIAGNOSIS AND TESTING (Continued)

(23) Inspect for exhaust system restrictions such

as pinched exhaust pipes, collapsed muffler or
plugged catalytic convertor.

(24) If equipped with automatic transmission, ver-

ify electrical harness is firmly connected to park/neu-
tral switch. Refer to Automatic Transmission section
of Group 21.

(25) Verify electrical harness is firmly connected to

rear wheel speed sensor. Verify rear wheel speed sen-
sor is firmly attached to rear axle with proper air
gap. Refer to Group 5, Brakes for information.

(26) If equipped with 4–wheel antilock brake sys-

tem, verify electrical harness is firmly connected to
each front wheel speed sensor. Verify both front
wheel speed sensors are firmly attached. Refer to
Group 5, Brakes for information.

(27) Verify fuel pump/gauge sender unit wire con-

nector is firmly connected to harness connector.

(28) Inspect fuel hoses at fuel pump/gauge sender

unit for cracks or leaks.

(29) Inspect transmission torque convertor housing

(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.

(30) Verify battery cable and solenoid feed wire

connections to starter solenoid are tight and clean.
Inspect for chaffed wires or wires rubbing against
other components.

ASD AND FUEL PUMP RELAYS

The following description of operation and

tests apply only to the Automatic Shutdown
(ASD) and fuel pump relays. The terminals on the
bottom of each relay are numbered (Fig. 13).

OPERATION

• Terminal number 30 is connected to battery volt-

age. For both the ASD and fuel pump relays, termi-
nal 30 is connected to battery voltage at all times.

• The PCM grounds the coil side of the relay

through terminal number 85.

• Terminal number 86 supplies voltage to the coil

side of the relay.

• When the PCM de-energizes the ASD and fuel

pump relays, terminal number 87A connects to termi-
nal 30. This is the Off position. In the off position,
voltage is not supplied to the rest of the circuit. Ter-
minal 87A is the center terminal on the relay.

• When the PCM energizes the ASD and fuel

pump relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.

TESTING

The following procedure applies to the ASD and

fuel pump relays.

(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use

an ohmmeter to check the resistance between termi-
nals 85 and 86. The resistance should be 75

65

ohms.

(3) Connect the ohmmeter between terminals 30

and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.

(4) Connect the ohmmeter between terminals 87

and 30. The ohmmeter should not show continuity at
this time.

Fig. 12 Downstream Oxygen Sensor

1 – DOWNSTREAM OXYGEN SENSOR
2 – FRAME RAIL
3 – CATALYTIC CONVERTER

TERMINAL LEGEND

NUMBER

IDENTIFICATION

30

COMMON FEED

85

COIL GROUND

86

COIL BATTERY

87

NORMALLY OPEN

87A

NORMALLY CLOSED

Fig. 13 ASD and Fuel Pump Relay Terminals

14 - 42

FUEL SYSTEM

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DIAGNOSIS AND TESTING (Continued)

(5) Connect one end of a jumper wire (16 gauge or

smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.

(6) Connect one end of another jumper wire (16

gauge or smaller) to the power side of the 12 volt
power source. Do not attach the other end of the
jumper wire to the relay at this time.

WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.

(7) Attach the other end of the jumper wire to

relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.

(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-

ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to group 8W, Wir-
ing Diagrams.

THROTTLE BODY MINIMUM AIR FLOW CHECK
PROCEDURE

3.9/5.2/5.9L ENGINES

The following test procedure has been developed to

check throttle body calibrations for correct idle condi-
tions. The procedure should be used to diagnose the
throttle body for conditions that may cause idle prob-
lems. This procedure should be used only after
normal diagnostic procedures have failed to
produce results that indicate a throttle body
related problem. Be sure to check for proper
operation of the idle air control motor before
performing this test.

A special fixed orifice tool (number 6714) (Fig. 14)

must be used for the following test.

(1) Start the engine and bring to operating tem-

perature. Be sure all accessories are off before per-
forming this test.

(2) Shut off the engine and remove the air duct at

throttle body.

(3) Disconnect the vacuum line at the PCV valve

(Fig. 15).

(4) Install the 0.185 inch orifice tool (number 6714)

into the disconnected vacuum line in place of the
PCV valve (Fig. 15).

Fig. 14 Fixed Orifice Tool

Fig. 15 Install Orifice Tool

1 – PCV VALVE
2 – VACUUM LINE
3 – ORIFICE TOOL

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FUEL SYSTEM

14 - 43

DIAGNOSIS AND TESTING (Continued)