1999 DODGE RAM catalytic converter

1 - Part is close to the end of its useful life (just above
discard specifications, or weak; failure likely to occur
soon, etc.)
2 - To address a customer need, convenience, or request (to
stiffen ride, enhance performance, eliminate noise,
etc.)
3 - To comply with maintenance recommended by the vehicle's
Original Equipment Manufacturer (OEM)
4 - Technician's recommendation based on substantial and
informed experience
NOTE: Suggested services are always optional. When presenting
suggested repairs to the customer, you must present
the facts, allowing the customer to draw their own
conclusions and make an informed decision about how to
proceed.
EXHAUST
SERVICE PROCEDURES REQUIRED AND SUGGESTED FOR PROPER
VEHICLE OPERATION
WARNING: Federal EPA rules prohibit altering an exhaust system in
any way that defeats the emission reduction components of a
vehicle. Be sure to review and adhere to EPA policy on
removing and replacing catalytic converters. Where state or
local laws are stricter, they take precedence over these
guidelines.
NOTE: Some exhaust systems are of a welded design. It is not
required that the entire system be replaced. Determine the
need to replace individual components based on conditions of
component.
CATALYTIC CONVERTERS
CAUTION: Before working on an exhaust system, review EPA
regulations on removing and replacing catalytic converters.
NOTE: Any time a converter has failed, further diagnosis is
required to determine the reason(s) for converter failure.
CATALYTIC CONVERTER INSPECTION









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Condition Code Procedure
Air injection tube
broken ................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
burnt .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
leaking ................ A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube

loose .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
restricted ............. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads damaged ........ A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads stripped
(threads missing) ...... A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Body cracked ............ B .. Require repair or replacement.
Converter empty ......... A .. Require repair or replacement.
Converter fill plug
missing ................ C .. Require repair or replacement.
Converter missing ....... C ............ Require replacement.
Exhaust gases leaking ... A .. Require repair or replacement.
Flanges leaking ......... A ... Require repair or replacement
of flanges.
Inlet pipes cracked ..... B .. Require repair or replacement.
Internal rattle (except
pellet-type) ........... 2 .......... (1) Further inspection
required.
Mounting brackets that
are part of converter
broken ................. A .. Require repair or replacement.
Obvious overheating ..... .. ......... ( 2) Require testing of
converter.
Outlet pipes cracked .... B .. Require repair or replacement.
Pieces of catalyst
material found
downstream ............. 1 ............ Suggest replacement.
Plugged ................. A ........ ( 3) Require replacement.
Testing has determined
that existing converter
has been lead-poisoned,
contaminated, or failed
testing ................ A .. Require repair or replacement.
( 1) - If the converter is breaking up, suggest converter
replacement. If an object has fallen into the converter,
remove the object.
( 2) - Overheating is caused by something other than the
converter. Further diagnosis is required to determine
the cause of the overheating.
( 3) - Determine cause and correct to ensure that new converter
will not become plugged.









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EXHAUST AND TAIL PIPES
NOTE: For pipes with resonators, also see MUFFLERS AND RESONATORS.
EXHAUST AND TAIL PIPE INSPECTION

been submerged in water. Water can enter through the axle
vent hole and contaminate the lubricant.
BATTERY WARNING
WARNING: When battery is disconnected, vehicles equipped with
computers may lose memory data. When battery power is
restored, driveability problems may exist on some vehicles.
These vehicles may require a relearn procedure.
WARNING: Batteries produce flammable hydrogen gas. Keep flames and
sparks away from the battery or and explosion may occur.
Never smoke when working in the vicinity of the battery.
WARNING: When checking or servicing the battery, disconnect the
negative cable. Be careful not to cause a short circuit by
allowing metal objects to contact the battery posts and the
vehicle at the same time.
REPLACING BLOWN FUSES
CAUTION: Before replacing a blown fuse, remove ignition key, turn off
all lights and accessories to avoid damaging the electrical
system. Be sure to use fuse with the correct indicated
amperage rating. The use of an incorrect amperage rating fuse
may result in a dangerous electrical system overload.
BRAKE PAD WEAR INDICATOR
Indicator will cause a squealing or scraping noise, warning
that brake pads need replacement.
BRAKE HOSES
WARNING: Worn brake hoses can burst and cause brake failure. If
any sign of cracking, scuffing, or worn spots are found,
replace the brake hoses immediately.
BRAKE FLUID
WARNING: The use of incorrect fluid in the brake system may cause
damage to components. DO NOT use any fluid other than DOT-3
brake fluid. DO NOT use reclaimed fluid or fluid that has
been stored in old or open containers. It is essential that
foreign particles and other liquids are kept out of the
brake fluid reservoir.
CATALYTIC CONVERTER
CAUTION: Continued operation of vehicle with a severe malfunction
could cause converter to overheat, resulting in possible
damage to converter and vehicle.
COOLANT
CAUTION: To avoid possible damage to vehicle use only ethylene-glycol
based coolants with a mixture ratio from 50-70% anti-freeze.
DO NOT use 100% anti-freeze as it will cause the formation
of cooling system deposits.
DIESEL FUEL ANTI-FUNGAL ADDITIVES

Removal
Downstream oxygen sensor is mounted on exhaust pipe, behind
catalytic converter. Raise and support vehicle. Disconnect electrical
connector for downstream oxygen sensor. Using Socket (YA8875), remove
downstream oxygen sensor from exhaust pipe.
Installation
If installing original or used downstream oxygen sensor,
apply anti-seize compound on threads of downstream oxygen sensor. A
NEW downstream oxygen sensor should already be coated with anti-seize
compound. Install and tighten downstream oxygen sensor to
specification. See TORQUE SPECIFICATIONS. Install electrical
connector.
ENGINE COOLANT TEMPERATURE SENSOR
Removal & Installation (Dakota 2.5L)
1) Partially drain cooling system. Disconnect electrical
connector at engine coolant temperature sensor. Engine coolant
temperature sensor is located on side of thermostat housing and
contains a Tan/Black wire and a Black/Light Blue wire in the
electrical connector.
2) Remove engine coolant temperature sensor. To install,
reverse removal procedure. Tighten engine coolant temperature sensor
to specification. See TORQUE SPECIFICATIONS. Fill cooling system.
Removal (Dakota 3.9L, 5.2L & 5.9L, Durango & Ram Pickup 3.9L,
5.2L & 5.9L)
1) Partially drain cooling system. Engine coolant temperature
sensor is located on front of intake manifold, near inside of
generator and contains a Tan/Black wire and a Black/Light Blue wire in
the electrical connector.
2) Remove air cleaner if necessary for access to engine
coolant temperature sensor. On models equipped with A/C, go to next
step. On models not equipped with A/C, disconnect electrical connector
at engine coolant temperature sensor. Remove engine coolant
temperature sensor.
3) On A/C equipped models, electrical connector on engine
coolant temperature sensor may be difficult to reach. It may be
necessary to use a coat hanger and fabricate an "L" shaped tool about
8" (203 mm) long to disconnect electrical connector by placing hook
part of tool under electrical connector and pulling electrical
connector upward from engine coolant temperature sensor. Remove engine
coolant temperature sensor.
Installation
To install, reverse removal procedure. Tighten engine coolant
temperature sensor to specification. See TORQUE SPECIFICATIONS. Fill
cooling system.
Removal & Installation (Ram Pickup 8.0L)
1) Partially drain cooling system. Engine coolant temperature
sensor is located on front of intake manifold, near rear of generator
and contains a Tan/Black wire and a Black/Light Blue wire in the
electrical connector.
2) Disconnect electrical connector at engine coolant
temperature sensor. Remove engine coolant temperature sensor.
3) To install, reverse removal procedure. Tighten engine
coolant temperature sensor to specification. See TORQUE
SPECIFICATIONS. Fill cooling system.
Removal (Ram Van & Ram Wagon)

TRANSMISSION TEMPERATURE SENSOR
Removal & Installation (A/T Models)
Transmission temperature sensor is located on transmission
valve body, incorporated into governor pressure sensor. See
appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS
section.
UPSTREAM OXYGEN SENSOR
NOTE: Upstream oxygen sensor may also be referred to as pre
-catalyst oxygen sensor.
Removal
Upstream oxygen sensor is mounted on exhaust pipe, in front
of catalytic converter. Raise and support vehicle. Disconnect
electrical connector for upstream oxygen sensor. Using Socket
(YA8875), remove upstream oxygen sensor from exhaust pipe.
Installation
1) If installing original or used upstream oxygen sensor,
apply anti-seize compound on threads of upstream oxygen sensor. A NEW
upstream oxygen sensor should already be coated with anti-seize
compound.
2) Install and tighten upstream oxygen sensor to
specification. See TORQUE SPECIFICATIONS. Install electrical
connector.
MOTORS, RELAYS & SOLENOIDS
IDLE AIR CONTROL (IAC) MOTOR
Removal & Installation (Dakota, Durango, Ram Pickup 3.9L,
5.2L & 5.9L, Ram Van & Ram Wagon)
1) IAC motor is located on throttle body and contains a 4-pin
electrical connector. On Ram Van and Ram Wagon, remove engine cover.
2) On all models, remove air inlet duct or air cleaner
assembly for access to IAC motor. Disconnect electrical connector at
IAC motor. Remove retaining bolts and IAC motor from throttle body.
3) To install, reverse removal procedure. Tighten IAC motor
retaining bolts to specification. See TORQUE SPECIFICATIONS.
Removal & Installation (Ram Pickup 8.0L)
1) IAC motor is located at rear of throttle body and contains
a 4-pin electrical connector. Remove air inlet duct at air cleaner
assembly. Remove cover from air cleaner assembly.
2) Remove air cleaner housing-to-throttle body nuts and air
cleaner housing from throttle body. Disconnect electrical connector at
IAC motor. Remove retaining bolts and IAC motor.
3) To install, reverse removal procedure. Tighten IAC motor
retaining bolts and air cleaner housing-to-throttle body nuts to
specification. See TORQUE SPECIFICATIONS.
A/C RELAY, AUTO SHUTDOWN (ASD) RELAY & FUEL PUMP RELAY
NOTE: A/C relay may also be referred to as A/C clutch relay or A/C
compressor clutch relay.
Removal & Installation
Relays are located in Power Distribution Center (PDC). Relays\
may be identified by label on inside of PDC cover. See POWER
DISTRIBUTION CENTER (PDC) LOCATION table.

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

PCM.
MISCELLANEOUS CONTROLS
NOTE: Although not strictly considered part of engine performance
system, some controlled devices can adversely affect
driveability if they malfunction.
A/C CLUTCH RELAY
A/C clutch relay is controlled by PCM. When A/C or Defrost
mode is selected and PCM receives A/C request signal from evaporator
switch, PCM will cycle clutch on and off through A/C clutch relay.
When this relay is energized during engine operation, PCM will
determine correct engine idle speed through IAC motor.
When PCM senses low idle speed or wide open throttle through
TP sensor, PCM will de-energize A/C clutch relay, preventing A/C
operation.
AUTO SHUTDOWN (ASD) RELAY & FUEL PUMP RELAY
ASD relay and electric fuel pump relay are energized when
ignition is on. These relays are controlled through PCM by switching a
common ground circuit on and off. Following components are controlled
by ASD and fuel pump relays:
* Electric Fuel Pump
* Fuel Injectors
* Generator Field Winding
* Ignition Coil(s)
* HO2S Heating Element
When ignition switch is turned to RUN position, PCM energizes
ASD relay and electric fuel pump relay which powers these components.
If PCM does not receive a CMP and CKP sensor signal within one second
of engine cranking (start-up), PCM will turn ground circuit off and
de-energize ASD relay.
GENERATOR
Powertrain Control Module (PCM) regulates charging system
voltage.
LIMP-IN MODE
Limp-in mode is the attempt by PCM to compensate for failure
of certain components by substituting information from other sources
so that vehicle can still be operated. If PCM senses incorrect data or
no data at all from MAP sensor, TP sensor, ECT sensor or battery
voltage, system is placed into limp-in mode and Malfunction Indicator
Light (MIL) on instrument panel comes on.
If faulty sensor comes back on line, PCM will resume closed
loop operation. On some vehicles, MIL will remain on until ignition is
shut off and vehicle is restarted. To prevent damage to catalytic
converter, vehicle should NOT be driven for extended periods in limp-
in mode.
RADIATOR FAN RELAY
Electric cooling fan is used only on Dakota. Using
information supplied by A/C signal (if equipped), ECT sensor, and VSS,\