check engine light DODGE NEON 2000 Service Owner's Guide

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)

CLEANING AND INSPECTION
VALVE BODY
Allow all parts to soak a few minutes in a suitable
clean solvent. Wash thoroughly and blow dry with
compressed air. Be sure all passages are clean and
free from obstructions.
Inspect manual and throttle valve operating levers
and shafts for being bent, worn or loose. If a lever is
loose on its shaft, it should be replaced. Do not
attempt to straighten bent levers.
Inspect all mating surfaces for burrs, nicks and
scratches. Minor blemishes may be removed with cro-
cus cloth, using only a very light pressure. Using a
straightedge, inspect all mating surfaces for warpage
or distortion. Slight distortion may be corrected,
using a surface plate. Be sure all metering holes in
steel plate are open. Using a penlight, inspect bores
in valve body for scores, scratches, pits, and irregu-
larities.
Inspect all valve springs for distortion and col-
lapsed coils. Inspect all valves and plugs for burrs,
nicks, and scores. Small nicks and scores may be
removed with crocus cloth, providing extreme care is
taken not to round off sharp edges. The sharpness of
these edges is vitally important. It prevents foreign
matter from lodging between valve and valve body.
This reduces the possibility of sticking. Inspect all
valves and plugs for freedom of operation in valve
body bores.
When bores, valves, and plugs are clean and dry,
the valves and plugs should fall freely in the bores.
The valve body bores do not change their dimensions
with use. Therefore, a valve body that was function-
ing properly when vehicle was new, will operate cor-
rectly if it is properly and thoroughly cleaned. There
is no need to replace a valve body unless it is dam-
aged in handling.
ADJUSTMENTS
GEARSHIFT CABLE
Normal operation of the Park/Neutral Position
Switch provides a quick check to confirm proper link-
age adjustment. The engine starter should only oper-
ate when the transaxle shift lever is in the PARK (P)
or NEUTRAL (N) positions.
If the engine starts in any other gear position, or
the vehicle rolls when the shifter is in gated PARK
(P), a gearshift cable adjustment is necessary.
ADJUSTMENT
(1) Loosen set screw and remove knob from shifter
handle (Fig. 214).(2) Remove the center console assembly as shown
in (Fig. 215).
(3)Adjust gearshift cable as follows:
(a) Place gearshift lever in the PARK (P) posi-
tion.
(b) Loosen shift cable adjustment screw (Fig.
216).
(c) Move transaxle manual lever to the PARK.
Verify transaxle is in PARK by attempting to roll
vehicle in either direction.
Fig. 214 Gearshift Knob Removal/Installation
1 ± SHIFTER KNOB
2 ± SET SCREW
Fig. 215 Center Console Removal/Installation
1 ± CONSOLE
2 ± SCREW (4)
3 ± SCREW (2)
PLTRANSAXLE 21 - 135

²200 revolution increments for immediate cata-
lyst damage
²1000 revolution increments for emissions viola-
tion and Inspection/Maintenance (I/M) test failure
NOTE: The percent of misfire for malfunction crite-
ria varies due to RPM and load. As the engine
speed increases or load decreases, the effects of a
misfire diminishes due to crankshaft momentum.
Failure percentages also vary from engine to
engine.
Monitor OperationÐThe PCM utilizes the
Crankshaft Speed Fluctuation method to monitor for
misfire. The misfire monitor utilizes a crankshaft
position sensor to determine engine RPM. The sensor
can detect slight variations in engine speed due to
misfire. Misfire is continuously monitored once the
enabling conditions are met.
Once enabling conditions are met, the PCM counts
the number of misfires in every 200 revolutions of
the crankshaft. If, duringfive200 counters, the mis-
fire percentage exceeds a predetermined value, a
maturing code is set and a Freeze Frame is entered.
Freeze Frame data is recorded during the last 200
revolutions of the 1000 revolution period. A failure on
the second consecutive trip matures the code and a
DTC is set.
If misfire continues during the initial trip, the MIL
is not illuminated. However, the MIL flashes when
the misfire percentage exceeds the malfunction per-
centage, in any 200 revolution period, that would
cause permanent catalyst damage. This is a one trip
monitor. If misfire reaches a point in which catalyst
damage is likely to occur, the MIL flashes and a DTC
is stored in a Freeze Frame. The engine defaults to
open loop operation to prevent increased fuel flow to
the cylinders. Once misfire is below the predeter-
mined percentage, the MIL stops flashing but
remains illuminated.
The 1000 revolution counters are two trip moni-
tors. As with the fuel system monitor, Freeze Frame
data is from the original fault, and MIL extinguish-
ing requires the monitor to pass under similar condi-
tions.
The Adaptive NumeratorÐThe Misfire Monitor
takes into account component wear, sensor fatigue
and machining tolerances. The PCM compares the
crankshaft in the vehicle to data on an ideal crank
and uses this as a basis to determine variance. To do
this, the crankshaft sensor monitors the reference
notches in the crank. The PCM uses the first signal
set as a point of reference. It then measures where
the second set of signals is, compared to where engi-
neering data has determined it should be. This vari-
ance is the Adaptive Numerator. The monitor will not
run if the numerator is not set.If the Adaptive Numerator is equal to the default
value, the adaptive Numerator has not been learned
and the Misfire Monitor does not run. If the Adaptive
Numerator exceeds its limits, the PCM sets a DTC
for Adaptive Numerator and illuminates the MIL.
RPM ErrorÐThe PCM also checks the machining
tolerances for each group of slots. By monitoring the
speed of the crank from the first slot to the last slot
in a group, the PCM can calculate engine RPM. The
variance between groups of slots is know as the RPM
error. In order for the PCM to run the Misfire Mon-
itor, RPM error must be less than approximately 5%.
Enabling ConditionsÐThe following conditions
must be met before the PCM runs the Misfire Moni-
tor:
²RPM
²Engine Coolant Temperature (ECT)
²Barometric Pressure (MAP)
²Fuel level
²Ambient air Temperature
Pending ConditionsÐThe Misfire Monitor does
not run when the MIL is illuminated for any of the
following:
²Limp in mode for
Ð MAP
Ð TPS
Ð Crankshaft Sensor
Ð Engine Coolant Temperature Sensor
²Speed Sensor DTC
²EGR Electrical
²EVAP Electrical
²Idle Speed Faults
²Intake Air Temperature
²Oxygen Sensor Monitor
²Oxygen Sensor Electrical
Conflict ConditionsÐIf any of the following con-
ditions conflict with the Misfire Monitor, the monitor
will not run:
²Low fuel level
²MAP voltage rapidly changing
²Severe engine decel
²TPS toggling OPEN/CLOSED
²Engine RPM too low (RPM levels by vehicle)
²Engine RPM too high (RPM levels vary by vehi-
cle)
²Full Lean or Decel Fuel Shut-off
²Cold start
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the air fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
25 - 16 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO2 PERSONAL INJURY CAN RESULT.
(7) If suction side low pressure is within specified
range, freeze the expansion valve control head (Fig.
13) for 30 seconds. Use a super cold substance (liquid
CO2).Do not spray refrigerant on the expansion
valve for this test.Suction side low pressure should
drop to 34.5 kPa (5 psi) If not, replace expansion
valve.(8) Allow expansion valve to thaw. The low pres-
sure gauge reading should stabilize at 103 to 241
kPa (15 to 35 psi). If not, replace expansion valve.
(9) When expansion valve test is complete, test
A/C overall performance. Refer to the Heater and A/C
Performance Test in this section. Remove all test
equipment before returning vehicle to use.
HEATER PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
Review Safety Precautions and Warnings in this
group before performing the following procedures.
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference chart.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
Fig. 12 Evaporator Probe Harness Connector
1 ± PIN #3
2 ± PIN #2
3 ± PIN #1
Fig. 13 Expansion Valve & Low Pressure Cut-Off
Switch - Typical
1 ± EXPANSION VALVE
2 ± LOW PRESSURE CUT OFF SWITCH
3 ± SUCTION LINE
4 ± CONTROL HEAD
TEMPERATURE REFERENCE CHART
Ambient Temp. Minimum
FloorOutlet
Temp.
Celsius Fahrenheit Celsius Fahrenheit
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
PLHEATING AND AIR CONDITIONING 24 - 13
DIAGNOSIS AND TESTING (Continued)