1999 DODGE RAM check engine

Fig. 6: Locating Intake Manifold Air Heater Relays
Courtesy of Chrysler Corp.
Malfunction Indicator Light (MIL)
The MIL is located on the instrument panel, just below
tachometer and may also be referred to as the CHECK ENGINE light. MIL
comes on for a short period and then goes off as a bulb and wiring
circuit test each time ignition switch is turned to the ON position.
If Engine Control Module (ECM) receives an incorrect signal or
receives no signal from certain sensors or components, ECM will turn
on the MIL to warn the driver that a malfunction exists in the
electronic system.
Oil Pressure Gauge/Warning Light
Oil pressure gauge/warning light output from Engine Control
Module (ECM) to instrument cluster is routed on CCD Bus circuit.

signal to the transmission solenoid assembly for transmission
temperature sensor.
Generator Field
Engine Control Module (ECM) provides output signals to
generator field for regulating charging system voltage at 12.9-15.0
volts. ECM contains an internal electronic voltage regulator for
controlling the charging system voltage.
Generator Light
If Engine Control Module (ECM) senses a low charging system
condition, generator light on instrument panel (if equipped) will be
turned on. Generator light may also come on momentarily at low idle
speed when all accessories are on.
Malfunction Indicator Light (MIL)
The MIL is located on the instrument panel, just below
tachometer and may also be referred to as the CHECK ENGINE light. MIL
comes on for a short period and then goes off as a bulb and wiring
circuit test each time ignition switch is turned to the ON position.
If Engine Control Module (ECM) receives an incorrect signal or
receives no signal from certain sensors or components, ECM will turn
on the MIL to warn the driver that a malfunction exists in the
electronic system.
Overdrive Indicator Light (A/T Models)
Engine Control Module (ECM) delivers output signal to operate\
transmission overdrive indicator (O/D OFF) light in accordance with
position of the transmission overdrive switch. If overdrive is turned
off with transmission overdrive switch, transmission overdrive
indicator light will be turned on. Transmission overdrive indicator
light is located on instrument panel, just below the speedometer.
Tachometer
Engine Control Module (ECM) delivers output signal to operate\
tachometer on instrument panel to indicate engine RPM.
Transmission Overdrive Solenoid (A/T Models)
Engine Control Module (ECM) delivers output signal to
transmission overdrive solenoid for controlling transmission overdrive
shifts. Transmission overdrive solenoid is located on transmission
valve body.
Transmission Relay (A/T Models)
Transmission relay may be referred to as transmission control
relay or transmission 12-volt supply relay. Transmission relay ground
circuit is controlled by the Engine Control Module (ECM). When ground
circuit is completed, transmission relay supplies voltage to solenoid
assembly on the transmission. Transmission relay is located in power
distribution center at driver's side front corner of engine
compartment, near the battery.
Transmission Temperature Warning Light (A/T Models With
Heavy-Duty Transmission)
Engine Control Module (ECM) delivers output signal to turn on\
transmission temperature warning light if transmission fluid
temperature is determined to be greater than 280
F (138C) by the
transmission temperature sensor. Transmission temperature warning
light is located on instrument panel, just below the tachometer.
Transmission Torque Converter Clutch Solenoid (A/T Models)
Engine Control Module (ECM) delivers an output signal to
operate transmission torque converter clutch solenoid for torque

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

using DLC and a scan tool. The DLC also provides a means to
communicate with various vehicle control modules, check system
operating conditions and to operate various system components.
MALFUNCTION INDICATOR LIGHT (MIL)
The MIL is located on the instrument panel, just below
tachometer and may also be referred to as the CHECK ENGINE light. MIL
comes on for a short period and then goes off as a bulb and wiring
circuit test each time ignition switch is turned to the ON position.
If Engine Control Module (ECM) receives an incorrect signal or
receives no signal from certain sensors or components, ECM will turn
on the MIL to warn the driver that a malfunction exists in the
electronic system.
MISCELLANEOUS CONTROLS
TRANSMISSION
Transmission Overdrive Solenoid (A/T Models)
Engine Control Module (ECM) operates transmission overdrive
solenoid for controlling transmission overdrive shifts. Transmission
overdrive solenoid is located on transmission valve body.
Transmission Torque Converter Clutch Solenoid (A/T Models)
Engine Control Module (ECM) operates transmission torque
converter clutch solenoid for torque 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. Torque converter clutch solenoid is located on
transmission valve body.

various switch input operations to adjust IAC motor to obtain optimum
idle conditions. Deceleration stall is prevented by increasing airflow
when throttle is closed suddenly.
IGNITION SYSTEM
NOTE: Pickup equipped with 8.0L engine uses Distributorless
Ignition system (DIS). All other models use a Hall Effect
ignition system.
The PCM completely controls ignition system. During
crank/start mode, PCM will set a fixed amount of spark advance for an
efficient engine start. Amount of spark advance or retard is
determined by inputs that PCM receives from ECT sensor, engine vacuum
and engine RPM. During engine operation, PCM can supply an infinite
number of advance curves to ensure proper engine operation.
DISTRIBUTORLESS IGNITION SYSTEM (DIS)
DIS eliminates mechanical ignition components that can wear
out. PCM has complete ignition control and uses a coil pack, CMP
sensor and CKP sensor to control ignition timing. CMP sensor reads
slots in cam timing sprocket. PCM uses this information along with
information from CKP sensor to determine if fuel injectors and
ignition coils are properly sequenced for correct cylinders.
Basic timing is determined by CKP sensor position and is not
adjustable. One complete engine revolution may be required for PCM to
determine crankshaft position during cranking.
Molded ignition coils are used. Each coil fires 2 paired
spark plugs at the same time. One cylinder is on compression stroke
and other cylinder is on exhaust stroke.
HALL EFFECT IGNITION SYSTEM
This system is equipped with a Hall Effect distributor. See
Fig. 1 . Shutter(s) attached to distributor shaft rotate through
distributor Hall Effect switch, also referred to as a CMP sensor,
which contains a distributor pick-up (a Hall Effect device and
magnet). As shutter blade(s) pass through pick-up, magnetic field is
interrupted and voltage is toggled between high and low. PCM uses this
cylinder position data from CMP sensor, along with engine speed (RPM)
and CKP sensor data, to control ignition timing and injector pulse
width to maintain optimum driveability.
EMISSION SYSTEMS
Vehicles are equipped with different combinations of emission
system components. Not all components are used on all models. To
determine component usage on a specific model, see EMISSION
APPLICATIONS - TRUCKS article.
AIR INJECTION SYSTEM
This system adds a controlled amount of air to exhaust gases,
through air relief valve and check valves, to assist oxidation of
hydrocarbons and carbon monoxide in exhaust stream. Air is injected at
catalytic converters.
CRANKCASE VENTILATION (CCV) SYSTEM
CCV system performs same function as a conventional Positive

Fig. 2: Identifying Oil Pan Gasket (36RH, 46RE & 47RE)
LUBRICATION
SERVICE INTERVALS
Transmission
Check transmission fluid level when performing other
underhood services. Under normal service conditions or severe service
conditions change transmission fluid, adjust bands and replace
transmission filter at specified interval. See TRANSMISSION SERVICING
INTERVALS table. Severe service conditions are conditions such as long
periods of engine idling, trailer towing, off-highway operation, snow
removal, or operating in dusty or excessively hot conditions.
TRANSMISSION SERVICING INTERVALS









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Application Months Miles
Dakota & Durango
Normal Service ........................ 30 .............. 37,500
Severe Service ........................ ( 1) ............. 12,000

Ram Pickup
Gasoline Models
Light-Duty (2)
Normal Service ..................... 30 .............. 37,500
Severe Service ..................... ( 1) ............. 12,000
Medium-Duty & Heavy-Duty
Normal Service ..................... 24 .............. 24,000
Severe Service ..................... ( 1) ............. 12,000
Diesel Models
Normal Service ....................... 24 .............. 24,000
Severe Service ....................... ( 1) ............. 12,000
Ram Van/Wagon
Normal Service ........................ ( 3) ................ ( 3)
Severe Service ........................ ( 1) ............. 12,000
( 1) - Monthly interval is not available from manufacturer.
( 2) - Light-duty applies to all 1500 models and 2500 models except
5.9L diesel or 8.0L engines. Medium-duty applies to 2500 and
3500 California models with 8.0L engine. Heavy-duty applies to
2500 and 3500 Federal models with 8.0L engine and all 3500
models with 5.9L gasoline engine.
( 3) - Normal service interval is not available from manufacturer.









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Transfer Case
Check transfer case fluid level when performing other
underhood services. Under normal service conditions or severe service
conditions change transfer case fluid at specified interval. See
TRANSFER CASE SERVICING INTERVALS table. Severe service conditions are
conditions such as long periods of engine idling, trailer towing, off-
highway operation, snow removal, or operating in dusty or excessively
hot conditions.
TRANSFER CASE SERVICING INTERVALS









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Application Months Miles
Dakota
Normal Service ....................... 30 ............... 37,500
Severe Service ....................... ( 1) .............. 36,000
Ram Pickup
Gasoline Models
Light-Duty ( 2)
Normal Service .................... 30 ............... 37,500
Severe Service .................... ( 1) .............. 36,000
Medium-Duty & Heavy-Duty
Normal Service .................... 36 ............... 36,000
Severe Service .................... ( 1) .............. 36,000
Diesel Models
Normal Service ...................... 36 ............... 36,000
Severe Service ...................... ( 1) .............. 36,000
( 1) - Monthly interval is not available from manufacturer.
( 2) - Light-duty applies to all 1500 models and 2500 models except
5.9L diesel or 8.0L engines. Medium-duty applies to 2500 and
3500 California models with 8.0L engine. Heavy-duty applies to
2500 and 3500 Federal models with 8.0L engine and all 3500
models with 5.9L gasoline engine.









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Power Take-Off (PTO) Adapter (Ram Pickup 2WD 2500 & 3500)
Check PTO adapter fluid level when performing other underhood
services. Service interval is not available from manufacturer.

CHECKING FLUID LEVEL
Transmission
1) Drive vehicle until engine and transmission are at normal
operating temperature. Park vehicle on level surface. Apply parking
brake.
2) With engine idling, move shift lever through all gear
ranges, ending in Neutral. Check fluid level. Fluid level should be at
the MAX arrow mark area on dipstick with transmission fluid
temperature at 180
F (82C). Add appropriate type of transmission
fluid if necessary. See RECOMMENDED FLUID. DO NOT overfill
transmission.
Transfer Case
Park vehicle on level surface. Remove transfer case fill plug
from rear of transfer case. Fluid level should even with bottom of
transfer case fill plug hole on rear of transfer case. Add appropriate
type of transfer case fluid if necessary. See RECOMMENDED FLUID.
Install and tighten transfer case fill plug to specification. See
TORQUE SPECIFICATIONS.
Power Take-Off (PTO) Adapter (Ram Pickup 2WD 2500 & 3500)
Park vehicle on level surface. Remove fill plug from rear of
PTO adapter. See Fig. 3. Fluid level should even with bottom of fill
plug hole on rear of PTO adapter. Add appropriate type of fluid if
necessary. See RECOMMENDED FLUID. Install and tighten fill plug to
specification. See TORQUE SPECIFICATIONS.
Fig. 3: Locating Fill Plug & Drain Plug On PTO Adapter (Ram
Pickup 2WD 2500 & 3500)
Courtesy of Chrysler Corp.
RECOMMENDED FLUID