SC HED ULE D S ER VIC ES
INSPECT
Exhaust System
Brake Hoses
Engine Coolant Level, Hoses & Clamps
Engine Air Cleaner & Air Pump Filters
Brake Linings
SERVICE
Lubricate Steering Linkage
Automatic Transmission Bands
Clean EGR Passages (5.9L)
REPLACE
Engine Oil
Engine Oil Filter (
1)
Automatic Transmission Fluid & Filter
Rear Axle Fluid
Front Axle Fluid (4x4)
Spark Plugs
Ignition Cables
PCV Valve (5.9L)
EGR Valve (5.9L)
Distributor Cap & Rotor (5.9L)
(
1) 8.0L: Change oil filter at every oil change.
5.9L: If mileage is less than 6,000 miles (9,600 Km) Yearly,
replace the oil filter at every oil change.
LUBRICATION SPECIFICATIONS
Material Condition Specification
Engine Oil Ambient Temperature Above 0 F SAE 10W-30
(
1) (-18 C) To Over 100 F (38 C)
Ambient Temperature Less Than SAE 5W-30
-20 F (-29 C) Up To 32 F (0 C)
Engine All 50/50 Mixture Of
Coolant Distilled Water &
Ethylene Glycol
Brake Fluid All DOT 3
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.
manifold, sends input signal to Engine Control Module (ECM). ECM uses
input signal for controlling fuel control, timing and engine
protection. ECM will lower engine power if boost is too high.
Oil Pressure Sensor
Oil pressure sensor signal is input to Engine Control Module
(ECM). ECM converts signal to pressure value. Value is sent on CCD Bus\
to instrument panel gauge/light. Oil pressure sensor is located on
side of engine block, below ECM. See Fig. 2.
Power Take Off (PTO)
This input is used on vehicles equipped with a Power Take Off
(PTO) unit. When PTO is engaged, Engine Control Module (ECM) will
disable some OBD-II functions.
Water-In-Fuel (WIF) Sensor
WIF sensor is located in bottom of fuel filter/water
separator. See Fig. 2. WIF sensor delivers input signal to Engine
Control Module (ECM) when water exists in the fuel filter/water
separator. As water level increases, resistance across WIF sensor
decreases. ECM compares decrease in resistance to a high water
standard value. When resistance is 30,000-40,000 ohms, ECM will turn
on WATER-IN-FUEL warning light. WATER-IN-FUEL warning light is located
on instrument panel, just below tachometer. ECM monitors input signal
when ignition switch is in the ON position and continues to monitor
input signal until intake manifold air heater post-heat cycle is
complete.
PCM INPUT SIGNALS
A/C Switch
When A/C switch is in ON position, an input signal is
delivered from A/C switch to Engine Control Module (ECM) to indicate
that A/C operation has been requested. Once A/C operation has been
requested, an A/C request signal is delivered to ECM from A/C high-
pressure switch and A/C low-pressure switch. The A/C request signal
indicates evaporator pressure is within proper range for A/C
operation. ECM uses A/C request signal to cycle A/C compressor clutch
by using an A/C clutch relay. A/C clutch relay may also be referred to
as A/C compressor clutch relay. If A/C high-pressure switch or A/C
low-pressure switch opens, A/C request signal will not be delivered to
the ECM. ECM will then open ground circuit for A/C clutch relay and
A/C compressor clutch will be disengaged.
The A/C clutch relay is located in power distribution center
at driver's side front corner of engine compartment, near the battery.
The A/C high-pressure switch is located on discharge line, near A/C
compressor. The A/C low-pressure switch is located on top of
accumulator.
Accelerator Pedal Position Sensor (APPS) Output From ECM
Accelerator Pedal Position Sensor (APPS) is mounted on top
left of engine. See Fig. 2. Sensor provides DC voltage input signal to
Engine Control Module (ECM) to indicate throttle position. On previous\
engines, there were linkages between accelerator pedal, throttle
position sensor and injection pump. On this engine, no linkage exists
between accelerator pedal and injection pump. APPS signal is sent on
CCD Bus circuit from ECM to PCM.
Automatic Shutdown (ASD) Relay
A 12-volt input signal is delivered from ASD relay to Engine
Control Module (ECM) when ASD relay is energized. If ECM does not
receive a 12-volt input signal when ASD relay is energized, a
Diagnostic Trouble Code (FTC) will be stored in ECM. ASD relay is
brakelines are attached to and is mounted in the engine compartment.
ECM OUTPUT SIGNALS
APPS & CKP Output To PCM
See ACCELERATOR PEDAL POSITION SENSOR (APPS) OUTPUT FROM ECM
under PCM INPUT SIGNALS.
CCD Bus
These circuits are connected between Engine Control Module
(ECM) and Powertrain Control Module (PCM) to allow communication
between modules.
DLC Output
Data Link Connector (DLC) is connected to Engine Control
Module (ECM). Using a scan tool, data can be retrieved (output) from\
ECM.
5-Volt Sensor Supply Output
Engine Control Module (ECM) supplies a 5-volt reference
signal to the following sensors:
* Crankshaft Position (CKP) Sensor
* Camshaft Position (CMP) Sensor
* Intake Air Temperature (IAT) Sensor
* Engine Oil Pressure Sensor
* Manifold Absolute Pressure (MAP) Sensor
Engine Control Module (ECM) also supplies voltage to the
following sensors:
* Accelerator Pedal Position Sensor (APPS)
* Intake Air Temperature (IAT) Sensor
* Engine Oil Pressure Sensor
* Engine Coolant Temperature (ECT) Sensor
* Manifold Absolute Pressure (MAP) Sensor
* Water-In-Fuel (WIF) Sensor
Fuel Injection Pump Relay
The Engine Control Module (ECM) energizes the fuel injection
pump and integral Fuel Pump Control Module (FPCM) through the relay.
When ignition is turned on, ECM supplies 12 volts to fuel injection
pump relay, located in Power Distribution Center.
Fuel Pump Control Module (FPCM)
Fuel Pump Control Module (FPCM) controls fuel pump using
inputs from Engine Control Module (ECM). FPCM is integral to top of
fuel pump. ECM and FPCM are interconnected together for fuel injection
control.
Fuel Transfer Pump
Engine Control Module (ECM) supplies power to fuel transfer
pump. Transfer fuel pump supplies fuel under low pressure (14 psi)
while engine is running to fuel injection pump. Fuel transfer pump
supplies an excess of fuel to cool fuel injection pump. Excess fuel is
returned to fuel tank by fuel injection pump.
Intake Manifold Air Heater Relays
Intake manifold air heater relays provide voltage to intake
manifold air heater for warming of intake. See Fig. 5. Warming of
intake air aids in engine starting and improved driveability during
cold ambient temperatures. Intake manifold air heater relays are
mounted on inner wheelwell, below driver's side battery. See Fig. 6.
converter lock-up. ECM uses various input signals such as transmission
temperature, output shaft speed, central module timer, engine speed,
APPS and brake switch position to determine operation of transmission
torque converter clutch solenoid. Transmission torque converter clutch
solenoid is located on transmission valve body.
FUEL SYSTEM
FUEL DELIVERY
Fuel Injection Pump
A camshaft-driven Bosch VP44 in-line fuel injection pump is
used to supply high pressure fuel to each fuel injector in precise
metered amounts at the correct time. See Fig. 2. The pump is timed to
camshaft gear. Pump output is controlled by integral Fuel Pump Control
Module (FPCM). Because of electronic control, idle speeds and pump
timing are not adjustable. See ON-VEHICLE ADJUSTMENTS - TRUCKS -
DIESEL article. FPCM can operate engine if crankshaft position sensor
signal does not exist. Fuel injection occurs near completion of
compression stroke for each cylinder.
Fuel injection pump contains an overflow valve which allows
excess fuel to return to the fuel tank. Overflow valve is located on
side of fuel injection pump and is used to attach the fuel return line
to the fuel injection pump.
Fuel Transfer Pump
Fuel transfer pump is located on driver's side of cylinder
block, above starter. See Fig. 2. A 12 volt, 12-amp electric vane-type
pump supplies low fuel pressure from fuel tank, through fuel
heater/fuel filter/water separator to fuel injection pump. Fuel
transfer pump contains internal check valves to prevent fuel from
bleeding back into fuel tank during engine shutdown. Pump will self
prime with ignition on for 2 seconds. Pump has 2 modes, 100 percent
duty cycle (10 psi) when engine is running and 25 percent duty cycle
(7 psi) when engine is cranking.
Fuel Filter/Water Separator
Fuel filter/water separator, located on left side of engine,
protects injection pump by removing water and contaminants from fuel.
See Fig. 2 . Assembly also includes fuel heater and Water-In-Fuel (WIF)
sensor.
In-Tank Fuel Filter
A separate in-tank fuel filter is attached to bottom of fuel
tank module. In-tank fuel filter does not require service under normal
conditions.
FUEL CONTROL
Fuel Injector
Fuel injector delivers atomized fuel into the cylinder.
During fuel injection, fuel pressure from fuel injection pump
increases to fuel injector opening pressure or pop pressure of 4500
psi (316 kg/cm
). This is the pressure required to lift fuel injector
needle valve from its seat, allowing fuel to be injected into the
cylinder. Once fuel pressure decreases to less then the opening
pressure, a spring forces needle valve closed and stops fuel injection
into the cylinders. Each fuel injector is connected to injection pump
by a high pressure (as much as 17,405 psi) line.
Fuel Injection Timing
Pump output is controlled by integral Fuel Pump Control
Module (FPCM). Because of electronic control, pump timing is not
adjustable. See ON-VEHICLE ADJUSTMENTS - TRUCKS - DIESEL article.
FUEL FILTER/WATER SEPARATOR
Fuel filter/water separator is located on left side of engine
and contains fuel heater, Water-In-Fuel (WIF) sensor and drain valve.
See Fig. 2 . The WIF sensor delivers an input signal to Engine Control
Module (ECM) when water exists in fuel filter/water separator. ECM
will then turn on WATER-IN-FUEL warning light. WATER-IN-FUEL warning
light is located on instrument panel, just below tachometer. The
WATER-IN-FUEL warning light informs the operator to drain water from
fuel filter/water separator to prevent damage to fuel system
components. Water may be drained from fuel filter/water separator by
using drain valve on fuel filter/water separator.
FUEL HEATER
Fuel heater is used to prevent diesel fuel from waxing during
cold temperatures. Fuel heater is located in fuel filter/water
separator. See Fig. 2. Fuel flows from fuel tank to fuel transfer pump
and then to fuel filter/water separator. Fuel heater contains a fuel
heater temperature sensor that senses the fuel temperature. When
temperature is less than 37-53
F (3-12 C), fuel heater temperature
sensor allows current to flow to the fuel heater to warm the fuel.
When temperature is more than 67-83
F (19-28 C), fuel heater
temperature sensor turns off the current flow to the fuel heater.
Voltage to operate fuel heater is provided from ignition switch,
through fuel heater relay and to fuel heater. Fuel heater and fuel
heater relay are not controlled by Engine Control Module (ECM).
EMISSION SYSTEMS
INTAKE MANIFOLD AIR HEATER SYSTEM
Intake manifold air heater is used to warm intake air during
cold starting conditions. Heater system consists of 2 relays and 2
grid heaters installed on top of intake manifold. See Fig. 5.
Engine Control Module (ECM) energizes intake manifold air
heater relays to provide voltage to intake manifold air heater before
and after starting depending on input signals from intake manifold air
temperature sensor, engine speed sensor and vehicle speed. Intake
manifold air heater relays are not energized when intake manifold air
temperature is greater than 59
F (15 C) or during engine cranking.
Intake manifold air heater relays are mounted on left inner wheelwell,
below left side battery. See Fig. 6.
Intake manifold air temperature sensor monitors intake
manifold air temperature and delivers an input signal to ECM for
controlling intake manifold air heater. Intake manifold air
temperature sensor is located in intake manifold. See Figs. 2 and 4.
SELF-DIAGNOSTIC SYSTEM
DATA LINK CONNECTOR
The Data Link Connector (DLC) is a 16-pin connector located
at lower edge of driver's side of instrument panel, just above the
accelerator pedal. The Engine Control Module (ECM) contains a self-
diagnostic system which stores a Diagnostic Trouble Code (FTC) if an
incorrect signal or no signal is received from certain sensors or
components. FTC may be retrieved from ECM for system diagnosis by