exhaust DODGE NEON 2000 Service Service Manual

grammed (fixed) values and inputs from other sen-
sors.
DOWNSTREAM OXYGEN SENSOR 1/2
The Downstream O2 Sensor has two functions.
One function is measuring catalyst efficiency. This is
an OBD II requirement. The oxygen content of theexhaust gasses has significantly less fluctuation than
at the inlet if the converter is working properly. The
PCM compares upstream and Downstream O2 Sen-
sor switch rates under specific operating conditions
to determine if the catalyst is functioning properly.
The other function is a downstream fuel control
which was introduced in 1996. The upstream O2 goal
varies within the window of operation of the O2 Sen-
sor. In the past the goal was a preprogrammed fixed
value based upon where it believed the catalyst oper-
ated most efficiently.
While the Upstream O2 Sensor input is used to
maintain the 14.7:1 air/fuel ratio, variations in
engines, exhaust systems and catalytic converters
may cause this ratio to not be the most ideal for a
particular catalyst and engine. To help maintain the
catalyst operating at maximum efficiency, the PCM
will fine tune the air/fuel ratio entering the catalyst
based upon the oxygen content leaving the catalyst.
This is accomplished by modifying the Upstream O2
Sensor voltage goal.
If the exhaust leaving the catalyst has too much
oxygen (lean ) the PCM increases the upstream O2
goal which increases fuel in the mixture causing less
oxygen to be left over. Conversely, if the oxygen con-
tent leaving the catalyst has is too little oxygen (rich)
the PCM decreases the upstream O2 goal down
which removes fuel from the mixture causing more
oxygen to be left over. This function only occurs dur-
ing downstream closed loop mode operation.
Fig. 13 Heated Oxygen Sensor Systems
1 ± CATALYTIC CONVERTER (LEV EMISSION)
2 ± CLOSE-COUPLED CATALYTIC CONVERTER
(ULEV EMISSION)
3 ± UNDER-FLOOR CATALYTIC CONVERTER
(ULEV EMISSION)
4 ± OXYGEN SENSORS5 ± OXYGEN SENSOR
6 ± CATALYTIC CONVERTER
(FEDERAL EMISSION)
7 ± OXYGEN SENSOR
Fig. 14 Types Of O2 Sensors
1 ± BOSCH
2 ± NEW NTK
3 ± NTK
PLFUEL SYSTEM 14 - 33
DESCRIPTION AND OPERATION (Continued)

stroke. One plug is the cylinder under compression,
the other cylinder fires on the exhaust stroke. Coil
number one fires cylinders 1 and 4. Coil number two
fires cylinders 2 and 3. The PCM determines which
of the coils to charge and fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing the
spark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor and
camshaft position sensor inputs. Refer to Auto Shut-
down (ASD) RelayÐPCM Output in this section for
relay operation.
Base timing is non-adjustable, but is set from the
factory at approximately 10ÉBTDC when the engine
is warm and idling.
There is an adaptive dwell strategy that runs dwell
from 4 to 6 msec when rpm is below 3,000 and bat-
tery voltage is 12-14 volts. During cranking, dwell
can be as much as 200 msec. The adaptive dwell is
driven by the sensed current flow through the injec-
tor drivers. Current flow is limited to 8 amps.
The low resistance of the primary coils can allow
current flow in excess of 15 amps. The PCM has a
current sensing device in the coil output circuit. As
dwell time starts, the PCM allows current to flow.
When the sensing device registers 8 amps, the PCM
begins to regulate current flow to maintain and not
exceed 8 amps through the remainder of the dwell
time. This prevents the PCM from being damaged by
excess current flow.
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
OPERATION
The PCM supplies the malfunction indicator (check
engine) lamp on/off signal to the instrument panel
through the PCI Bus. The PCI Bus is a communica-
tions port. Various modules use the PCI Bus to
exchange information.
The Check Engine lamp comes on each time the
ignition key is turned ON and stays on for 3 seconds
as a bulb test.
The Malfunction Indicator Lamp (MIL) stays on
continuously, when the PCM has entered a Limp-In
mode or identified a failed emission component. Dur-
ing Limp-in Mode, the PCM attempts to keep the
system operational. The MIL signals the need for
immediate service. In limp-in mode, the PCM com-
pensates for the failure of certain components that
send incorrect signals. The PCM substitutes for the
incorrect signals with inputs from other sensors.
If the PCM detects active engine misfire severe
enough to cause catalyst damage, it flashes the MIL.
At the same time the PCM also sets a Diagnostic
Trouble Code (DTC).
For signals that can trigger the MIL (Check
Engine Lamp) refer to the On-Board Diagnos-
tics section.
SPEED CONTROLÐPCM INPUT
OPERATION
The speed control system provides five separate
voltages (inputs) to the Powertrain Control Module
(PCM). The voltages correspond to the ON, OFF,
SET, RESUME, CANCEL, and COAST.
The speed control ON voltage informs the PCM
that the speed control system has been activated.
The speed control SET voltage informs the PCM that
a fixed vehicle speed has been selected. The speed
control RESUME voltage indicates the previous fixed
speed is requested. The speed control CANCEL volt-
age tells the PCM to deactivate but retain set speed
in memory (same as depressing the brake pedal). The
speed control COAST voltage informs the PCM to
coast down to a new desired speed. The speed control
OFF voltage tells the PCM that the speed control
system has deactivated. Refer to the Speed Control
section for more speed control information.
SCI RECEIVEÐPCM OUTPUT
OPERATION
SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Fig. 27 Ignition Coil Pack
PLFUEL SYSTEM 14 - 41
DESCRIPTION AND OPERATION (Continued)

(5) Remove the nut from the upper bracket mount.
(6) Raise vehicle and support on hoist.
(7) Remove 2 lower bracket bolts (Fig. 39).
(8) Remove 4 screws from bracket and remove
bracket from PCM (Fig. 40).
INSTALLATION
(1) Install bracket to PCM and tighten screws.
(2) Install PCM and bracket to body and tighten
the 2 lower bolts.
(3) Lower vehicle.
(4) Install upper bracket nut and tighten.
(5) Clip in wiring harness bracket.
(6) Install gray and black connectors to the PCM.
(7) Install the air cleaner box, refer to the air
cleaner box section.(8) Connect the negative battery cable.
UPSTREAM HEATED OXYGEN SENSOR
REMOVAL
(1) Raise and support vehicle.
(2) Unplug sensor connector.
(3) Remove sensor using an oxygen sensor crow
foot wrench such as Snap-On tool YA8875 or equiva-
lent (Fig. 41).
(4) After removing the sensor, the exhaust mani-
fold threads must be cleaned with an 18 mm X 1.5 +
6E tap. If reusing the original sensor, coat the sensor
threads with an anti-seize compound such as Loctitet
771-64 or equivalent.
Fig. 38 PCM Wiring Bracket
Fig. 39 Lower Mounting Bolts
Fig. 40 PCM Bracket Screws
Fig. 41 Upstream Heated Oxygen Sensor Removal/
Installation
1 ± EXHAUST PIPE FLANGE
2 ± CROW FOOT WRENCH
3 ± UPSTREAM OXYGEN SENSOR
PLFUEL SYSTEM 14 - 45
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
New sensors have compound on the threads and do
not require an additional coating.
(1) Install sensor using an oxygen sensor crow foot
wrench such as Snap-On tool YA8875 or equivalent
(Fig. 41). Tighten the sensor to 28 N´m (20 ft. lbs.)
torque.
(2) Plug sensor connector.
(3) Lower vehicle.
DOWNSTREAM HEATED OXYGEN SENSOR 1/2
The downstream heated oxygen sensor threads into
the exhaust outlet pipe behind the catalytic convertor
(Fig. 42).
REMOVAL
(1) Raise vehicle.
(2) Disconnect electrical connector from harness.
(3) Disconnect sensor electrical harness from clips
along body.
(4) Remove sensor using an oxygen sensor crow
foot wrench such as Snap-On tool YA8875 or equiva-
lent (Fig. 43).
(5) After removing the sensor, the exhaust mani-
fold threads must be cleaned with an 18 mm X 1.5 +
6E tap. If reusing the original sensor, coat the sensor
threads with an anti-seize compound such as Loctitet
771-64 or equivalent.
INSTALLATION
New sensors have compound on the threads and do
not require an additional coating.
(1) Install sensor using an oxygen sensor crow foot
wrench such as Snap-On tool YA8875 or equivalent
(Fig. 43). Tighten the sensor to 28 N´m (20 ft. lbs.)
torque.
(2) Connect sensor electrical harness from clips
along body.
(3) Connect electrical connector to harness.
(4) Lower vehicle.
AIR CLEANER BOX
REMOVAL
(1) Remove 5 screws from air cleaner element box
lid.
(2) Remove lid from air cleaner box.
(3) Pull air cleaner up and out of air cleaner box
(Fig. 44).
(4) Move air duct out of the way.
(5) Remove the bolt and nut from the air cleaner
box.
(6) Remove wiring harness from the clips on the
air cleaner box.
(7) Remove the wiring clip from the front of the air
cleaner box.(8) Remove the 4 bolts from the air cleaner box to
throttle body.
(9) Pull air cleaner box up and off of stud and bat-
tery tray and remove from vehicle.
INSTALLATION
(1) Install air cleaner box. Make sure that it is on
the battery tray tab in the back and on the stud on
the side.
(2) Install the bolts to the throttle body and
tighten.
(3) Install the nut and bolt for air cleaner box and
tighten.
(4) Install the wiring clip in the front of the air
cleaner box.
Fig. 42 Downstream Heated Oxygen Sensor
1 ± CATALYTIC CONVERTOR
2 ± DOWNSTREAM OXYGEN SENSOR
Fig. 43 Downstream Heated Oxygen Sensor
Removal/Installation
1 ± DOWNSTREAM HEATED OXYGEN SENSOR
2 ± CATALYTIC CONVERTOR
14 - 46 FUEL SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

CAUTION: Do not force the pump to operate
against the stops for more than 5 seconds at a time
as pump damage may result.
(6) Completely open the valve on the Power Steer-
ing Analyzer flow meter. Turn the steering wheel to
the extreme left until the stop in the steering gear is
met, then turn the steering wheel to the right until
the right stop is met. Record the highest indicated
pressure at each position. Compare the recorded
readings to the specifications. If the highest output
pressure reading against one stop is within 50 psi of
the highest reading at the other stop, the steering
gear is leaking internally and must be replaced.
If the power steering gear requires replacement,
refer to the section POWER STEERING GEAR
within this group for the removal and installation
procedure.
SERVICE PROCEDURES
POWER STEERING SYSTEM FLUID LEVEL
CHECK
WARNING: FLUID LEVEL SHOULD BE CHECKED
WITH THE ENGINE OFF TO PREVENT PERSONAL
INJURY FROM MOVING PARTS.
Before opening power steering system, wipe the
reservoir filler cap free of dirt and debris. Remove
the cap and check the fluid level on its dipstick.
When the fluid is at normal ambient temperature,
approximately 21ÉC to 27ÉC (70ÉF to 80ÉF), the dip-
stick level should indicateCOLD. Do not overfill the
power steering system. In all power steering systems,
use only Mopar Power Steering Fluid, or its equiva-
lent.
NOTE: Do not use any type of automatic transmis-
sion fluid in the power steering system.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
WARNING: POWER STEERING FLUID, ENGINE
PARTS AND EXHAUST SYSTEM MAY BE
EXTREMELY HOT IF ENGINE HAS BEEN RUNNING.
DO NOT START ENGINE WITH ANY LOOSE OR DIS-
CONNECTED HOSES. DO NOT ALLOW HOSES TO
TOUCH HOT EXHAUST MANIFOLD OR CATALYST.WARNING: FLUID LEVEL SHOULD BE CHECKED
WITH THE ENGINE OFF TO PREVENT PERSONAL
INJURY FROM MOVING PARTS.
CAUTION: When the system is open, cap all open
ends of the hoses, power steering pump fittings or
power steering gear ports to prevent entry of for-
eign material into the components.
NOTE: Do not use any type of automatic transmis-
sion fluid in the power steering system.
POWER STEERING FLUID PRESSURE HOSE
NOTE: Before proceeding with this removal and
installation procedure, review SERVICE WARNINGS
AND CAUTIONS at the beginning of REMOVAL AND
INSTALLATION in this section.
REMOVAL
(1) Siphon as much fluid as possible from the
power steering fluid reservoir.
(2) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group in this
service manual for the correct lifting procedure.
(3) Back out the tube nut securing the power
steering fluid pressure hose to the gear (Fig. 6).
Fig. 6 Power Steering Hoses At Gear
1 ± PRESSURE HOSE TUBE NUT
2 ± RETURN HOSE
3 ± POWER STEERING GEAR
4 ± FRONT SUSPENSION CROSSMEMBER
PLSTEERING 19 - 11
DIAGNOSIS AND TESTING (Continued)

(4) Open the routing clips on the right side of the
power steering gear and remove the power steering
fluid pressure hose tube from the routing clips. At
the same time, remove the pressure hose tube from
the gear.
(5) Lower the vehicle.
(6) Remove the bolt securing the hose routing clip
in place on the right engine motor mount (Fig. 7).
Remove the power steering fluid pressure hose from
the routing clip.
(7) Back out the tube nut securing the power
steering fluid pressure hose to the power steering
pump and remove the hose from the pump (Fig. 7).
(8) Remove the power steering pressure hose from
the engine compartment.
INSTALLATION
(1) Install the power steering pressure hose into
the engine compartment from the top. First, guide
the pump end of the hose under the pump, then
route the rest of the hose along the right side of the
engine. Guide the gear end of the hose down behind
the back of the engine towards the power steering
gear.
(2) Using a lint free towel, wipe clean the open
power steering hose end and the power steeringpump port. Replace the used O-ring with new. Lubri-
cate the O-ring with power steering fluid.
(3) Attach the power steering fluid pressure hose
to the outlet fitting on the bottom of the power steer-
ing pump (Fig. 7). Tighten the pressure hose tube
nut to a torque of 34 N´m (25 ft. lbs.).
(4) Install the power steering fluid pressure hose
in the routing clip and attach the clip to the right
engine mount (Fig. 7). Tighten the hose routing clip
bolt to a torque of 12 N´m (105 in. lbs.).
(5) Raise the vehicle.
CAUTION: The power steering fluid hoses must
remain away from the exhaust system, vehicle com-
ponents, and unfriendly surfaces that can cause
possible damage to the power steering hoses.
(6) Using a lint free towel, wipe clean the open
power steering hose end and the power steering gear
port. Replace the used O-ring with new. Lubricate
the O-ring with power steering fluid.
(7) Attach the power steering fluid pressure hose
to the port on the power steering gear (Fig. 6). Start
the tube nut threads into the gear, but do not tighten
it at this time.
(8) Open the routing clips on the right side of the
power steering gear and install the power steering
fluid pressure hose into the routing clips. Close the
clips.
(9) Tighten the pressure hose tube nut at the gear
to a torque of 34 N´m (25 ft. lbs.).
(10) Lower the vehicle.
(11) Perform the POWER STEERING PUMP INI-
TIAL OPERATION service procedure which can be
found in the POWER STEERING PUMP section of
this group to properly fill and bleed the power steer-
ing system.
(12) Check for leaks at all hose connections.
POWER STEERING FLUID RETURN HOSE
NOTE: Before proceeding with this removal and
installation procedure, review SERVICE WARNINGS
AND CAUTIONS at the beginning of REMOVAL AND
INSTALLATION in this section.
REMOVAL
(1) Siphon as much fluid as possible from the
power steering fluid reservoir.
(2) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group in this
service manual for the correct lifting procedure.
(3) If the vehicle is equipped with a power steering
fluid cooler, remove the hose clamp securing the
return hose to the cooler. Slide the hose off the end of
the cooler tube.
Fig. 7 Power Steering Hoses At Pump
1 ± HOSE ROUTING CLIP
2 ± RETURN HOSE CLAMP
3 ± POWER STEERING PUMP AND RESERVOIR
4 ± PRESSURE HOSE TUBE NUT
19 - 12 STEERINGPL
REMOVAL AND INSTALLATION (Continued)

(4) If the vehicle is not equipped with a power
steering fluid cooler:
²Remove the hose clamp securing the return hose
to the steel fitting in the outlet port on the power
steering gear (Fig. 6).
²Slide the hose off the end of the steel fitting.
²Pull the hose loose from the C-clamps on the two
routing clips located on the front of the steering gear
(Fig. 6).
(5) Lower the vehicle.
(6) Remove the bolt securing the hose routing clip
in place on the right engine mount (Fig. 7). Remove
the power steering fluid return hose from the routing
clip.
(7) Remove the hose clamp securing the return
hose to the power steering fluid reservoir (Fig. 7).
Slide the hose off the end of the reservoir fitting.
(8) Remove the power steering return hose from
the engine compartment.
INSTALLATION
(1) Slide a hose clamp onto the power steering
pump end of the hose far enough to clear the fitting
on the power steering fluid reservoir once the hose is
installed.
(2) Install the power steering return hose into the
engine compartment from the top. First, guide the
pump end of the hose onto the fitting on the power
steering fluid reservoir, then route the rest of the
hose along the right side of the engine (Fig. 7). Guide
the gear end of the hose down behind the back of the
engine towards the power steering gear.
(3) Expand the hose clamp and slide it onto the
fluid reservoir fitting. Secure the clamp once it is
past the bead formed into the fluid reservoir fitting.
(4) Install the power steering fluid return hose in
the hose routing clip and attach the clip to the right
engine mount (Fig. 7). Tighten the hose routing clip
bolt to a torque of 12 N´m (105 in. lbs.).
(5) Raise the vehicle.
CAUTION: The power steering fluid hoses must
remain away from the exhaust system, vehicle com-
ponents, and unfriendly surfaces that can cause
possible damage to the power steering hoses.
(6) Using a lint free towel, wipe clean the open
power steering hose end and the power steering gear
port fitting or power steering fluid cooler port.
(7) Install a hose clamp onto the end of the hose
far enough to clear the fitting on the steering gear or
cooler once the hose is installed.
(8) If the vehicle is equipped with a power steering
fluid cooler, slide the hose onto the end of the cooler
tube. Install the hose clamp past the bead formed
into the cooler tube and secure in place.(9) If the vehicle is not equipped with a power
steering fluid cooler:
²Slide the hose onto the end of the steel fitting in
the steering gear outlet port (Fig. 6).
²Install the hose clamp past the bead formed into
the steel fitting and secure in place.
²Align and attach the hose to the C-clamps on
the two routing clips located on the front of the steer-
ing gear (Fig. 6).
(10) Lower the vehicle.
(11) Perform the POWER STEERING PUMP INI-
TIAL OPERATION service procedure which can be
found in the POWER STEERING PUMP section of
this group to properly fill and bleed the power steer-
ing system.
(12) Check for leaks at all hose connections.
POWER STEERING FLUID COOLER
NOTE: Before proceeding with this removal and
installation procedure, review SERVICE WARNINGS
AND CAUTIONS at the beginning of REMOVAL AND
INSTALLATION in this section.
REMOVAL
(1) Siphon as much fluid as possible from the
power steering fluid reservoir.
(2) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group in this
service manual for the correct lifting procedure.
(3) Remove the hose clamp, attaching the power
steering fluid return hose to the power steering fluid
cooler. Remove the return hose from the cooler.
(4) Remove the hose clamp attaching the power
steering cooler fluid hose to the steel fitting in the
power steering gear outlet port (Fig. 8).
(5) Remove the two screws securing the cooler to
the front suspension crossmember. They are located
behind the cooler. They can be accessed from above.
(6) Open the routing clip on the right front of the
power steering gear housing and remove the cooler
tube from it.
(7) Remove the cooler from the vehicle.
INSTALLATION
(1) Slide a hose clamp onto the end of the power
steering cooler fluid hose far enough to clear the steel
fitting on the power steering gear once the hose is
installed.
(2) Slide the hose (with cooler attached) onto the
fitting on the steering gear, then align the tube on
back of the cooler with the open routing clip on the
right front of the power steering gear housing, and
snap it into place. Close the clip.
PLSTEERING 19 - 13
REMOVAL AND INSTALLATION (Continued)

reduces the power required to drive the pump and
holds down temperature build-up.
When steering conditions exceed maximum pres-
sure requirements, such as when the wheels are
turned against the stops, the pressure built up in the
steering gear exerts pressure on the spring end of the
flow control valve. The high pressure lifts the relief
valve ball from its seat and allows oil to flow through
a trigger orifice located in the outlet fitting. This
reduces pressure on the spring end of the flow con-
trol valve which then opens and allows the oil to
return to the intake side of the pump. This action
limits maximum pressure output of the pump to a
safe level.
Under normal power steering pump operating con-
ditions, pressure requirements of the pump are below
maximum, causing the pressure relief valve to
remain closed.
POWER STEERING FLUID RESERVOIR
The power steering fluid reservoir is mounted on
the power steering pump using 3 bolts (Fig. 1). It
stores fluid for the power steering system.
The power steering fluid reservoir is considered an
integral part of the power steering pump and is not
serviced separately.
SERVICE PROCEDURES
POWER STEERING PUMP INITIAL OPERATION
CAUTION: The fluid level should be checked with
engine off to prevent injury from moving compo-
nents. Use only MoparTPower Steering Fluid. Do
not use automatic transmission fluid. Do not over-
fill.
Wipe the filler cap clean, then check the fluid level.
The dipstick should indicateCOLDwhen the fluid is
at normal temperature, approximately 21ÉC to 27ÉC
(70ÉF to 80ÉF).
(1) Fill the power steering fluid reservoir to the
proper level and let the fluid settle for at least two
minutes.
(2) Start the engine and let run for a few seconds,
then turn the engine off.
(3) Add fluid if necessary. Repeat the above proce-
dure until the fluid level remains constant after run-
ning the engine.
(4) Raise the front wheels off the ground.
(5) Start the engine. Slowly turn the steering
wheel right and left, lightly contacting the wheel
stops.
(6) Add power steering fluid if necessary.
(7) Lower the vehicle and turn the steering wheel
slowly from lock to lock.(8) Stop the engine. Check the fluid level and refill
as required.
(9) If the fluid is extremely foamy, allow the vehi-
cle to stand a few minutes and repeat the above pro-
cedure.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
WARNING: POWER STEERING FLUID, ENGINE
PARTS AND EXHAUST SYSTEM MAY BE
EXTREMELY HOT IF ENGINE HAS BEEN RUNNING.
DO NOT START ENGINE WITH ANY LOOSE OR DIS-
CONNECTED HOSES. DO NOT ALLOW HOSES TO
TOUCH HOT EXHAUST MANIFOLD OR CATALYST.
WARNING: FLUID LEVEL SHOULD BE CHECKED
WITH THE ENGINE OFF TO PREVENT PERSONAL
INJURY FROM MOVING PARTS.
CAUTION: When the system is open, cap all open
ends of the hoses, power steering pump fittings or
power steering gear ports to prevent entry of for-
eign material into the components.
NOTE: Do not use any type of automatic transmis-
sion fluid in the power steering system.
POWER STEERING PUMP
NOTE: Before proceeding with this removal and
installation procedure, review SERVICE WARNINGS
AND CAUTIONS at the beginning of REMOVAL AND
INSTALLATION in this section.
REMOVAL
(1) Remove battery cable from the negative post on
the battery.
(2) Siphon as much fluid as possible from the
power steering fluid reservoir.
(3) Remove the power steering pump drive belt
from the power steering pump pulley. Refer to
ACCESSORY DRIVE BELTS in the COOLING SYS-
TEM service manual group for the required removal
and installation procedure.
(4) Remove the hose clamp securing the return
hose to the power steering fluid reservoir. Slide the
hose off the end of the reservoir fitting. (Fig. 2).
(5) Back out the tube nut securing the power
steering fluid pressure hose to the power steering
pump and remove the hose from the pump (Fig. 2).
PLSTEERING 19 - 17
DESCRIPTION AND OPERATION (Continued)

NOTE: The power steering gear should not be ser-
viced or adjusted. If a malfunction or oil leak occurs
with the steering gear, the complete steering gear
needs to be replaced.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
WARNING: POWER STEERING FLUID, ENGINE
PARTS AND EXHAUST SYSTEM MAY BE
EXTREMELY HOT IF ENGINE HAS BEEN RUNNING.
DO NOT START ENGINE WITH ANY LOOSE OR DIS-
CONNECTED HOSES. DO NOT ALLOW HOSES TO
TOUCH HOT EXHAUST MANIFOLD OR CATALYST.
WARNING: FLUID LEVEL SHOULD BE CHECKED
WITH THE ENGINE OFF TO PREVENT PERSONAL
INJURY FROM MOVING PARTS.
CAUTION: When the system is open, cap all open
ends of the hoses, power steering pump fittings or
power steering gear ports to prevent entry of for-
eign material into the components.
NOTE: Do not use any type of automatic transmis-
sion fluid in the power steering system.
POWER STEERING GEAR
NOTE: Before proceeding with this removal and
installation procedure, review SERVICE WARNINGS
AND CAUTIONS at the beginning of REMOVAL AND
INSTALLATION in this section.
REMOVAL
(1) Place the steering wheel in the STRAIGHT-
AHEAD position. Using a steering wheel holder, lock
the steering wheel in place to keep it from rotating
(Fig. 2). This keeps the clockspring in the proper ori-
entation.
(2) Inside the passenger compartment, remove the
steering column coupling retainer pin, back off the
pinch bolt nut, and remove the steering column cou-
pling pinch bolt (Fig. 3) (the pinch bolt nut is caged
to the coupling and is not removable). Separate the
upper and lower steering column couplings.
(3) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group in this
service manual for the correct lifting procedure.(4) Remove both front tire and wheel assemblies
from the vehicle.
(5) Remove nuts attaching both outer tie rods to
the steering knuckles (Fig. 4). Remove each nut by
holding the tie rod stud stationary while loosening
and removing the nut with a wrench.
(6) Remove the outer tie rod from the steering
knuckles using Remover, Special Tool MB991113
(Fig. 5).
(7) Remove the tie rod heat shield.
Fig. 2 Steering Wheel Holder
1 ± STEERING WHEEL
2 ± STEERING WHEEL HOLDER
3 ± DRIVERS SEAT
Fig. 3 Steering Column Couplings
1 ± STEERING COLUMN UPPER COUPLING
2 ± PINCH BOLT
3 ± STEERING COLUMN LOWER COUPLING
4 ± BRAKE PEDAL
5 ± NUT
6 ± RETAINER PIN
19 - 22 STEERINGPL
DESCRIPTION AND OPERATION (Continued)

TIRE WEAR PATTERNS
Under inflation will cause wear on the shoulders of
tire. Over inflation will cause wear at the center of
tire.
Excessive camber causes the tire to run at an
angle to the road. One side of tread is then worn
more than the other (Fig. 4).
Excessive toe-in or toe-out causes wear on the
tread edges and a feathered effect across the tread
(Fig. 4).
TIRE NOISE OR VIBRATION
Radial-ply tires are sensitive to force impulses
caused by improper mounting, vibration, wheel
defects, or possibly tire imbalance.To find out if tires are causing the noise or vibra-
tion, drive the vehicle over a smooth road at varying
speeds. Note the noise level during acceleration and
deceleration. The engine, differential and exhaust
noises will change as speed varies, while the tire
noise will usually remain constant.
VEHICLE LEAD DIAGNOSIS AND CORRECTION
Use the following chart to diagnose a vehicle that
has a complaint of a drift or lead condition. The use
of this chart will help to determine if the lead condi-
tion is the result of a bad tire or is caused by the
wheel alignment.
Fig. 4 Tire Wear Patterns
22 - 4 TIRES AND WHEELSPL
DIAGNOSIS AND TESTING (Continued)