2002 CHRYSLER CARAVAN air condition

Long Term
The second fuel correction program is the long
term adaptive memory. In order to maintain correct
emission throughout all operating ranges of the
engine, a cell structure based on engine rpm and load
(MAP) is used.
Ther number of cells varies upon the driving con-
ditions. Two cells are used only during idle, based
upon TPS and Park/Neutral switch inputs. There
may be two other cells used for deceleration, based
on TPS, engine rpm, and vehicle speed. The other
twelve cells represent a manifold pressure and an
rpm range. Six of the cells are high rpm and the
other six are low rpm. Each of these cells is a specific
MAP voltage range Typical Adaptive Memory Fuel
Cells .
As the engine enters one of these cells the PCM
looks at the amount of short term correction being
used. Because the goal is to keep short term at 0 (O2
Sensor switching at 0.5 volt), long term will updatein the same direction as short term correction was
moving to bring the short term back to 0. Once short
term is back at 0, this long term correction factor is
stored in memory.
The values stored in long term adaptive memory
are used for all operating conditions, including open
loop and cold starting. However, the updating of the
long term memory occurs after the engine has
exceeded approximately 170É-190É F, with fuel control
in closed loop and two minutes of engine run time.
This is done to prevent any transitional temperature
or start-up compensations from corrupting long term
fuel correction.
Long term adaptive memory can change the pulse-
width by as much as 25%, which means it can correct
for all of short term. It is possible to have a problem
that would drive long term to 25% and short term to
another 25% for a total change of 50% away from
base pulse-width calculation.
TYPICAL ADAPTIVE MEMORY FUEL CELLS
Open
ThrottleOpen
ThrottleOpen
ThrottleOpen
ThrottleOpen
ThrottleOpen
Throttle Idle Decel
Vacuum 20 17 13 9 5 0
Above 1,984
rpm1 3 5 7 9 11 13 Drive 15
Below 1,984
rpm02 4 6 8 1012
Neutral14
MAP volt =0 1.4 2.0 2.6 3.3 3.9
Fuel Correction Diagnostics
There are two fuel correction diagnostic routines:
²Fuel System Rich
²Fuel System Lean
A DTC is set and the MIL is illuminated if the
PCM detects either of these conditions. This is deter-
mined based on total fuel correction, short term
times long term.
PROGRAMMABLE COMMUNICATIONS
INTERFACE (PCI) BUS
DESCRIPTION
The Programmable Communication Interface Mul-
tiplex system (PCI Bus) consist of a single wire. The
Body Control Module (BCM) acts as a splice to con-
nect each module and the Data Link Connector
(DLC) together. Each module is wired in parallel to
the data bus through its PCI chip set and uses its
ground as the bus reference. The wiring is a mini-
mum 20 gage wire.
OPERATION
Various modules exchange information through a
communications port called the PCI Bus. The Power-
train Control Module (PCM) transmits the Malfunc-
tion Indicator Lamp (Check Engine) On/Off signal
and engine RPM on the PCI Bus. The PCM receives
the Air Conditioning select input, transaxle gear
position inputs over the PCI Bus. The PCM also
receives the air conditioning evaporator temperature
signal from the PCI Bus.
The following components access or send informa-
tion on the PCI Bus.
²Instrument Panel
²Body Control Module
²Air Bag System Diagnostic Module
²Full ATC Display Head (if equipped)
²ABS Module
²Transmission Control Module
²Powertrain Control Module
²Travel Module
²SKIM
14 - 20 FUEL INJECTIONRS
FUEL INJECTION (Continued)
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OPERATION
The Transmission Control Module (TCM) supplies
the road speed and distance traveled inputs to the
PCM. From these inputs and the throttle position
sensor input, the PCM determines when a decelera-
tion condition occurs.
FUEL INJECTOR
DESCRIPTION
The injectors are positioned in the intake manifold
or cylinder head with the nozzle ends directly above
the intake valve port (Fig. 9).
OPERATION
The fuel injectors are 12 volt electrical solenoids
(Fig. 10). The injector contains a pintle that closes off
an orifice at the nozzle end. When electric current is
supplied to the injector, the armature and needle
move a short distance against a spring, allowing fuel
to flow out the orifice. Because the fuel is under high
pressure, a fine spray is developed in the shape of a
hollow cone or two streams. The spraying action
atomizes the fuel, adding it to the air entering the
combustion chamber. Fuel injectors are not inter-
changeable between engines.
The PCM provides battery voltage to each injector
through the ASD relay. Injector operation is con-
trolled by a ground path provided for each injector by
the PCM. Injector on-time (pulse-width) is variable,
and is determined by the PCM processing all the
data previously discussed to obtain the optimum
injector pulse width for each operating condition. Thepulse width is controlled by the duration of the
ground path provided.
REMOVAL
REMOVAL - 2.4L
The fuel rail must be removed first (Fig. 11). Refer
to Fuel Rail Removal in this section.
(1) Disconnect injector wiring connector from injec-
tor.
(2) Position fuel rail assembly so that the fuel
injectors are easily accessible (Fig. 12).
(3) Rotate injector and pull injector out of fuel rail.
The clip will stay on the injector.
(4) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. If injector is reused, a
protective cap must be installed on the injector tip to
Fig. 9 Fuel Injector Location - Typical
1 - FUEL RAIL
2 - INTAKE MANIFOLD
3 - FUEL INJECTORS
Fig. 10 FUEL INJECTOR - TYPICAL
1 - FUEL INJECTOR
2 - NOZZLE
3 - TOP (FUEL ENTRY)
Fig. 11 FUEL RAIL AND INJECTORS 2.4L
1 - Fuel Injectors
2 - Fuel Rail
RSFUEL INJECTION14-25
ENGINE SPEED SENSOR (Continued)
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FUEL PUMP RELAY
DESCRIPTION
The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.
OPERATION
The fuel pump relay supplies battery voltage to the
fuel pump. A buss bar in the Power Distribution Cen-
ter (PDC) supplies voltage to the solenoid side and
contact side of the relay. The fuel pump relay power
circuit contains a fuse between the buss bar in the
PDC and the relay. The fuse is located in the PDC.
Refer to the Wiring Diagrams for circuit information.
The PCM controls the fuel pump relay by switch-
ing the ground path for the solenoid side of the relay
on and off. The PCM turns the ground path off when
the ignition switch is in the Off position. When the
ignition switch is in the On position, the PCM ener-
gizes the fuel pump. If the crankshaft position sensor
does not detect engine rotation, the PCM de-ener-
gizes the relay after approximately one second.
IDLE AIR CONTROL MOTOR
DESCRIPTION
The idle air control motor is mounted on the throt-
tle body. The PCM operates the idle air control motor
(Fig. 14) or (Fig. 15).
OPERATION
The PCM adjusts engine idle speed through the
idle air control motor to compensate for engine load,
coolant temperature or barometric pressure changes.
The throttle body has an air bypass passage that
provides air for the engine during closed throttle idle.
The idle air control motor pintle protrudes into the
air bypass passage and regulates air flow through it.
The PCM adjusts engine idle speed by moving the
IAC motor pintle in and out of the bypass passage. The
adjustments are based on inputs the PCM receives.
The inputs are from the throttle position sensor, crank-
shaft position sensor, coolant temperature sensor, MAP
sensor, vehicle speed sensor and various switch opera-
tions (brake, park/neutral, air conditioning).
When engine rpm is above idle speed, the IAC is
used for the following functions:
²Off-idle dashpot
²Deceleration air flow control
²A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
Target Idle
Target idle is determined by the following inputs:
²Gear position
²ECT Sensor
²Battery voltage
²Ambient/Battery Temperature Sensor
²VSS
²TPS
²MAP Sensor
Fig. 14 TPS/IAC 2.4L
1 - Idle Air Control Motor
2 - Throttle Position Sensor
Fig. 15 TPS/IAC 3.3/3.8L
1 - Idle Air Control Motor
2 - Throttle Position Sensor
RSFUEL INJECTION14-27
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age will be higher at colder temperatures and is
gradually reduced at warmer temperatures.
The battery temperature information is also used
for OBD II diagnostics. Certain faults and OBD II
monitors are either enabled or disabled depending
upon the battery temperature sensor input (example:
disable purge, enable LDP). Most OBD II monitors
are disabled below 20ÉF.
MAP SENSOR
DESCRIPTION
The MAP sensor (Fig. 18) or (Fig. 19) mounts to
the intake manifold. The sensor is connects electri-
cally to the PCM.
OPERATION
The MAP serves as a PCM input, using a silicon
based sensing unit, to provide data on the manifold
vacuum that draws the air/fuel mixture into the com-
bustion chamber. The PCM requires this information
to determine injector pulse width and spark advance.
When MAP equals Barometric pressure, the pulse
width will be at maximum.
Also like the cam and crank sensors, a 5 volt ref-
erence is supplied from the PCM and returns a volt-
age signal to the PCM that reflects manifold
pressure. The zero pressure reading is 0.5V and full
scale is 4.5V. For a pressure swing of0Ð15psithe
voltage changes 4.0V. The sensor is supplied a regu-
lated 4.8 to 5.1 volts to operate the sensor. Like the
cam and crank sensors ground is provided through
the sensor return circuit.
The MAP sensor input is the number one contrib-
utor to pulse width. The most important function of
the MAP sensor is to determine barometric pressure.
The PCM needs to know if the vehicle is at sea level
or is it in Denver at 5000 feet above sea level,
because the air density changes with altitude. It will
also help to correct for varying weather conditions. If
a hurricane was coming through the pressure would
be very, very low or there could be a real fair
weather, high pressure area. This is important
because as air pressure changes the barometric pres-
sure changes. Barometric pressure and altitude have
a direct inverse correlation, as altitude goes up baro-
metric goes down. The first thing that happens as
the key is rolled on, before reaching the crank posi-
tion, the PCM powers up, comes around and looks at
the MAP voltage, and based upon the voltage it sees,
it knows the current barometric pressure relative to
altitude. Once the engine starts, the PCM looks at
the voltage again, continuously every 12 milliseconds,
and compares the current voltage to what it was at
key on. The difference between current and what it
was at key on is manifold vacuum.
During key On (engine not running) the sensor
reads (updates) barometric pressure. A normal range
can be obtained by monitoring known good sensor in
you work area.
As the altitude increases the air becomes thinner
(less oxygen). If a vehicle is started and driven to a
very different altitude than where it was at key On
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open throttle, based upon
TPS angle and RPM it will update barometric pres-
sure in the MAP memory cell. With periodic updates,
the PCM can make its calculations more effectively.
The PCM uses the MAP sensor to aid in calculat-
ing the following:
²Barometric pressure
²Engine load
Fig. 18 MAP SENSOR - 2.4L
Fig. 19 MAP SENSOR - 3.3/3.8L
RSFUEL INJECTION14-29
INLET AIR TEMPERATURE SENSOR (Continued)
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INSTALLATION - UPSTREAM 1/1 - 3.3/3.8L
The engines uses two heated oxygen sensors.
(1) 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 Loctite
771- 64 or equivalent. New sensors have compound
on the threads and do not require an additional coat-
ing.
(2) Install sensor and tighten to 27 N´m (20 ft.
lbs.).
(3) Connect the electrical connector for the O2 sen-
sor and install onto bracket.
(4) Connect the electrical connector for the speed
control servo.
(5) Install the speed control servo and bracket
refer to the Speed Control Servo for more informa-
tion.
(6) Connect the speed control vacuum harness to
servo.
(7) Install the battery tray, refer to the Battery
section for more information.
(8) Install battery, refer to the Battery section for
more information.
INSTALLATION DOWNSTREAM 2/1 -
2.4/3.3/3.8L
The O2S is located on the side of the catalytic con-
verter.
Threads of new oxygen sensors are factory coated
with anti-seize compound to aid in removal.DONOT add any additional anti-seize compound to
the threads of a new oxygen sensor.
(1) Install sensor and tighten to 27 N´m (20 ft.
lbs.).
(2) Connect the electrical connector.
(3) Lower vehicle.
(4) Install the negative battery cable.
THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold
(Fig. 26) or (Fig. 27). Fuel does not enter the intake
manifold through the throttle body. Fuel is sprayed
into the manifold by the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle body linkage arm.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
Fig. 25 DOWNSTREAM 2/1 O2 SENSOR
Fig. 26 IAC MOTOR 2.4L
1 - Idle Air Control Motor
2 - Throttle Position Sensor
RSFUEL INJECTION14-33
O2 SENSOR (Continued)
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THROTTLE POSITION SENSOR
DESCRIPTION
The throttle position sensor mounts to the side of
the throttle body (Fig. 28) or (Fig. 29).The sensor
connects to the throttle blade shaft. The TPS is a
variable resistor that provides the Powertrain Con-
trol Module (PCM) with an input signal (voltage).
OPERATION
The signal represents throttle blade position. As
the position of the throttle blade changes, the resis-
tance of the TPS changes.
The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
powertrain control module) represents throttle blade
position. The TPS output voltage to the PCM varies
from approximately 0.6 volt at minimum throttle
opening (idle) to a maximum of 4.5 volts at wide open
throttle.
Along with inputs from other sensors, the PCM
uses the TPS input to determine current engine oper-
ating conditions. The PCM also adjusts fuel injector
pulse width and ignition timing based on these
inputs.
REMOVAL - 3.3/3.8L
(1) Disconnect the negative battery cable.
(2) Remove the electrical connector from the Inlet
Air Temperature sensor.(3) Remove the air cleaner box lid. Remove hose
from throttle body.
(4) Disconnect the electrical connector at TPS.
(5) Disconnect the electrical connector at IAC.
(6) Remove the throttle and speed control cables
from throttle body.
(7) Remove 3 mounting bolts from throttle body.
(8) Remove throttle body.
(9) Disconnect the purge vacuum line from the
throttle body.
(10) Remove TPS from throttle body.
INSTALLATION - 3.3/3.8L
(1) Install TPS to throttle body.
(2) Disconnect the purge vacuum line from the
throttle body.
(3) Install throttle body.
(4) Install 3 mounting bolts from throttle body.
Tighten bolts.
(5) Install the throttle and speed control cables to
throttle body.
(6) Connect the electrical connector at TPS.
(7) Connect the electrical connector at IAC.
(8) Install the air cleaner box lid. Install hose to
throttle body.
(9) Install the electrical connector to the Inlet Air
Temperature sensor.
(10) Connect the negative battery cable.
Fig. 28 Throttle Position SensorÐ2.4L Engine
1 - Idle Air Control Motor
2 - Throttle Position Sensor
Fig. 29 Throttle Position SensorÐ3.3/3.8L Engine
1 - Idle Air Control Motor
2 - Throttle Position Sensor
RSFUEL INJECTION14-35
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(6) Start engine and let idle just long enough to
circulate power steering fluid through the analyzer
and hoses. Shut off engine.
(7) Check power steering fluid level and add fluid
as necessary. Start engine again and let idle until the
air is out of the fluid.
(8) Gauge should read below 300 psi (2068 kPa). If
above, inspect the hoses for restrictions and repair as
necessary. The initial pressure should be in the range
of 100-275 psi (689-1896 kPa) depending on fluid
temperature. The flow meter should read above 1.5
GPM.
CAUTION: The following test procedure involves
testing maximum pump pressure output and flow
control valve operation. Do not leave valve closed
for more than four seconds as the pump could be
damaged.
NOTE: Power steering pump maximum pressure for
2.4L engines is 1,200 ± 1,350 psi (8,274 ± 9,308
kPa). Power steering pump maximum pressure for
all other engines is 1,400 ± 1,500 psi (9,653 ± 10,342
kPa).
(9) Close analyzer valve fully three times and
record highest pressure indicated each time. All three
readings must be within specifications. If any of the
three power steering pump pressures are above orbelow specifications, replace pump. (Refer to 19 -
STEERING/PUMP - REMOVAL)
CAUTION: Do not force the steering to operate
against the stops for more than 4 seconds at a time
because pump damage can result.
(10) Once the pump has been verified as working
correctly, completely open the valve on the Power
Steering Analyzer. Turn the steering wheel to the
extreme left until the stop in the steering gear is
met. Hold it there for 2±4 seconds, then release it.
Now turn the steering wheel to the right until the
right stop is met. Hold it there for 2±4 seconds, then
release it. Record the stabilized pressure at each
position. Compare the recorded readings to the spec-
ifications. If the output pressures are not within 100
psi (689 kPa) of one another against either stop or
are below specifications, the steering gear is leaking
internally and must be replaced. (Refer to 19 -
STEERING/GEAR - REMOVAL)
DIAGNOSIS AND TESTING - STEERING
SYSTEM DIAGNOSIS CHARTS
NOTE: There are three diagnosis charts following
that cover POWER STEERING NOISE, STEERING
WHEEL FEEL, and POWER STEERING FLUID.
POWER STEERING NOISE
CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONABLE HISS
OR WHISTLE*1. Damaged or mispositioned
steering column shaft/coupling dash
panel seal.1. Reposition or replace steering
column shaft/coupling dash panel seal.
2. Noisy valve in power steering
gear.2. Replace power steering gear.
3. Mis-routed power steering hose. 3. Check routing of power steering
hoses. Ensure hoses do not come in
unwanted contact with other
components and objects.
RATTLE OR EXCESSIVE
CLUNK**1. Power steering gear loose on front
suspension crossmember.1. Inspect power steering gear
mounting bolts. Replace as necessary.
Tighten to the specified torque.
2. Front suspension crossmember
mounting fasteners loose at frame.2. Tighten the front suspension
crossmember mounting fasteners to the
specified torque.
3. Loose tie rod (outer or inner). 3. Check tie rod pivot points for wear.
Replace worn/loose parts as required.
RSSTEERING19-3
STEERING (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
4. Loose lower control arm mounting
bolts at front suspension
crossmember.4. Tighten control arm mounting bolts to
the specified torques.
5. Lower control arm pivot bushing
worn.5. Replace lower control arm pivot
bushing.
6. Loose strut assembly mounting
fasteners at tower or knuckle.6. Tighten strut assembly fasteners to
the specified torque.
7. Power steering fluid hose touching
the body of the vehicle.7. Adjust hose to proper position by
loosening, repositioning, and tightening
attachments to specified torque. Do not
bend tubing.
8. Internal power steering gear
noise.8. Replace power steering gear.
9. Damaged front suspension
crossmember.9. Replace front suspension
crossmember.
10. Stabilizer bar link ball joints
worn.10. Replace stabilizer bar link.
11. Lug nuts loose. 11. Tighten lug nuts to specifications.
12. Excessive Wheel bearing
free-play.12. Verify correct driveshaft hub nut
torque. Replace bearing if torque is
okay.
POPPING NOISE 1. Worn outer tie rod. 1. Check ball joint for free-play;
Replace outer tie rod.
2. Loose inner tie rod. 2. Replace power steering gear.
CHIRP OR SQUEAL
(POWER STEERING
PUMP)1. Loose power steering pump drive
belt.1. Check and adjust power steering
pump drive belt to specifications or
replace automatic tensioner where
applicable. Replace belt if worn or
glazed.
2. Malfuctioning belt auto-tensioner 2. Replace belt auto-tensioner.
WHINE, GROWL, MOAN
OR GROAN (POWER
STEERING PUMP)***1. Low fluid level. 1. Fill power steering fluid reservoir to
proper level and check for leaks (make
sure all air is bled from the system
fluid).
2. Power steering hose touching
vehicle body or frame.2. Adjust hose to proper position by
loosening, repositioning, and tightening
fitting to specified torque. Do not bend
tubing. Replace hose if damaged.
3. Extreme wear of power steering
pump internal components.3. Replace power steering pump and
flush system as necessary.
4. Extremely low ambient
temperature.4. Some noise can be expected, but will
go away as vehicle warms. Replace
pump if noise is excessive.
SUCKING AIR SOUND 1. Loose clamp on power steering
fluid return hose.1. Tighten or replace hose clamp.
2. Missing O-Ring on power steering
hose connection.2. Inspect connection and replace
O-Ring as required.
19 - 4 STEERINGRS
STEERING (Continued)
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