1999 DODGE RAM low oil pressure

Stud loose in
taper hole ............. A ........... (7) Require repair or
replacement.
Taper hole elongated .... A ........ ( 8) Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ........ ( 7) Require replacement.
Wear exceeds
manufacturer's
specifications .......... B ............ Require replacement.
( 1) - If greaseable, grease joint. If problem persists or
joint is non-greaseable, require replacement.
( 2) - Cracked grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 3) - Lack of grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 4) - Torn grease boot will allow contaminants to enter the
joint and will accelerate wear.
( 5) - If manufacturer's procedures for inspection exist, use
those procedures; otherwise, use an approved inspection
method such as the dry park check.
CAUTION: DO NOT use pliers or pry bar to check ball and
socket movement. Use only moderate hand pressure.
( 6) - Excessive looseness is defined as being significant
enough to affect vehicle handling or structural
integrity.
( 7) - Check for damaged taper hole.
( 8) - Check for damaged stud.









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SHOCK ABSORBERS, STRUT CARTRIDGES AND STRUT ASSEMBLIES
You are not required to replace shocks or struts in axle
sets. However, when replacing a shock or strut due to the conditions
that follow, you may suggest replacement of the other shock or strut
on the same axle for improved performance and preventive maintenance.
* Part is close to the end of its useful life
* To extend tire life
* To balance ride and handling
* To improve stopping distance
When replacing steering and/or suspension components which
may affect an alignment angle, you are required to check and adjust
alignment as needed. Refer to the OEM specifications.
Under no circumstances should a technician bend struts or
strut housings.
A vehicle's load-carrying and handling abilities are limited
by its suspension, tires, brakes, and driveline. Installing coil over
shocks or any other load assist device does not increase the vehicle's
load capacity. See the vehicle owner's manual for more details.
NOTE: If vehicle is equipped with original equipment coil over
shocks, apply the conditions for coil springs from the
SPRINGS - COIL, LEAF AND TORSION BAR section of the
STEERING AND SUSPENSION guidelines. If the vehicle is
equipped with add-on coil over shocks, you may suggest
replacing the shocks with standard shocks for any spring-
related condition.
SHOCK ABSORBER, STRUT CARTRIDGE AND STRUT ASSEMBLY INSPECTION









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Stud loose in
taper hole ............. A ........... (7) Require repair or
replacement.
Taper hole elongated .... A ........ ( 8) Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ........ ( 7) Require replacement.
Wear exceeds
manufacturer's
specifications .......... B ............ Require replacement.
( 1) - If greaseable, grease joint. If problem persists or
joint is non-greaseable, require replacement.
( 2) - Cracked grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 3) - Lack of grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 4) - Torn grease boot will allow contaminants to enter the
joint and will accelerate wear.
( 5) - If manufacturer's procedures for inspection exist, use
those procedures; otherwise, use an approved inspection
method such as the dry park check.
CAUTION: DO NOT use pliers or pry bar to check ball and
socket movement. Use only moderate hand pressure.
( 6) - Excessive looseness is defined as being significant
enough to affect vehicle handling or structural
integrity.
( 7) - Check for damaged taper hole.
( 8) - Check for damaged stud.









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SHOCK ABSORBERS, STRUT CARTRIDGES AND STRUT ASSEMBLIES
You are not required to replace shocks or struts in axle
sets. However, when replacing a shock or strut due to the conditions
that follow, you may suggest replacement of the other shock or strut
on the same axle for improved performance and preventive maintenance.
* Part is close to the end of its useful life
* To extend tire life
* To balance ride and handling
* To improve stopping distance
When replacing steering and/or suspension components which
may affect an alignment angle, you are required to check and adjust
alignment as needed. Refer to the OEM specifications.
Under no circumstances should a technician bend struts or
strut housings.
A vehicle's load-carrying and handling abilities are limited
by its suspension, tires, brakes, and driveline. Installing coil over
shocks or any other load assist device does not increase the vehicle's
load capacity. See the vehicle owner's manual for more details.
NOTE: If vehicle is equipped with original equipment coil over
shocks, apply the conditions for coil springs from the
SPRINGS - COIL, LEAF AND TORSION BAR section of the
STEERING AND SUSPENSION guidelines. If the vehicle is
equipped with add-on coil over shocks, you may suggest
replacing the shocks with standard shocks for any spring-
related condition.
SHOCK ABSORBER, STRUT CARTRIDGE AND STRUT ASSEMBLY INSPECTION









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article.
POSITIVE CRANKCASE VENTILATION (PCV)
PCV Valve
1) With engine running at curb idle, remove PCV valve from
grommet. If valve is functioning properly, a hissing sound will be
heard as air passes through valve.
2) With engine running, place finger over valve inlet. Strong
vacuum should be felt at valve inlet. Stop engine. Remove and shake
PCV valve to ensure a metallic clicking noise can be heard, indicating
valve is free. Reinstall PCV valve.
3) Remove crankcase ventilation filter or oil filler cap from
valve cover. Hold a piece of stiff paper over opening. After allowing
about one minute for crankcase pressure stabilization, paper should be
drawn against opening.
4) If paper is held against opening, performance is okay. If
paper is not held against opening, replace PCV valve and retest. If
performance does not improve, inspect system for restrictions and
clean as necessary.
MISCELLANEOUS CONTROLS
NOTE: Although the controlled devices listed here are not
technically engine performance components, they can affect
driveability if they malfunction.
RELAYS
A/C Clutch Relay
See A/C CLUTCH RELAY under RELAYS.
Radiator Fan Control Relay
See RADIATOR FAN CONTROL RELAY under RELAYS.
Torque Converter Clutch (TCC) Relay
See TORQUE CONVERTER CLUTCH (TCC) RELAY under RELAYS
Transmission Governor Pressure Solenoid Relay
See TRANSMISSION GOVERNOR PRESSURE SOLENOID RELAY under
RELAYS.
Transmission 12-Volt Supply Relay
See TRANSMISSION 12-VOLT SUPPLY RELAY under RELAYS.
Vehicle Speed Control Relay
See VEHICLE SPEED CONTROL RELAY under RELAYS.

NOTE: Turbocharger is not serviceable and must be replaced as a
complete assembly. Turbocharger overhaul procedures should
only be performed by an authorized facility.
Turbocharger is mounted on exhaust manifold. See Fig. 1.
Exhaust gases rotate turbine wheel along with the shaft and compressor
wheel. Rotating of compressor wheel forces an increased amount of
airflow (boost pressure) through intercooler and then into intake
manifold where the air is distributed into each cylinder. Supplying
increased airflow provides improved engine performance, lower exhaust
smoke density, altitude compensation and reduced engine noise.
Turbocharger contains a wastegate which is used for controlling boost
pressure at high speeds. Turbocharger is lubricated by pressurized
engine oil from engine oiling system. Excess engine oil is returned
through turbocharger oil return line into the cylinder block.
Fig. 2: Locating Fuel System & Various Engine Components
Courtesy of Chrysler Corp.
COMPUTERIZED ENGINE CONTROLS

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.

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.

drive plate. PCM uses this information to determine fuel injection
sequence, ignition signal and spark timing.
Cruise Control Switch
Cruise control switch provides PCM with 3 separate inputs.
ON/OFF switch input informs PCM that cruise control system has been
activated. SET/COAST switch input informs PCM that set vehicle speed
has been selected, or if depressed will decelerate until switch is
released. RESUME/ACCEL switch input informs PCM that a previously set
speed has been selected or, if depressed, will increase speed until
released. PCM uses these inputs to control cruise control servo.
Engine Coolant Temperature (ECT) Sensor
ECT sensor monitors engine coolant temperature. PCM uses ECT
sensor information to adjust air/fuel mixture and idle speed and to
control radiator cooling fans as necessary.
Fuel Level Sensor
PCM supplies a 5-volt reference signal to fuel module in gas
tank. Fuel level sensor sends a signal to PCM indicating fuel level.
PCM monitors this signal to prevent a false misfire signal if fuel
level is less than 15 percent. PCM also sends this signal to fuel
gauge.
Heated Oxygen Sensor (HO2S)
HO2S produces a small electrical voltage (0-1 volt) when
exposed to heated exhaust gas. HO2S is electrically heated for faster
warm-up. Heating element is powered through Auto Shutdown (ASD) relay.\
HO2S acts like a rich/lean (air/fuel ratio) switch by
monitoring oxygen content in exhaust gas. This information is used by
PCM to adjust air/fuel ratio by adjusting injector pulse width.
HO2S produces low voltage when oxygen content in exhaust gas
is high. When oxygen content in exhaust gas is low, HO2S produces a
higher voltage.
Ignition Switch
Ignition switch sends signal to PCM indicating whether switch
is on, off or cranking (ST). When PCM receives ON signal, it energizes\
ASD relay coil and supplies power to sensors and actuators. When PCM
receives ST signal, it controls fuel injection rate, idle speed,
ignition timing, etc. for optimum cranking conditions.
Intake Air Temperature (IAT) Sensor
IAT sensor measures temperature of incoming intake air. This
information is used by PCM to adjust air/fuel mixture.
Manifold Absolute Pressure (MAP) Sensor
MAP sensor monitors intake manifold vacuum. Sensor transmits
information on manifold vacuum and barometric pressure to PCM. MAP
sensor information is used with information from other sensors to
adjust air/fuel mixture.
Oil Pressure Sensor
Sensor sends a signal to PCM to indicate oil pressure.
Park/Neutral (P/N) Switch (A/T Models)
This switch may also be referred to as a Park/Neutral
Position (PNP) switch. P/N switch is available on vehicles equipped
with A/T only. Switch prevents engine starter from engaging if vehicle
is in any gear except Park or Neutral.
P/N switch input (varied with gear selection) is used to
determine idle speed, fuel injector pulse and ignition timing.