brake sensor DODGE TOWN AND COUNTRY 2001 Manual PDF

FLUID
STANDARD PROCEDURE - FLUID LEVEL AND
CONDITION CHECK
NOTE: Only transmission fluid of the type labeled
Mopar ATF+4 (Automatic Transmission Fluid±Type
9602) should be used in this transaxle.
FLUID LEVEL CHECK
The transmission sump has a fluid level indicator
(dipstick) to check oil similar to most automatic
transmissions. It is located on the left side of the
engine. Be sure to wipe all dirt from dipstick handle
before removing.
The torque converter fills in both the P Park and N
Neutral positions. Place the selector lever in P Park
to be sure that the fluid level check is accurate.The
engine should be running at idle speed for at
least one minute, with the vehicle on level
ground.At normal operating temperature (approxi-
mately 82 C. or 180 F.), the fluid level is correct if it
is in the HOT region (cross-hatched area) on the oil
level indicator (Fig. 214). The fluid level should be
within the WARM range of the dipstick at 70É F fluid
temperature.
FLUID LEVEL CHECK USING DRB
NOTE: Engine and Transaxle should be at normal
operating temperature before performing this proce-
dure.
(1) Start engine and apply parking brake.
(2) Hook up DRB scan tool and select transmis-
sion.(3) Select sensors.
(4) Read the transmission temperature value.
(5) Compare the fluid temperature value with the
fluid temperature chart (Fig. 215).
(6) Adjust transmission fluid level shown on the
indicator according to the chart.
(7) Check transmission for leaks.
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transaxle has too much fluid, the
gears churn up foam and cause the same conditions
which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transaxle vent where it may be mistaken
for a leak.
FLUID CONDITION
Along with fluid level, it is important to check the
condition of the fluid. When the fluid smells burned,
and is contaminated with metal or friction material
particles, a complete transaxle recondition is proba-
bly required. Be sure to examine the fluid on the dip-
stick closely. If there is any doubt about its condition,
drain out a sample for a double check.
Moparž ATF+4 (Automatic Transmission Fluid-
Type 9602) when new is red in color. The ATF is dyed
red so it can be identified from other fluids used in
the vehicle such as engine oil or antifreeze. The red
color is not permanent and is not an indicator of fluid
condition. As the vehicle is driven, the ATF will begin
to look darker in color and may eventually become
brown. This is normal. A dark brown/black fluid
accompanied with a burnt odor and/or deterioration
in shift quality may indicate fluid deterioration or
transmission component failure.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
STANDARD PROCEDURE - FLUID AND FILTER
SERVICE
NOTE: Refer to the maintenance schedules in
LUBRICATION and MAINTENANCE, or the vehicle
owner's manual, for the recommended maintenance
(fluid/filter change) intervals for this transaxle.
Fig. 214 Transaxle Fluid Level Indicator
1 - TRANSAXLE DIPSTICK
21 - 246 AUTOMATIC - 41TERS
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EMISSIONS CONTROL
TABLE OF CONTENTS
page page
EMISSIONS CONTROL
DESCRIPTION............................1
OPERATION.............................8EVAPORATIVE EMISSIONS.................10
EXHAUST GAS RECIRCULATION............20
ON-BOARD DIAGNOSTICS.................23
EMISSIONS CONTROL
DESCRIPTION - MONITORED COMPONENT
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (Check Engine) will illuminate.
Some of the component monitors are checking for
proper operation of the part. Electrically operated
components now have input (rationality) and output
(functionality) checks. Previously, a component like
the Throttle Position sensor (TPS) was checked by
the PCM for an open or shorted circuit. If one of
these conditions occurred, a DTC was set. Now there
is a check to ensure that the component is working.
This is done by watching for a TPS indication of a
greater or lesser throttle opening than MAP and
engine rpm indicate. In the case of the TPS, if engine
vacuum is high and engine rpm is 1600 or greater
and the TPS indicates a large throttle opening, a
DTC will be set. The same applies to low vacuum
and 1600 rpm.Any component that has an associated
limp in will set a fault after 1 trip with the malfunc-
tion present.
Refer to the Diagnostic Trouble Codes Description
Charts in this section and the appropriate Power-
train Diagnostic Procedure Manual for diagnostic
procedures.
The following is a list of the monitored compo-
nents:
²Comprehensive Components
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
COMPREHENSIVE COMPONENTS
Along with the major monitors, OBD II requires
that the diagnostic system monitor any component
that could affect emissions levels. In many cases,
these components were being tested under OBD I.
The OBD I requirements focused mainly on testing
emissions-related components for electrical opens and
shorts.However, OBD II also requires that inputs from
powertrain components to the PCM be tested for
rationality, and that outputs to powertrain compo-
nents from the PCM be tested forfunctionality.
Methods for monitoring the various Comprehensive
Component monitoring include:
(1) Circuit Continuity
²Open
²Shorted high
²Shorted to ground
(2) Rationality or Proper Functioning
²Inputs tested for rationality
²Outputs tested for functionality
NOTE: Comprehensive component monitors are
continuous. Therefore, enabling conditions do not
apply.
Input RationalityÐWhile input signals to the
PCM are constantly being monitored for electrical
opens and shorts, they are also tested for rationality.
This means that the input signal is compared against
other inputs and information to see if it makes sense
under the current conditions.
PCM sensor inputs that are checked for rationality
include:
²Manifold Absolute Pressure (MAP) Sensor
²Oxygen Sensor (O2S)
²Engine Coolant Temperature (ECT) Sensor
²Camshaft Position (CMP) Sensor
²Vehicle Speed Sensor
²Crankshaft Position (CKP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Ambient/Battery Temperature Sensors
²Power Steering Switch
²Oxygen Sensor Heater
²Engine Controller
²Brake Switch
²Leak Detection Pump Switch
²P/N Switch
²Trans Controls
Output FunctionalityÐPCM outputs are tested
for functionality in addition to testing for opens and
shorts. When the PCM provides a voltage to an out-
RSEMISSIONS CONTROL25-1
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PCM calculates the A/F mixture from the output of
the O2S. A low voltage indicates high oxygen content
(lean mixture). A high voltage indicates a low content
of oxygen (rich mixture).
When the upstream O2S detects a lean condition,
there is an abundance of oxygen in the exhaust gas.
A functioning converter would store this oxygen so it
can use it for the oxidation of HC and CO. As the
converter absorbs the oxygen, there will be a lack of
oxygen downstream of the converter. The output of
the downstream O2S will indicate limited activity in
this condition.
As the converter loses the ability to store oxygen,
the condition can be detected from the behavior of
the downstream O2S. When the efficiency drops, no
chemical reaction takes place. This means the con-
centration of oxygen will be the same downstream as
upstream. The output voltage of the downstream
O2S copies the voltage of the upstream sensor. The
only difference is a time lag (seen by the PCM)
between the switching of the O2S's.
To monitor the system, the number of lean-to-rich
switches of upstream and downstream O2S's is
counted. The ratio of downstream switches to
upstream switches is used to determine whether the
catalyst is operating properly. An effective catalyst
will have fewer downstream switches than it has
upstream switches i.e., a ratio closer to zero. For a
totally ineffective catalyst, this ratio will be one-to-
one, indicating that no oxidation occurs in the device.
The system must be monitored so that when cata-
lyst efficiency deteriorates and exhaust emissions
increase to over the legal limit, the MIL (check
engine lamp) will be illuminated.
Monitor OperationÐTo monitor catalyst effi-
ciency, the PCM expands the rich and lean switch
points of the heated oxygen sensor. With extended
switch points, the air/fuel mixture runs richer and
leaner to overburden the catalytic converter. Once
the test is started, the air/fuel mixture runs rich and
lean and the O2 switches are counted. A switch is
counted when an oxygen sensor signal goes from
below the lean threshold to above the rich threshold.
The number of Rear O2 sensor switches is divided by
the number of Front O2 sensor switches to determine
the switching ratio.
The test runs for 20 seconds. As catalyst efficiency
deteriorated over the life of the vehicle, the switch
rate at the downstream sensor approaches that of the
upstream sensor. If at any point during the test
period the switch ratio reaches a predetermined
value, a counter is incremented by one. The monitor
is enabled to run another test during that trip. When
the test fails three times, the counter increments to
three, a malfunction is entered, and a Freeze Frame
is stored. When the counter increments to three dur-ing the next trip, the code is matured and the MIL is
illuminated. If the test passes the first, no further
testing is conducted during that trip.
The MIL is extinguished after three consecutive
good trips. The good trip criteria for the catalyst
monitor is more stringent than the failure criteria. In
order to pass the test and increment one good trip,
the downstream sensor switch rate must be less than
80% of the upstream rate (60% for manual transmis-
sions). The failure percentages are 90% and 70%
respectively.
Enabling ConditionsÐThe following conditions
must typically be met before the PCM runs the cat-
alyst monitor. Specific times for each parameter may
be different from engine to engine.
²Accumulated drive time
²Enable time
²Ambient air temperature
²Barometric pressure
²Catalyst warm-up counter
²Engine coolant temperature
²Accumulated throttle position sensor
²Vehicle speed
²MAP
²RPM
²Engine in closed loop
²Fuel level
Pending ConditionsÐ
²Misfire DTC
²Front Oxygen Sensor Response
²Front Oxygen Sensor Heater Monitor
²Front Oxygen Sensor Electrical
²Rear Oxygen Sensor Rationality (middle check)
²Rear Oxygen Sensor Heater Monitor
²Rear Oxygen Sensor Electrical
²Fuel System Monitor
²All TPS faults
²All MAP faults
²All ECT sensor faults
²Purge flow solenoid functionality
²Purge flow solenoid electrical
²All PCM self test faults
²All CMP and CKP sensor faults
²All injector and ignition electrical faults
²Idle Air Control (IAC) motor functionality
²Vehicle Speed Sensor
²Brake switch
²Intake air temperature
ConflictÐThe catalyst monitor does not run if any
of the following are conditions are present:
²EGR Monitor in progress
²Fuel system rich intrusive test in progress
²EVAP Monitor in progress
²Time since start is less than 60 seconds
²Low fuel level
²Low ambient air temperature
25 - 4 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)
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EXHAUST GAS RECIRCULATION
TABLE OF CONTENTS
page page
EXHAUST GAS RECIRCULATION
DESCRIPTION............................3
OPERATION.............................3
VA LV E
DESCRIPTION............................3
OPERATION.............................4REMOVAL...............................4
INSTALLATION............................4
VALVE COOLER
DESCRIPTION............................4
REMOVAL...............................4
INSTALLATION............................5
EXHAUST GAS
RECIRCULATION
DESCRIPTION
The EGR system reduces oxides of nitrogen (NOx)
in the engine exhaust. This is accomplished by allow-
ing a predetermined amount of hot exhaust gas to
recirculate and dilute the incoming fuel/air mixture.
A malfunctioning EGR system can cause engine
stumble, sags, or hesitation, rough idle, engine stall-
ing and poor driveability.
OPERATION
The system consists of:
²An EGR valve assembly. The valve is located on
the rear of the engine above the exhaust manfiold.
²An EGR solenoid.The EGR solenoid controls the
ªon timeº of the EGR valve.
²The ECM operates the EGR solenoid. The ECM
is located inside the vehicle under the instrument
panel.
²An EGR tube connects a passage in the EGR
valve to the rear of the exhaust manifold.
²The vacuum pump supplies vacuum for the EGR
solenoid and the EGR valve. This pump also supplies
vacuum for operation of the power brake boosterb
and the heating and air conditioning system. The
pump is located internally in the front of the engine
block and is driven by the crankshaft gear.
²Vacuum lines and hoses connect the various
components.
When the ECM supplies a variable ground signal
to the EGR solenoid, EGR system operation starts to
occur. The ECM will monitor and determine when tosupply and remove this variable ground signal. This
will depend on inputs from the engine coolant tem-
perature, throttle position and engine speed sensors.
When the variable ground signal is supplied to the
EGR solenoid, vacuum from the vacuum pump will
be allowed to pass through the EGR solenoid and on
to the EGR valve with a connecting hose.
Exhaust gas recirculation will begin in this order
when:
²The ECM determines that EGR system opera-
tion is necessary.
²The engine is running to operate the vacuum
pump.
²A variable ground signal is supplied to the EGR
solenoid.
²Variable vacuum passes through the EGR sole-
noid to the EGR valve.
²The inlet seat (poppet valve) at the bottom of
the EGR valve opens to dilute and recirculate
exhaust gas back into the intake manifold.
The EGR system will be shut down by the ECM
after 60 seconds of continuous engine idling to
improve idle quality.
VA LV E
DESCRIPTION
The EGR system consists of (Fig. 1):
²EGR valve
²EGR tube
²Vacuum hoses
²EGR cooler
²EGR solenoid
RGEXHAUST GAS RECIRCULATION25a-3
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Generic Scan Tool Code DRB IIITScan Tool Display
P1703 Brake Switch Signal CKTS Plaus. With Redundant Contact After
Initialization
P2120 Acc. Pedal Position Sensor 1 CKT Plausibility
Acc. Pedal Position Sensor 1 CKT Plausibility With Brake Switch
Acc. Pedal Position Sensor 1 CKT Plausibility With Potentiometer
Acc. Pedal Position Sensor 1 CKT Signal Voltage Too High
Acc. Pedal Position Sensor 1 CKT Signal Voltage Too Low
Acc. Pedal Position Sensor 1 CKT Signal Voltage Too High or Low
25a - 10 ON-BOARD DIAGNOSTICSRG
ON-BOARD DIAGNOSTICS (Continued)
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