change time CHRYSLER VOYAGER 2004 Owner's Guide

brushes inside the motor. The current flow is con-
trolled by the multi-function switch. The high speed/
low speed relays are located in the IPM. The speed
sensitive intermittent wiper is controlled by the Body
Control Module (BCM). The intermittent mode, with
the vehicle traveling greater than 10.4 mph, has a
range of 0.5 to 18 seconds. With the vehicle traveling
less than 10.4 mph, the time delay doubles to a
range of 1 to 36 seconds. The wiper arms will park at
the base of the windshield just above the cowl cover
after the wiper switch is turned OFF.
The windshield wiper motor and linkage is located
in an integral wiper unit at the rear of the engine
compartment. The wiper unit must be removed to
gain access to the wiper motor.
REAR WIPER/WASHER SYSTEM
When rear wiper operation is required, the BCM
will provide ignition ON voltage to the rear wiper
motor (Export and ATC equipped vehicles only).
When the wiper switch is turned OFF, the BCM pro-
vides circuit ground to operate the motor until the
wipe cycle is complete and the wiper arm returns to
the base of the rear window.
Switch only offers an intermittent rear wiper
mode. The wiper motor will cycle every 7 seconds.
The intermittent delay time is also adjusted based
upon vehicle speed. With the vehicle traveling
greater than 50 mph, the cycle changes to every 5
seconds.
When rear washer is requested by depressing and
holding down the switch, the BCM then provides a
ground for the rear washer motor. Until the switch is
released, the motor will be in a continuous wipe
mode, then return to an intermittent wipe mode.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FRONT WIPER
SYSTEM
The windshield wiper system operates in several
modes:
²Low and high speed normal wipe
²Speed sensitive intermittent wipe
²Wipe after wash
²Park (switch OFF)
The windshield wiper circuits are continuously
monitored and controlled by the Body Control Mod-
ule (BCM). If a problem occurs in the electronic com-
ponents, wiring, switch (except integral motor park
switch) and wiper motor a Diagnostic Trouble Code
(DTC) will be stored in the BCM memory. DTC's can
be retrieved using a DRB IIItscan tool. Refer to the
proper Body Diagnostic Procedures manual for DTC
descriptions and retrieval information.The windshield wiper park switch and circuit is
monitored by the BCM. The park switch and circuit
can be tested using the Wiper System Diagnosis
table.
DIAGNOSIS AND TESTING - FRONT
WIPER/WASHER SWITCH
(1) Remove the multi-function switch (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
MULTI-FUNCTION SWITCH - REMOVAL).
(2) Using an ohmmeter check resistance readings
between switch pins. Refer to the WIPER/WASHER
SWITCH RESISTANCE table.
WIPER/WASHER SWITCH RESISTANCE
SWITCH POSITION RESISTANCE BETWEEN
OFF 1 AND 2 = 23.9KV 5%
DELAY POSITION
1ST 1 AND 2 = 7.9KV 5%
2ND 1 AND 2 = 4.6KV 5%
3RD 1 AND 2 = 2.9KV 5%
4TH 1 AND 2 = 1.9KV 5%
5TH 1 AND 2 = 1.3KV 5%
LOW 1 AND 2 = 670V 5%
HIGH 1 AND2=240V 5%
WASH 1 AND 4 = 5.9KV 5%
DIAGNOSIS AND TESTING - FAILED PARK
SWITCH
If the wiper park switch has failed, the windshield
wipers will operate as follows:
²SWITCH OFF- Wipers stop in current location
regardless of the park signal.
²INTERMITTENT MODE- Wipers operate con-
tinuously or at low speed for one or more extra
wipes.
²LOW SPEED- Wipers operate at low speed.
²HIGH SPEED- Wipers operate at high speed.
²WIPE AFTER WASH- Wipers operate at low
speed in any mode setting. Wipers operate only while
the wash button is depressed with switch in the OFF
mode and wipers stop in mid-cycle when button is
released.
The windshield wiper park switch and circuit is
monitored by the BCM. The park switch and circuit
can be tested using the WIPER SYSTEM DIAGNO-
SIS table.
8R - 2 WIPERS/WASHERSRS
WIPERS/WASHERS (Continued)

REAR WIPER MOTOR
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove rear wiper arm. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/REAR WIPER ARM -
REMOVAL) in this section.
(3) Open liftgate.
(4) Remove liftgate trim panel. (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
TRIM PANEL - REMOVAL).
(5) Disconnect wire connector from rear wiper
motor.
(6) Remove screws holding rear wiper motor to lift-
gate (Fig. 3).
(7) Remove wiper motor from liftgate.
INSTALLATION
(1) Position the wiper motor in the liftgate.
(2) Install the retaining screws.
(3) Connect the wire harness connector.
(4) Install the liftgate trim panel. (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
TRIM PANEL - INSTALLATION).
(5) Connect wire connector to rear wiper motor.
(6) Install the screws holding rear wiper motor to
liftgate (Fig. 3).
(7) Install the wiper motor to the liftgate (Fig. 3).
(8) Close the liftgate.
(9) Install the wiper arm. (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/REAR WIPER ARM -
INSTALLATION) in this section.
(10) Connect the battery negative cable.
REAR WIPER/WASHER
SWITCH
DESCRIPTION
On Automatic Temperature Control (ATC) vehicles
only, the rear window wiper/washer switches are
located on the center bezel with the hazard and
heated seat switches (Fig. 4). They are not service-
able separately from the hazard and heated seat
switches. If defective, the entire switch assembly
must be replaced.
On Manual Temperature Control (MTC) vehicles
only, the rear window wiper/washer switch is located
on the HVAC control head (Fig. 5) attached to the
center bezel. They are not serviceable separately
from the control head. If found faulty, the entire
MTC head must be replaced.
OPERATION
When rear wiper operation is required, the BCM
will provide ignition ON voltage to the rear wiper
motor. When the wiper switch is turned OFF, the
BCM provides circuit ground to operate the motor
until the wipe cycle is complete and the wiper arm
returns to the base of the rear window.
The rear wiper/washer switch only offers an inter-
mittent rear wiper mode. The wiper motor will cycle
every 7 seconds. The intermittent delay time is also
adjusted based upon vehicle speed. With the vehicle
traveling greater than 50 mph, the cycle changes to
every 5 seconds.
Fig. 3 REAR WINDOW WIPER MOTOR
1 - REAR WINDOW
2 - REAR WIPER MOTOR
3 - CHMSL
4 - WELL NUTS
Fig. 4 INSTRUMENT PANEL CENTER BEZEL
1 - TRIM BEZEL
2 - IN CAR TEMPERATURE SENSOR
3 - A/C REQUEST SWITCH
4 - REAR WINDOW DEFOGGER/HEATED MIRRORS SWITCH
COMBO
5 - FRONT WINDOW DEFROSTER MODE SELECTOR
RSWIPERS/WASHERS8R-11

STANDARD PROCEDURE - MEASURING
CAMSHAFT END PLAY
(1) Oil camshaft journals and install camshaft
WITHOUTrocker arms. Install rear cam caps and
tighten screws to specified torque.
(2) Using a suitable tool, move camshaft as far
rearward as it will go.
(3) Zero dial indicator (Fig. 24).
(4) Move camshaft as far forward as it will go.
(5) Record reading on dial indicator. For end play
specification, (Refer to 9 - ENGINE - SPECIFICA-
TIONS).
(6) If end play is excessive, check cylinder head
and camshaft for wear; replace as necessary.
REMOVAL
(1) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER - REMOVAL).
(2) Remove camshaft position sensor and camshaft
target magnet (Refer to 8 - ELECTRICAL/IGNITION
CONTROL/CAMSHAFT POSITION SENSOR -
REMOVAL).
(3) Remove timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT AND SPROCKETS -
REMOVAL).(4) Remove camshaft sprockets and timing belt
rear cover (Refer to 9 - ENGINE/VALVE TIMING/
TIMING BELT COVER(S) - REMOVAL).
(5) Bearing caps are identified for location.
Remove the outside bearing caps first (Fig. 25).
(6) Loosen the camshaft bearing cap attaching
fasteners in sequence shown (Fig. 26) one camshaft
at a time.
CAUTION: Camshafts are not interchangeable. The
intake cam number 6 thrust bearing face spacing is
wider.
(7) Identify the camshafts before removing from
the head. The camshafts are not interchangeable.
(8) Remove camshafts from cylinder head.
NOTE: If removing rocker arms, identify for reinstal-
lation in the original position.
CLEANING
Clean camshaft with a suitable solvent.
Fig. 23 Camshafts
1 - CAMSHAFT BEARING CAPS
2 - PLUG
3 - CAMSHAFT
4 - CYLINDER HEAD
5 - CAMSHAFT OIL SEAL
Fig. 24 Camshaft End Play - Typical
Fig. 25 Camshaft Bearing Cap Identification
RSENGINE 2.4L9-29
CAMSHAFT(S) (Continued)

OIL
STANDARD PROCEDURE
ENGINE OIL LEVEL CHECK
The best time to check engine oil level is after it
has sat overnight, or if the engine has been running,
allow the engine to be shut off for at least 5 minutes
before checking oil level.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil level
reading. Remove dipstick and observe oil level. Add
oil only when the level is at or below the ADD mark
(Fig. 86).
STANDARD PROCEDURE - ENGINE OIL AND
FILTER CHANGE
Change engine oil at mileage and time intervals
described in the Maintenance Schedule. (Refer to
LUBRICATION & MAINTENANCE/MAINTE-
NANCE SCHEDULES - DESCRIPTION)
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-
MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Remove oil fill cap.
(3) Hoist and support vehicle on safety stands.
Refer to Hoisting and Jacking Recommendations.
(Refer to LUBRICATION & MAINTENANCE/HOIST-
ING - STANDARD PROCEDURE)(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug and
gasket if damaged.
(6) Remove oil filter. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL)
(7) Install and tighten drain plug in crankcase.
(8) Install new oil filter. (Refer to 9 - ENGINE/LU-
BRICATION/OIL FILTER - INSTALLATION)
(9) Lower vehicle and fill crankcase with specified
type and amount of engine oil. (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES -
DESCRIPTION)
(10) Install oil fill cap.
(11) Start engine and inspect for leaks.
(12) Stop engine and inspect oil level.
NOTE: Care should be exercised when disposing
used engine oil after it has been drained from a
vehicle engine. Refer to the WARNING listed above.
OIL FILTER
DESCRIPTION
The engine oil filter (Fig. 87) is a high quality full-
flow, disposable type. Replace the oil filter with a
Mopartor the equivalent.
REMOVAL
(1) Raise vehicle on hoist.
(2) Position an oil collecting container under oil fil-
ter location.
CAUTION: When servicing the oil filter avoid
deforming the filter can by installing the remove/in-
stall tool band strap against the can to base lock
seam. The lock seam joining the can to the base is
reinforced by the base plate.
(3) Using a suitable filter wrench, turn oil filter
(Fig. 87) counterclockwise to remove.
INSTALLATION
(1) Clean and check filter mounting surface. The
surface must be smooth, flat and free of debris or
pieces of gasket.
(2) Lubricate new oil filter gasket with clean
engine oil.
(3) Screw oil filter (Fig. 87) on until the gasket
contacts base. Tighten to 12 N´m (105 in. lbs.).
Fig. 86 Oil Level
1 - ENGINE OIL LEVEL DIPSTICK
RSENGINE 2.4L9-53

(6) Remove connecting rod cap. Install connecting
rod bolt protectors on connecting rod bolts (Fig. 56).
(7) Remove each piston and connecting rod assem-
bly out of the cylinder bore.
NOTE: Be careful not to nick crankshaft journals.
(8) After removal, install bearing cap on the mat-
ing rod.
INSTALLATION
(1) Before installing pistons and connecting rod
assemblies into the bore, ensure that compression
ring gaps are staggered so that neither is in line with
oil ring rail gap (Fig. 57).(2) Before installing the ring compressor, ensure
the oil ring expander ends are butted and the rail
gaps located as shown in (Fig. 57).
(3) Lubricate the piston and rings with clean
engine oil. Position a ring compressor over the piston
and rings, and tighten the compressor (Fig. 58).Be
sure position of rings does not change during
this operation.
(4) Position upper bearing onto connecting rod.
Lubricate bearing with oil.
(5) Install connecting rod bolt protectors (rubber
hose or equivalent) on the connecting rod bolts (Fig.
58).
(6) The pistons are marked with a ªFº located near
the piston pin. Install piston with this mark posi-
tioned to front of engine on both cylinder banks. The
connecting rod oil squirt hole faces the major thrust
(right) side of the engine block (Fig. 59).
(7) Rotate crankshaft until the connecting rod
journal is located in the center of the cylinder bore.
Insert connecting rod and piston into cylinder bore.
Carefully guide connecting rod over the crankshaft
journal (Fig. 58).
(8) Tap the piston down in cylinder bore, using a
hammer handle. At the same time, guide connecting
rod into position on connecting rod journal.
(9) Install lower bearing shell and connecting rod
cap (Fig. 58). Install nuts on cleaned and oiled rod
bolts and tighten to 54 N´m (40 ft. lbs.) PLUS
1¤4
turn.
(10) Repeat procedure for each piston and connect-
ing rod installation.
(11) Install the cylinder heads. (Refer to 9 -
ENGINE/CYLINDER HEAD - INSTALLATION)
(12) Install the oil pan. (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION)
(13) Fill engine crankcase with proper oil to cor-
rect level.
(14) Connect negative cable to battery.
Fig. 56 Connecting Rod Protectors
1 - COVER ROD BOLTS WITH A SUITABLE COVERING WHEN
REMOVING OR INSTALLING PISTON ASSEMBLY
Fig. 57 Piston Ring End Gap Position
1 - SIDE RAIL UPPER
2 - NO. 1 RING GAP
3 - PISTON PIN
4 - SIDE RAIL LOWER
5 - NO. 2 RING GAP AND SPACER EXPANDER GAP
9 - 118 ENGINE 3.3/3.8LRS
PISTON & CONNECTING ROD (Continued)

OIL
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE OIL AND
FILTER CHANGE
Change engine oil at mileage and time intervals
described in the Maintenance Schedule. (Refer to
LUBRICATION & MAINTENANCE/MAINTE-
NANCE SCHEDULES - DESCRIPTION)
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-
MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Open hood, remove oil fill cap (Fig. 96).
(3) Hoist and support vehicle on safety stands.
Refer to Hoisting and Jacking Recommendations.
(Refer to LUBRICATION & MAINTENANCE/HOIST-
ING - STANDARD PROCEDURE)
(4) Place a suitable drain pan under crankcase
drain (Fig. 95).
(5) Remove drain plug from crankcase (Fig. 95)
and allow oil to drain into pan. Inspect drain plug
threads for stretching or other damage. Replace
drain plug and gasket if damaged.
(6) Remove oil filter. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL)
(7) Install and tighten drain plug in crankcase.(8) Install new oil filter. (Refer to 9 - ENGINE/LU-
BRICATION/OIL FILTER - INSTALLATION)
(9) Lower vehicle and fill crankcase with specified
type and amount of engine oil. (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES -
DESCRIPTION)
(10) Install oil fill cap.
(11) Start engine and inspect for leaks.
(12) Stop engine and inspect oil level.
NOTE: Care should be exercised when disposing
used engine oil after it has been drained from a
vehicle engine. Refer to the WARNING listed above.
STANDARD PROCEDURE - ENGINE OIL LEVEL
CHECK
The best time to check engine oil level is after it
has sat overnight, or if the engine has been running,
allow the engine to be shut off for at least 5 minutes
before checking oil level.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil level
reading (Fig. 96). Add only when the level is at or
below the ADD mark.
Fig. 95 Engine Oil Drain Plug and Oil Filter
1 - DRAIN PLUG
2 - OIL FILTER
RSENGINE 3.3/3.8L9 - 137

FUEL INJECTION
OPERATION
OPERATION - INJECTION SYSTEM
All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power-
train Control Module (PCM) operates the fuel injec-
tion system.
The PCM regulates:
²Ignition timing
²Air/fuel ratio
²Emission control devices
²Cooling fan
²Charging system
²Idle speed
²Vehicle speed control
Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi-
tion to the sensors, various switches also provide
inputs to the PCM.
The PCM can adapt its programming to meet
changing operating conditions.
Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat-
ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust-
ing injector pulse width. Injector pulse width is the
length of time the injector is open.
The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
RPM (speed) and manifold absolute pressure (air
density) are theprimaryinputs that determine
injector pulse width.
OPERATION - MODES OF OPERATION
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
Wide Open Throttle (WOT). There are several differ-
ent modes of operation that determine how the PCM
responds to the various input signals.
There are two different areas of operation, OPEN
LOOP and CLOSED LOOP.
During OPEN LOOP modes the PCM receives
input signals and responds according to preset PCM
programming. Inputs from the upstream and down-
stream heated oxygen sensors are not monitored dur-
ing OPEN LOOP modes, except for heated oxygensensor diagnostics (they are checked for shorted con-
ditions at all times).
During CLOSED LOOP modes the PCM monitors
the inputs from the upstream and downstream
heated oxygen sensors. The upstream heated oxygen
sensor input tells the PCM if the calculated injector
pulse width resulted in the ideal air-fuel ratio of 14.7
to one. By monitoring the exhaust oxygen content
through the upstream heated oxygen sensor, the
PCM can fine tune injector pulse width. Fine tuning
injector pulse width allows the PCM to achieve opti-
mum fuel economy combined with low emissions.
For the PCM to enter CLOSED LOOP operation,
the following must occur:
(1) Engine coolant temperature must be over 35ÉF.
²If the coolant is over 35ÉF the PCM will wait 38
seconds.
²If the coolant is over 50ÉF the PCM will wait 15
seconds.
²If the coolant is over 167ÉF the PCM will wait 3
seconds.
(2) For other temperatures the PCM will interpo-
late the correct waiting time.
(3) O2 sensor must read either greater than 0.745
volts or less than 0.29 volt.
(4) The multi-port fuel injection systems has the
following modes of operation:
²Ignition switch ON (Zero RPM)
²Engine start-up
²Engine warm-up
²Cruise
²Idle
²Acceleration
²Deceleration
²Wide Open Throttle
²Ignition switch OFF
(5) The engine start-up (crank), engine warm-up,
deceleration with fuel shutoff and wide open throttle
modes are OPEN LOOP modes. Under most operat-
ing conditions, the acceleration, deceleration (with
A/C on), idle and cruise modes,with the engine at
operating temperatureare CLOSED LOOP modes.
IGNITION SWITCH ON (ZERO RPM) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
²The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input. The
PCM determines basic fuel injector pulse width from
this input.
²The PCM determines atmospheric air pressure
from the MAP sensor input to modify injector pulse
width.
When the key is in the ON position and the engine
is not running (zero rpm), the Auto Shutdown (ASD)
and fuel pump relays de-energize after approximately
14 - 18 FUEL INJECTIONRS

²All monitored components (refer to the Emission
section for On-Board Diagnostics).
The PCM compares the upstream and downstream
heated oxygen sensor inputs to measure catalytic
convertor efficiency. If the catalyst efficiency drops
below the minimum acceptable percentage, the PCM
stores a diagnostic trouble code in memory, after 2
trips.
During certain idle conditions, the PCM may enter
a variable idle speed strategy. During variable idle
speed strategy the PCM adjusts engine speed based
on the following inputs.
²A/C status
²Battery voltage
²Battery temperature or Calculated Battery Tem-
perature
²Engine coolant temperature
²Engine run time
²Inlet/Intake air temperature
²Vehicle mileage
ACCELERATION MODE
This is a CLOSED LOOP mode. The PCM recog-
nizes an abrupt increase in Throttle Position sensor
output voltage or MAP sensor output voltage as a
demand for increased engine output and vehicle
acceleration. The PCM increases injector pulse width
in response to increased fuel demand.
²Wide Open Throttle-open loop
DECELERATION MODE
This is a CLOSED LOOP mode. During decelera-
tion the following inputs are received by the PCM:
²A/C status
²Battery voltage
²Inlet/Intake air temperature
²Engine coolant temperature
²Crankshaft position (engine speed)
²Exhaust gas oxygen content (upstream heated
oxygen sensor)
²Knock sensor
²Manifold absolute pressure
²Throttle position sensor
²IAC motor (solenoid) control changes in response
to MAP sensor feedback
The PCM may receive a closed throttle input from
the Throttle Position Sensor (TPS) when it senses an
abrupt decrease in manifold pressure. This indicates
a hard deceleration (Open Loop). In response, the
PCM may momentarily turn off the injectors. This
helps improve fuel economy, emissions and engine
braking.
WIDE-OPEN-THROTTLE MODE
This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are used by
the PCM:
²Inlet/Intake air temperature
²Engine coolant temperature
²Engine speed
²Knock sensor
²Manifold absolute pressure
²Throttle position
When the PCM senses a wide-open-throttle condi-
tion through the Throttle Position Sensor (TPS) it de-
energizes the A/C compressor clutch relay. This
disables the air conditioning system and disables
EGR (if equipped).
The PCM adjusts injector pulse width to supply a
predetermined amount of additional fuel, based on
MAP and RPM.
IGNITION SWITCH OFF MODE
When the operator turns the ignition switch to the
OFF position, the following occurs:
²All outputs are turned off, unless 02 Heater
Monitor test is being run. Refer to the Emission sec-
tion for On-Board Diagnostics.
²No inputs are monitored except for the heated
oxygen sensors. The PCM monitors the heating ele-
ments in the oxygen sensors and then shuts down.
FUEL CORRECTION or ADAPTIVE MEMORIES
DESCRIPTION
In Open Loop, the PCM changes pulse width with-
out feedback from the O2 Sensors. Once the engine
warms up to approximately 30 to 35É F, the PCM
goes into closed loopShort Term Correctionand
utilizes feedback from the O2 Sensors. Closed loop
Long Term Adaptive Memoryis maintained above
170É to 190É F unless the PCM senses wide open
throttle. At that time the PCM returns to Open Loop
operation.
OPERATION
Short Term
The first fuel correction program that begins func-
tioning is the short term fuel correction. This system
corrects fuel delivery in direct proportion to the read-
ings from the Upstream O2 Sensor.
The PCM monitors the air/fuel ratio by using the
input voltage from the O2 Sensor. When the voltage
reaches its preset high or low limit, the PCM begins
to add or remove fuel until the sensor reaches its
switch point. The short term corrections then begin.
The PCM makes a series of quick changes in the
injector pulse-width until the O2 Sensor reaches its
14 - 20 FUEL INJECTIONRS
FUEL INJECTION (Continued)

opposite preset limit or switch point. The process
then repeats itself in the opposite direction.
Short term fuel correction will keep increasing or
decreasing injector pulse-width based upon the
upstream O2 Sensor input. The maximum range of
authority for short term memory is 25% (+/-) of base
pulse-width. Short term is violated and is lost when
ignition is turned OFF.
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 has a spe-
cific 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 update
in 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.
RSFUEL INJECTION14-21
FUEL INJECTION (Continued)

INSTALLATION - 2.4L
(1) Install the crankshaft sensor.
(2) Install crankshaft sensor bolt and tighten.
(3) Connect the electrical connector (Fig. 8).
(4) Lower vehicle.
(5) Connect the negative battery cable.
ENGINE SPEED SENSOR
DESCRIPTION
The PCM receives a signal from the TCM to indi-
cate vehicle speed on automatic transmission cars.
On 4 cylinder Manual transmission cars (if equipped)
vehicle, a dedicated vehicle speed sensor is connectedto the PCM.On V-6 Manual transmission cars (if
equipped) vehicle, the ABS module provides the sig-
nal to the PCM for vehicle speed.
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. 10).
OPERATION
The fuel injectors are 12 volt electrical solenoids
(Fig. 11). 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,
Fig. 7 Timing Slots
1 - TORQUE CONVERTER DRIVE PLATE
2 - SLOTS
Fig. 8 CRANKSHAFT SENSOR 2.4L
Fig. 9 CRANKSHAFT POSITION SENSOR LOCATION
2.4L
14 - 26 FUEL INJECTIONRS
CRANKSHAFT POSITION SENSOR (Continued)