pressure DODGE NEON 2000 Service Repair Manual

TIRE IDENTIFICATION
Tire type, size, aspect ratio and speed rating are
encoded in the letters and numbers imprinted on the
side wall of the tire. Refer to the chart to decipher
the tire identification code (Fig. 2).
Performance tires will have a speed rating letter
after the aspect ratio number. For example, the letter
ªSº indicates that the tire is speed rated up to 112
mph (180 km/h). The speed rating is not always
printed on the tire sidewall.
²Q -up to 100 mph (160 km/h)
²T -up to 118 mph (190 km/h)
²U -up to 124 mph (200 km/h)
²H -up to 130 mph (210 km/h)
²V -up to 149 mph (240 km/h)
²Z -more than 149 mph (240 km/h) (consult the
tire manufacturer for the specific speed rating)
An All Season type tire will have eitherM+S,M
& S or M-S (indicating mud and snow traction)
imprinted on the side wall.
TIRE CHAINS
Refer to the owners manual supplied with the vehi-
cle to determine whether the use of tire chains is per-
mitted on this vehicle.
RADIAL-PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
Fig. 1 Tire (Typical)
1 ± CAST ALUMINUM WHEEL
2 ± WEIGHTS
3 ± CENTER CAP
4 ± WHEEL COVER5 ± MOUNTING NUTS
6 ± VALVE STEM
7 ± STEEL WHEEL
8 ± TIRE
22 - 2 TIRES AND WHEELSPL
DESCRIPTION AND OPERATION (Continued)

signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
SPARE TIRE±TEMPORARY
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M. P. H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capabilityIt is recommend that tires equivalent to the origi-
nal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehi-
cle.
The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DIAGNOSIS AND TESTING
TREAD WEAR INDICATORS
Tread wear indicators are molded into the bottom
of the tread grooves. When tread depth is 1.6 mm
(1/16 in.), the tread wear indicators will appear as a
13 mm (1/2 in.) band (Fig. 3).
Tire replacement is necessary when indicators
appear in two or more grooves or if localized balding
occurs.
Fig. 2 Tire Identification
Fig. 3 Tread Wear Indicators
1 ± TREAD ACCEPTABLE
2 ± TREAD UNACCEPTABLE
3 ± WEAR INDICATOR
PLTIRES AND WHEELS 22 - 3
DESCRIPTION AND OPERATION (Continued)

SERVICE PROCEDURES
PRESSURE GAUGES
A quality air pressure gauge is recommended to
check tire pressure. After checking the air pressure,
replace valve cap finger tight.
TIRE INFLATION PRESSURES
Under inflation causes rapid shoulder wear, tire
flexing, and can result in tire failure (Fig. 5).
Over inflation causes rapid center wear and loss of
the tire's ability to cushion shocks (Fig. 6).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride²The vehicle to drift.
For proper tire pressure specification refer to the
Tire Inflation Pressure Chart Placard provided with
the vehicle.
Tire pressures have been chosen to provide safe
operation, vehicle stability, and a smooth ride. Tire
pressure should be checked cold once per month.
Check tire pressure more frequently when the
weather temperature varies widely. Tire pressure will
decrease when the outdoor temperature drops.
Inflation pressures specified on the placard are
always the cold inflation pressure of the tire. Cold
inflation pressure is obtained after the vehicle has
not been operated for at least 3 hours, or the vehicle
is driven less than one mile after being inoperative
for 3 hours. Tire inflation pressures may increase
from 2 to 6 pounds per square inch (psi) during oper-
ation. Do not reduce this normal pressure build-up.
WARNING: OVER OR UNDER INFLATED TIRES
CAN AFFECT VEHICLE HANDLING. THE TIRE CAN
FAIL SUDDENLY, RESULTING IN LOSS OF VEHICLE
CONTROL.
TIRE PRESSURE FOR HIGH SPEED
OPERATION
DaimlerChrysler Corporation advocates driving at
safe speeds within posted speed limits. Where speed
limits allow the vehicle to be driven at high speeds,
correct tire inflation pressure is very important. For
speeds up to and including 120 km/h (75 mph), tires
must be inflated to the pressures shown on the tire
placard. For continuous speeds in excess of 120 km/h
(75 mph), tires must be inflated to the maximum
pressure specified on the tire sidewall.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph
(120 km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
TIRE AND WHEEL ROTATION
NON-DIRECTIONAL TREAD PATTERN TIRES
Tires on the front and rear axles operate at differ-
ent loads and perform different functions. For these
reasons, they wear at unequal rates, and tend to
develop irregular wear patterns. These effects can be
reduced by timely rotation of tires. The benefits of
rotation are especially worthwhile. Rotation will
increase tread life, help to maintain mud, snow, and
wet traction levels, and contribute to a smooth, quiet
ride.
Fig. 5 Under Inflation Wear
1 ± THIN TIRE TREAD AREAS
Fig. 6 Over Inflation Wear
1 ± THIN TIRE TREAD AREA
22 - 6 TIRES AND WHEELSPL

OPERATION
BULB CHECK
Each time the ignition key is turned to the ON
position, the malfunction indicator (check engine)
lamp on the instrument panel should illuminate for
approximately 2 seconds then go out. This is done for
a bulb check.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located inthe passenger compartment; at the lower edge of
instrument panel; near the steering column.
(2) Turn the ignition switch on and access the
ªRead Faultº screen.
(3) Record all the DTC's and ªfreeze frameº infor-
mation shown on the DRB scan tool.
(4) To erase DTC's, use the ªErase Trouble Codeº
data screen on the DRB scan tool.Do not erase any
DTC's until problems have been investigated
and repairs have been performed.
DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
(G) Generator Lamp Illuminated
GENERIC SCAN
TOOL CODEDRB SCAN TOOL DISPLAY DESCRIPTION OF DIAGNOSTIC TROUBLE CODE
P0106 (M) Barometric Pressure Out of Range MAP sensor input voltage out of an acceptable range
detected during reading of barometric pressure at
key-on.
P0107 (M) Map Sensor Voltage Too Low MAP sensor input below minimum acceptable voltage.
P0108 (M) Map Sensor Voltage Too High MAP sensor input above maximum acceptable voltage.
P0112 (M) Intake Air Temp Sensor Voltage Low Intake air (charge) temperature sensor input below the
minimum acceptable voltage.
P0113 (M) Intake Air Temp Sensor Voltage
HighIntake air (charge) temperature sensor input above the
maximum acceptable voltage.
P0116 A rationatilty error has been detected in the coolant
temp sensor.
P0117 (M) ECT Sensor Voltage Too Low Engine coolant temperature sensor input below the
minimum acceptable voltage.
P0118 (M) ECT Sensor Voltage Too High Engine coolant temperature sensor input above the
maximum acceptable voltage.
P0121 (M) TPS Voltage Does Not Agree With
MAPTPS signal does not correlate to MAP sensor signal.
P0122 (M) Throttle Position Sensor Voltage
LowThrottle position sensor input below the acceptable
voltage range.
P0123 (M) Throttle Position Sensor Voltage
HighThrottle position sensor input above the maximum
acceptable voltage.
P0125 (M) Closed Loop Temp Not Reached Time to enter Closed Loop Operation (Fuel Control) is
excessive.
P0130 1/1 O2 Sensor Heater Relay Circuit An open or shorted condition detected in the ASD or
CNG shutoff relay control ckt.
P0131 (M) 1/1 O2 Sensor Shorted To Ground Oxygen sensor input voltage maintained below normal
operating range.
P0132 (M) 1/1 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normal
operating range.
P0133 (M) 1/1 O2 Sensor Slow Response Oxygen sensor response slower than minimum required
switching frequency.
25 - 6 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P0456 Evap Leak Monitor Small Leak
Detected
P0460 Fuel Level Unit No Change Over
MilesNo movement of fuel level sender detected.
P0461 Fuel Level Unit No Changeover
TimeNo level of fuel level sender detected.
P0462 Fuel Level Sending Unit Volts Too
LowFuel level sensor input below acceptable voltage.
P0463 Fuel Level Sending Unit Volts Too
HighFuel level sensor input above acceptable voltage.
P0500 (M) No Vehicle Speed Sensor Signal No vehicle speed sensor signal detected during road
load conditions.
P0505 (M) Idle Air Control Motor Circuits Replace
P0522 Oil Pressure Sens Low Oil pressure sensor input below acceptable voltage.
P0523 Oil Pressure Sens High Oil pressure sensor input above acceptable voltage.
P0551 (M) Power Steering Switch Failure Incorrect input state detected for the power steering
switch circuit. PL: High pressure seen at high speed.
P0600 (M) PCM Failure SPI Communications No communication detected between co-processors in
the control module.
P0601 (M) Internal Controller Failure Internal control module fault condition (check sum)
detected.
P0604 Internal Trans Controller Transmission control module RAM self test fault
detected. -Aisin transmission.
P0605 Internal Trans Controller Transmission control module ROM self test fault
detected -Aisin transmission.
P0622 (G) Generator Field Not Switching
ProperlyAn open or shorted condition detected in the generator
field control circuit.
P0645 A/C Clutch Relay Circuit An open or shorted condition detected in the A/C clutch
relay control circuit.
P0700 (M) EATX Controller DTC Present This SBEC III or JTEC DTC indicates that the EATX or
Aisin controller has an active fault and has illuminated
the MIL via a CCD (EATX) or SCI (Aisin) message. The
specific fault must be acquired from the EATX via CCD
or from the Aisin via ISO-9141.
P0703 (M) Brake Switch Stuck Pressed or
ReleasedIncorrect input state detected in the brake switch circuit.
(Changed from P1595).
P0711 Trans Temp Sensor, No Temp Rise
After StartRelationship between the transmission temperature and
overdrive operation and/or TCC operation indicates a
failure of the Transmission Temperature Sensor. OBD II
Rationality.
P0712 Trans Temp Sensor Voltage Too
LowTransmission fluid temperature sensor input below
acceptable voltage.
P0713 Trans Temp Sensor Voltage Too
HighTransmission fluid temperature sensor input above
acceptable voltage.
P0720 Low Output SPD Sensor RPM,
Above 15 MPHThe relationship between the Output Shaft Speed
Sensor and vehicle speed is not within acceptable
limits.
25 - 10 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P0740 (M) Torq Con Clu, No RPM Drop at
LockupRelationship between engine and vehicle speeds
indicated failure of torque convertor clutch lock-up
system (TCC/PTU sol).
P0743 Torque Converter Clutch Solenoid/
Trans Relay CircuitsAn open or shorted condition detected in the torque
converter clutch (part throttle unlock) solenoid control
circuit. Shift solenoid C electrical fault - Aisin
transmission
P0748 Governor Pressur Sol Control/Trans
Relay CircuitsAn open or shorted condition detected in the Governor
Pressure Solenoid circuit or Trans Relay Circuit in JTEC
RE transmissions.
P0751 O/D Switch Pressed (Lo) More
Than 5 MinutesOverdrive override switch input is in a prolonged
depressed state.
P0753 Trans 3-4 Shift Sol/Trans Relay
CircuitsAn open or shorted condition detected in the overdrive
solenoid control circuit or Trans Relay Circuit in JTEC
RE transmissions.
P0756 AW4 Shift Sol B (2-3) Functional
FailureShift solenoid B (2-3) functional fault - Aisin
transmission
P0783 3-4 Shift Sol, No RPM Drop at
LockupThe overdrive solenoid is unable to engage the gear
change from 3rd gear to the overdrive gear.
P0801 Reverse Gear Lockout Circuit Open
or ShortAn open or shorted condition detected in the
transmission reverse gear lock-out solenoid control
circuit.
P01192 Inlet Air Temp. Circuit Low Inlet Air Temp. sensor input below acceptable voltage
P01193 Inlet Air Temp. Circuit High Inlet Air Temp. sensor input above acceptable voltage.
P1195 (M) 1/1 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 1/1 during catalyst monitor test. (was P0133)
P1196 (M) 2/1 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 2/1 during catalyst monitor test. (was P0153)
P1197 1/2 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 1/2 during catalyst monitor test. (was P0139)
P1198 Radiator Temperature Sensor Volts
Too HighRadiator coolant temperature sensor input above the
maximum acceptable voltage.
P1199 Radiator Temperature Sensor Volts
Too LowRadiator coolant temperature sensor input below the
minimum acceptable voltage.
P1281 Engine is Cold Too Long Engine coolant temperature remains below normal
operating temperatures during vehicle travel
(Thermostat).
P1282 Fuel Pump Relay Control Circuit An open or shorted condition detected in the fuel pump
relay control circuit.
P1288 Intake Manifold Short Runner
Solenoid CircuitAn open or shorted condition detected in the short
runner tuning valve circuit.
P1289 Manifold Tune Valve Solenoid
CircuitAn open or shorted condition detected in the manifold
tuning valve solenoid control circuit.
P1290 CNG Fuel System Pressure Too
HighCompressed natural gas system pressure above normal
operating range.
P1291 No Temp Rise Seen From Intake
HeatersEnergizing Heated Air Intake does not change intake air
temperature sensor an acceptable amount.
PLEMISSION CONTROL SYSTEMS 25 - 11
DESCRIPTION AND OPERATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P1292 CNG Pressure Sensor Voltage Too
HighCompressed natural gas pressure sensor reading above
acceptable voltage.
P1293 CNG Pressure Sensor Voltage Too
LowCompressed natural gas pressure sensor reading below
acceptable voltage.
P1294 (M) Target Idle Not Reached Target RPM not achieved during drive idle condition.
Possible vacuum leak or IAC (AIS) lost steps.
P1295 No 5 Volts to TP Sensor Loss of a 5 volt feed to the Throttle Position Sensor has
been detected.
P1296 No 5 Volts to MAP Sensor Loss of a 5 volt feed to the MAP Sensor has been
detected.
P1297 (M) No Change in MAP From Start To
RunNo difference is recognized between the MAP reading
at engine idle and the stored barometric pressure
reading.
P1298 Lean Operation at Wide Open
ThrottleA prolonged lean condition is detected during Wide
Open Throttle.
P1299 (M) Vacuum Leak Found (IAC Fully
Seated)MAP Sensor signal does not correlate to Throttle
Position Sensor signal. Possible vacuum leak.
P1388 Auto Shutdown Relay Control
CircuitAn open or shorted condition detected in the ASD or
CNG shutoff relay control ckt.
P1389 No ASD Relay Output Voltage At
PCMNo Z1 or Z2 voltage sensed when the auto shutdown
relay is energized.
P1390 (M) Timing Belt Skipped 1 Tooth or
MoreRelationship between Cam and Crank signals not
correct.
P1391 (M) Intermittent Loss of CMP or CKP Loss of the Cam Position Sensor or Crank Position
sensor has occurred. For PL 2.0L
P1398 (M) Mis-Fire Adaptive Numerator at
LimitPCM is unable to learn the Crank Sensor's signal in
preparation for Misfire Diagnostics. Probable defective
Crank Sensor.
P1399 Wait To Start Lamp Cicuit An open or shorted condition detected in the Wait to
Start Lamp circuit.
P1403 No 5 Volts to EGR Sensor Loss of 5v feed to the EGR position sensor.
P1476 Too Little Secondary Air Insufficient flow of secondary air injection detected
during aspirator test.(was P0411)
P1477 Too Much Secondary Air Excessive flow of secondary air injection detected
during aspirator test (was P0411).
P1478 (M) Battery Temp Sensor Volts Out of
LimitInternal temperature sensor input voltage out of an
acceptable range.
P1479 Transmission Fan Relay Circuit An open or shorted condition detected in the
transmission fan relay circuit.
P1480 PCV Solenoid Circuit An open or shorted condition detected in the PCV
solenoid circuit.
P1482 Catalyst Temperature Sensor Circuit
Shorted LowCatalyst temperature sensor circuit shorted low.
P1483 Catalyst Temperature Sensor Circuit
Shorted High.Catalyst temperature sensor circuit shorted high.
P1484 Catalytic Converter Overheat
DetectedA catalyst overheat condition has been detected by the
catalyst temperature sensor.
25 - 12 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P1485 Air Injection Solenoid Circuit An open or shorted condition detected in the air assist
solenoid circuit.
P1486 (M) Evap Leak Monitor Pinched Hose
FoundLDP has detected a pinched hose in the evaporative
hose system.
P1487 Hi Speed Rad Fan CTRL Relay
CircuitAn open or shorted condition detected in the control
circuit of the #2 high speed radiator fan control relay.
P1488 Auxiliary 5 Volt Supply Output Too
LowAuxiliary 5 volt sensor feed is sensed to be below an
acceptable limit.
P1489 (M) High Speed Fan CTRL Relay Circuit An open or shorted condition detected in the control
circuit of the high speed radiator fan control relay.
P1490 (M) Low Speed Fan CTRL Relay Circuit An open or shorted condition detected in control circuit
of the low speed radiator fan control relay.
P1491 Rad Fan Control Relay Circuit An open or shorted condition detected in the radiator
fan control relay control circuit. This includes PWM solid
state relays.
P1492 (M,G) Ambient/Batt Temp Sen Volts Too
HighExternal temperature sensor input above acceptable
voltage.
P1493 (M,G) Ambient/Batt Temp Sen Volts Too
LowExternal temperature sensor input below acceptable
voltage.
P1494 (M) Leak Detection Pump Sw or
Mechanical FaultIncorrect input state detected for the Leak Detection
Pump (LDP) pressure switch.
P1495 (M) Leak Detection Pump Solenoid
CircuitAn open or shorted condition detected in the Leak
Detection Pump (LDP) solenoid circuit.
P1496 (M) 5 Volt Supply, Output Too Low 5 volt sensor feed is sensed to be below an acceptable
limit.(<4vfor4sec).
P1498 High Speed Rad Fan Ground CTRL
Rly CircuitAn open or shorted condition detected in the control
circuit of the #3 high speed radiator fan control relay.
P1594 (G) Charging System Voltage Too High Battery voltage sense input above target charging
voltage during engine operation.
P1595 Speed Control Solenoid Circuits An open or shorted condition detected in either of the
speed control vacuum or vent solenoid control circuits.
P1596 Speed Control Switch Always High Speed control switch input above maximum acceptable
voltage.
P1597 Speed Control Switch Always Low Speed control switch input below minimum acceptable
voltage.
P1598 A/C Pressure Sensor Volts Too High A/C pressure sensor input above maximum acceptable
voltage.
P1599 A/C Pressure Sensor Volts Too Low A/C pressure sensor input below minimum acceptable
voltage.
P1680 Clutch Released Switch Circuit
P1681 No I/P Cluster CCD/J1850
Messages ReceivedNo CCD/J1850 messages received from the cluster
control module.
P1682 (G) Charging System Voltage Too Low Battery voltage sense input below target charging
voltage during engine operation and no significant
change in voltage detected during active test of
generator output circuit.
P1683 SPD CTRL PWR Relay; or S/C 12v
Driver CKTAn open or shorted condition detected in the speed
control servo power control circuit. (SBECII: ext relay).
PLEMISSION CONTROL SYSTEMS 25 - 13
DESCRIPTION AND OPERATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P1684 The battery has been disconnected within the last 50
starts.
P1685 Skim Invalid Key The engine controler has received an invalid key from
the SKIM.
P1686 No SKIM BUS Messages Received No CCD/J1850 messages received from the Smart Key
Immobilizer Module (SKIM).
P1687 No MIC BUS Message No CCD/J1850 messages received from the Mechanical
Instrument Cluster (MIC) module.
P1693 DTC Detected in Companion
ModuleA fault has been generated in the companion engine
control module.
P1694 Fault In Companion Module No CCD/J1850 messages received from the powertrain
control module-Aisin transmission.
P1695 No CCD/J1850 Message From
Body Control ModuleNo CCD/J1850 messages received from the body
control module.
P1696 (M) PCM Failure EEPROM Write
DeniedUnsuccessful attempt to write to an EEPROM location
by the control module.
P1697 (M) PCM Failure SRI Mile Not Stored Unsuccessful attempt to update Service Reminder
Indicator (SRI or EMR) mileage in the control module
EEPROM.
P1698 (M) No CCD/J1850 Message From TCM No CCD/J1850 messages received from the electronic
transmission control module (EATX) or the Aisin
transmission controller.
P1719 Skip Shift Solenoid Circuit An open or shorted condition detected in the
transmission 2-3 gear lock-out solenoid control circuit.
P1756 GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control
System which is used to regulate governor pressure to
control shifts for 1st, 2nd, and 3rd gear. (Mid Pressure
Malfunction)
P1757 GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control
System which is used to regulate governor pressure to
control shifts for 1st, 2nd, and 3rd gear (Zero Pressure
Malfunction)
P1762 Gov Press Sen Offset Volts Too Lo
or HighThe Governor Pressure Sensor input is greater than a
calibration limit or is less than a calibration limit for 3
consecutive park/neutral calibrations.
P1763 Governor Pressure Sensor Volts
To o H iThe Governor Pressure Sensor input is above an
acceptable voltage level.
P1764 Governor Pressure Sensor Volts
Too LowThe Governor Pressure Sensor input is below an
acceptable voltage level.
P1765 Trans 12 Volt Supply Relay CTRL
CircuitAn open or shorted condition is detected in the
Transmission Relay control circuit. This relay supplies
power to the TCC>
P1899 (M) P/N Switch Stuck in Park or in Gear Incorrect input state detected for the Park/Neutral
switch.
25 - 14 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

MONITORED SYSTEMS
DESCRIPTION
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator (Check
Engine) Lamp will be illuminated. These monitors
generate Diagnostic Trouble Codes that can be dis-
played with the check engine lamp or a scan tool.
The following is a list of the monitored systems:
²EGR Monitor
²Misfire Monitor
²Fuel System Monitor
²Evaporative Emissions Monitor
Following is a description of each system monitor,
and its DTC.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
EGR MONITOR
The Powertrain Control Module (PCM) performs
an on-board diagnostic check of the EGR system.
The EGR system consists of two main components:
a vacuum solenoid back pressure transducer and a
vacuum operated valve. The EGR monitor is used to
test whether the EGR system is operating within
specifications. The diagnostic check activates only
during selected engine/driving conditions. When the
conditions are met, the EGR is turned off (solenoid
energized) and the O2S compensation control is mon-
itored. Turning off the EGR shifts the air fuel (A/F)
ratio in the lean direction. Oxygen sensor voltage
then indicates increased oxygen in the exhaust. Con-
sequently, Short Term Compensation shifts to rich
(increased injector pulse width). By monitoring the
shift, the PCM can indirectly monitor the EGR sys-
tem. While this test does not directly measure the
operation of the EGR system, it can be inferred from
the shift in the O2S data whether the EGR system is
operating correctly. Because the O2S is being used,
the O2S test must pass its test before the EGR test.
Enabling ConditionsÐ
²Engine Temperature
²Engine Run Time
²Engine RPM²MAP Sensor
²TPS
²Vehicle Speed
²Short Term Compensation
Pending ConditionsÐThe EGR Monitor does
not run when any of the following example faults
have illuminated the MIL:
²Misfire
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Fuel System Rich/Lean
²Limp in for MAP, TPS or ECT
²Vehicle Speed Sensor
²Cam or Crank Sensor
²EGR Electrical
²EVAP Electrical
²Fuel Injector
²Ignition Coil
²Idle Speed
²Engine Coolant Temperature (ECT)
²MAP Sensor
²Intake Air Temperature (IAT)
Conflict ConditionsÐThe EGR Monitor typi-
cally does not run if any of the following conditions
are present:
²Fuel System Monitor
²Purge Monitor
²Catalyst Monitor
²Low Fuel Level
²High Altitude
²Low Ambient Air Temperature
The EGR Monitor does not run if any of the follow-
ing example DTCs are present:
²Misfire Monitor, Priority 2
²Upstream Oxygen Sensor Heater, Priority 1
²Fuel System Monitor, Priority 2
²Oxygen Sensor Monitor, Priority 1
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
OBD II regulations for misfire monitoring require
two different tests for misfire. The first is a Catalyst
Damage level of misfire test. The second is for emis-
sions greater than 1.5 times the Federal Tailpipe
(FTP) standards. The tests are monitored by two dif-
ferent counters. These counters are:
PLEMISSION CONTROL SYSTEMS 25 - 15
DESCRIPTION AND OPERATION (Continued)