1999 DODGE RAM Service Repair Manual

Fig. 4: Locating Intake Manifold Air Heater Relays
Courtesy of Chrysler Corp.
Transmission Relay (A/T Models)
Transmission relay may be referred to as transmission control
relay or transmission 12-volt supply relay. Transmission relay is
located in power distribution center at driver's side front corner of
engine compartment, near battery. If problem exists in transmission
relay or wiring circuit, a Diagnostic Trouble Code (DTC) will be
stored in Powertrain Control Module (PCM). See DTC P1765: TRANSMISSION\
12-VOLT SUPPLY RELAY CONTROL CIRCUIT test in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
SOLENOIDS
Transmission Overdrive Solenoid (A/T Models)
See TRANSMISSION under MISCELLANEOUS CONTROLS.

Transmission Torque Converter Clutch Solenoid (A/T Models)
See TRANSMISSION under MISCELLANEOUS CONTROLS.
Fig. 5: Locating Fuel System Components
Courtesy of Chrysler Corp.
FUEL SYSTEM

FUEL DELIVERY
Fuel Filter/Water Separator
1) A restricted fuel filter/water separator may cause engine
starting problems, prevent engine from accelerating, low power or
White exhaust smoke.
2) When ignition is first turned on, WATER-IN-FUEL (WIF)
warning light should come on for 2 seconds to perform bulb and wiring
circuit test and then go off. WATER-IN-FUEL (WIF) warning light is
located on instrument panel, just below tachometer.
3) If WATER-IN-FUEL (WIF) warning light stays on, water
should be drained from fuel filter/water separator. To drain water
from fuel filter/water separator, ensure engine is not running. Place
drain pan below drain tube at fuel filter/water separator.
4) Rotate handle on drain valve forward, toward front of
vehicle to DRAIN position. Drain valve is located near top of fuel
filter/water separator.
5) If no water exists and a clean flow of diesel fuel exists,
rotate handle on drain valve back to CLOSE position. Go to next step.
If water exists, allow water to drain until clean flow of diesel fuel
exists. Rotate handle on drain valve back to CLOSE position. Go to
next step.
6) Verify fuel filter/water separator has been serviced
according to proper service schedule. See SERVICE & ADJUSTMENT
SPECIFICATIONS - TRUCKS article. Ensure pre-filter was cleaned when
fuel filter/water separator was serviced. Pre-filter is located at
bottom of fuel heater on driver's side of engine. No other testing
information is available from manufacturer.
Fuel Heater
1) Malfunctioning fuel heater may cause excessive wax build-
up in fuel filter/water separator during cold ambient temperatures.
Wax build-up may cause hard starting, prevent engine from
accelerating, low power, or Blue or White smoke.
2) Disconnect electrical connector at fuel heater. Fuel
heater is located in top of fuel filter housing. Using ohmmeter, check
resistance between electrical terminals on fuel heater.
3) Resistance should be about one ohm when fuel is cold, and
about 1000 ohms when fuel is warm. Replace fuel heater if resistance
is not within specification.
NOTE: Fuel heater receives battery voltage from fuel heater relay.
Fuel heater relay is located in Power Distribution Center
(PDC), next to left battery. Refer to PDC lid for relay
location. For testing of fuel heater relay, see RELAYS under
RELAYS & SOLENOIDS. Consult wiring diagram for wiring circuit
testing. See appropriate wiring diagram in WIRING DIAGRAMS
article.
Fuel Transfer Pump Preliminary Inspection
1) Check for restricted or leaking fuel supply line to fuel
transfer pump or fuel return line located on driver's side of engine.
Repair fuel supply line or fuel return line if restricted or leaking.
2) Check for fuel leaking from weep hole on housing of fuel
transfer pump. Replace fuel transfer pump if fuel is leaking from weep
hole. Check fuel transfer pump for output pressure, pressure drop,
supply restriction, and air leaks.
NOTE: Separate pressure tests are necessary because transfer pump
operates at 2 pressure cycles, depending on whether engine is
running or cranking.

Fuel Transfer Pump Output Pressure
1) Remove 2 existing filter plug fittings at top of fuel
filter housing. Install 2 spring-loaded one-way check valve fittings
at inlet and outlet port. Install Fuel Pressure Test Gauge (6828) to
inlet port fitting. Prevent engine from starting by removing fuel
injection pump relay. Relay is located in Power Distribution Center
(PDC) next to left battery. Relay location is notated on PDC lid.
2) Crank engine while observing fuel pressure test gauge.
Fuel pressure should be 5-7 psi (0.35-0.49 kg/cm

). Reinstall fuel
system relay to PDC. Start engine. Fuel pressure should be minimum of
10 psi (0.7 kg/cm

). Because fuel injection pump relay was removed, a
Diagnostic Trouble Code (DTC) may have been set. Use DRB scan tool to
erase DTC. Go to PRESSURE DROP test.
Pressure Drop
Turn engine off. Remove Fuel Pressure Test Gauge (6828) from
inlet port and attach to outlet port. Start engine and note fuel
pressure. Pressure should not be more than 5 psi (0.35 kg/cm

) less
than inlet port pressure in Fuel Transfer Pump Outlet Pressure test.
See FUEL TRANSFER PUMP OUTPUT PRESSURE test. If fuel pressure is not
to specification, replace fuel filter. Go to FUEL SUPPLY RESTRICTION
test.
NOTE: Following test requires use of DRB scan tool and Periphal
Expansion Port (PEP) module. Ensure transfer pump pressure is\
okay before performing following test.
Fuel Supply Restriction
1) Disconnect fuel supply line quick-connect fitting at left
rear side of engine compartment. After disconnecting fuel line,
plastic clip will remain attached to metal fuel line at engine. Remove
clip from metal line. Snap clip into fuel supply hose. Install Rubber
Adapter Hose (6631) into ends of disconnected fuel supply line.
2) Install transducer from PEP module to brass "T" fitting on
rubber adapter hose. Connect DRB scan tool to transducer. Start engine
and record vacuum reading with engine speed at wide open throttle.
3) If vacuum reading is less than 6 in. Hg, check for
restriction in fuel supply line or fuel tank module. Repair fuel
supply line or module for restrictions as necessary. Also check fuel
pump inlet filter at bottom of module for obstructions. Go to AIR LEAK
IN FUEL SUPPLY LINE test.
NOTE: Following test requires use of a 3-foot section of 1/4" I.D.
clear tubing and 1/8" fitting.
Air Leak In Fuel Supply Line
1) Locate 2 test port plug fittings at top of fuel filter
housing. Clean fitting area. Remove test port fitting at fuel inlet
side of housing toward rear of filter housing. Install 1/8" fitting
with 1/4" O.D. nipple in place of test port. Clamp clear tubing to
fitting nipple. Place other end of hose into clear container.
2) To put fuel transfer pump into a 25 second run mode, turn
ignition switch to CRANK position, then release back to RUN position
without starting engine. Wait for air to purge from empty hose before
checking whether air bubbles are present. If bubbles are present,
check for leaks in supply line to fuel tank. If supply line is not
leaking, remove fuel tank module. Remove filter at bottom of module.
Check for leaks between supply nipple at top of module and filter
opening at bottom of module. Replace module as necessary.
Overflow Valve
1) Clean area around overflow valve and fuel return line at
injection pump. Remove overflow valve from pump and banjo fitting.

Remove and discard gaskets. Using blow gun with regulated pressure of
about 14-16 psi (0.9-1.1 kg/cm
), apply pressure to overflow valve
inlet end (injection pump side). If internal check valve releases and
air passes through valve, go to next step. If internal check valve
does not release and air does not pass through valve, replace valve.
2) Reduce air pressure to 10 psi (0.7 kg/cm

) and recheck
valve. If valve stays closed, valve is okay. If valve does not stay
closed, replace valve and gaskets.
Fuel Injection Pump
1) Ensure fuel transfer pump output pressure is within
specification before condemning fuel injection pump. See FUEL TRANSFER
PUMP OUTPUT PRESSURE. No mechanical adjustments are needed for fuel
injection timing. All timing and fuel adjustments are made by Engine
Control Module (ECM). If a DTC has been stored indicating an ENGINE
SYNC ERROR or STATIC TIMING ERROR, remove plastic access cover,
injection pump nut and washer.
2) Locate keyway behind washer. Ensure keyway aligning fuel
injection pump shaft to injection pump gear is in correct position and
pump gear has not slipped on pump shaft. Remove timing gear cover to
access timing gears. See 5.9L (24-VALVE) 6-CYLINDER DIESEL article in
ENGINES section. Use a "T" puller and separate injection pump gear
from pump shaft. Ensure keyway is installed with arrow toward rear of
pump.
NOTE: Pump timing is calibrated to pump keyway. Ensure 3-digit
number on pump keyway matches 3-digit number on fuel
injection pump data plate on side of injection pump.
See Fig. 6.
3) Ensure timing marks on crank, camshaft and pump align.
Align gears as necessary. After repair, erase DTC.
Fig. 6: Locating Fuel System Components
Courtesy of Chrysler Corp.
FUEL CONTROL

NOTE: A leaking fuel injector or high-pressure fuel line may cause
a rough idle, Black smoke, poor engine performance, poor fuel
economy and fuel knock. Following procedure is for
determining if fuel injector is defective.
WARNING: DO NOT allow diesel fuel to contact hot engine when checking
fuel injector, as high exhaust temperatures could cause a
fire. Use care when working around high-pressure fuel lines,
as fuel is under extreme pressure and could penetrate skin,
causing personal injury. Wear safety goggles and protective
clothing when checking fuel injectors.
Fuel Injector
1) Since a leaking high-pressure fuel line may cause the same
symptoms, check for leaking high-pressure fuel line before checking
fuel injector. To check for a leaking high-pressure fuel line, start
engine and allow engine to idle.
2) Inspect high-pressure fuel lines and connections for signs
of fuel leakage by placing cardboard over high-pressure fuel line and
connection. Note if leak is being detected by fuel being sprayed onto
cardboard. If leak exists, repair leak by tightening high-pressure
fuel line nut to 18 ft. lbs. (24 N.m) or replacing high-pressure fuel
line as necessary. If high-pressure fuel line is replaced, bleed air
from fuel system. See FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL,
OVERHAUL & INSTALLATION article.
3) To check for defective fuel injector, start and idle
engine. Loosen high-pressure fuel line nut at fuel injector and listen
for a decrease in engine speed. Tighten high-pressure fuel line nut to
18 ft. lbs. (24 N.m).
4) If fuel injector is operating properly, engine idle speed
should decrease when high-pressure fuel line nut is loosened. Repeat
procedure on each fuel injector.
5) If engine idle speed does not decrease, fuel injector is
defective and should be removed and tested with a diesel fuel injector
tester. Replace fuel injector if fuel injector opening (pop) pressure
is not about 4500 psi (316 kg/cm

).
EMISSION SYSTEMS & SUB-SYSTEMS
INTAKE MANIFOLD AIR HEATER SYSTEM
Intake Manifold Air Heater Preheat/Postheat Cycle
For testing information on intake manifold air heater system,
see DTC P0380: INTAKE AIR HEATER RELAY NO. 1 CONTROL CIRCUIT and DTC
P0382: INTAKE AIR HEATER RELAY NO. 2 CONTROL CIRCUIT tests in SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
MISCELLANEOUS CONTROLS
NOTE: Although some controlled devices listed here are not
technically engine performance components, they can affect
driveability if they malfunction.
TRANSMISSION
Park/Neutral Switch (A/T Models)
Park/neutral switch is mounted on transmission case, near
shift lever and contains a 3-pin connector. If problem exists in
park/neutral switch or wiring circuit, a Diagnostic Trouble Code (DTC)\
will be stored in Powertrain Control Module (PCM). See DTC P1899: P/N
SWITCH STUCK IN PARK OR IN GEAR test in SELF-DIAGNOSTICS - JEEP,

TRUCKS & RWD VANS article.
Transmission Governor Pressure Sensor (A/T Models)
Transmission governor pressure sensor is located on
transmission valve body. If problem exists in transmission governor
pressure sensor or wiring circuit, a Diagnostic Trouble Code (DTC)
will be stored in Powertrain Control Module (PCM). See appropriate
governor pressure sensor test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD
VANS article.
Transmission Overdrive Solenoid (A/T Models)
Transmission overdrive solenoid may also be referred to as
overdrive solenoid or 3-4 solenoid. Transmission overdrive solenoid is
located transmission valve body. If problem exists in transmission
overdrive solenoid or wiring circuit, a Diagnostic Trouble Code (DTC)
will be stored in Powertrain Control Module (PCM). See DTC P1740: TCC
OR O/D SOLENOID PERFORMANCE test in SELF-DIAGNOSTICS - JEEP, TRUCKS &
RWD VANS article.
Transmission Relay (A/T Models)
See RELAYS under RELAYS & SOLENOIDS.
Transmission Speed Sensor (A/T Models)
Transmission speed sensor may also be referred to as
transmission output shaft speed sensor. Transmission speed sensor is
located on overdrive case at rear of transmission. Transmission speed
sensor contains a 2-pin connector with a Dark Blue/Black wire and a
Light Green/Black wire. If problem exists in transmission speed sensor
or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in
Powertrain Control Module (PCM). See DTC P0720: LOW OUTPUT SPEED
SENSOR RPM, ABOVE 15 MPH test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD
VANS article.
Transmission Temperature Sensor (A/T Models)
Transmission temperature sensor is incorporated into governor
pressure sensor on transmission valve body. If problem exists in
transmission temperature sensor or wiring circuit, a Diagnostic
Trouble Code (DTC) will be stored in Powertrain Control Module (PCM)\
.
See appropriate transmission temperature sensor test in SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Transmission Torque Converter Clutch Solenoid (A/T Models)
The transmission Torque Converter Clutch (TCC) solenoid is
located on transmission valve body. If problem exists in TCC solenoid
or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in
Powertrain Control Module (PCM). See DTC P0743: TORQUE CONVERTER
CLUTCH SOLENOID/TRANSMISSION RELAY CIRCUIT test in SELF-DIAGNOSTICS -
JEEP, TRUCKS & RWD VANS article.


I - S YSTE M /C O M PO NEN T T E STS - R W D - G ASO LIN E

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - System & Component Testing - Trucks & RWD Vans - Gas
Dodge: Dakota, Durango, Ram Pickup, Ram Van, Ram Wagon
Jeep Cherokee, Grand Cherokee, Wrangler
INTRODUCTION
Before testing individual components or systems, perform
procedures in BASIC DIAGNOSTIC PROCEDURES - TRUCKS & RWD VANS -
GASOLINE article. Since many computer controlled and monitored
components set a fault message if they malfunction, also perform
procedures in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
NOTE: Testing of individual components does not isolate possible
shorts or opens in wiring harness of electronically
controlled systems. Perform all voltage tests using a Digital
Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance\
unless otherwise instructed in procedure. Use an ohmmeter to
isolate wiring harness shorts or opens.
COMPUTERIZED ENGINE CONTROLS
POWERTRAIN CONTROL MODULE (PCM)
PCM power and ground circuits may be checked by performing
TEST NS-1 in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article. For
PCM location, see PCM LOCATION table.
PCM LOCATION









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Application Location
Dakota & Durango ................. Right Front Fender, Near Firewall
Ram Pickup, Ram Van & Ram Wagon ...... On Firewall, Near Wiper Motor









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ENGINE SENSORS, SOLENOIDS & SWITCHES
SENSORS
Camshaft Position (CMP) Sensor
See appropriate DTC P0340: NO CAM SIGNAL AT PCM test in SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Crankshaft Position (CKP) Sensor
See appropriate DTC P0320: NO CRANK REFERENCE SIGNAL AT PCM
test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Engine Coolant Temperature (ECT) Sensor
See appropriate DTC P0117: ECT SENSOR VOLTAGE TOO LOW and DTC
P0118: ECT SENSOR VOLTAGE TOO HIGH tests in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
Heated Oxygen Sensor (HO2S)
See appropriate DTC for oxygen sensor in SELF-DIAGNOSTICS -
JEEP, TRUCKS & RWD VANS article.