2004 CHRYSLER VOYAGER reset

knobs for the seat switch unit must be removed
before the seat switch can be removed from the side
shield.The power seat switch cannot be repaired. If one
switch is damaged or faulty, the entire power seat
switch unit must be replaced.
OPERATION
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the adjuster motor to
run in the opposite direction. No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged. See the owner's
manual in the vehicle glove box for more information
on the power seat switch functions and the seat
adjusting procedures.
DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH
(1) Remove the power seat switch, refer to the
Switch Removal and Installation procedures in this
section. (2) Using an ohmmeter, check pin #1 in the power
seat switch connector receptacle for continuity to
ground. It should be present. If OK, go to Step 3. If
not OK, repair the open ground circuit as required. (3) Using an voltmeter, check pin #5 of the wire
harness connector for the power seat switch for bat-
tery current. It should be present. If OK, go to Step
4. If not OK, repair the open voltage supply circuit as
required. (4) Using an ohmmeter, test the power seat switch
continuity as shown in the Test Table at the pins in
the switch connector receptacle (Fig. 3). If there is no
continuity at any of the switch positions, replace the
power seat switch.
DRIVER SEAT SWITCH CONTINUITY TEST TABLE
SWITCH
POSITION CONTINUITY BETWEEN
PINS
DRIVER
OFF PIN5&4 PIN5&3
PIN5&2
PIN5&10 PIN5&9
PIN5&8
PIN5&7
PIN5&6
FRONT RISER
UP PIN5&6
PIN1&9
FRONT RISER
DOWN PIN5&9
PIN1&6
CENTER
SWITCH
FORWARD PIN5&3
PIN1&10
CENTER
SWITCH
REARWARD PIN5&10
PIN3&1
REAR RISER UP PI N5&7
PIN1&8
REAR RISER
DOWN PIN5&8
PIN1&7
RECLINER UP PI N5&2
PIN4&1
RECLINER
DOWN PIN5&4
PIN2&1
Fig. 3 SEAT SWITCH PIN CALL-OUT
RS
POWER SEAT SYSTEM8Ns-11
DRIVER SEAT SWITCH (Continued)

No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged. See the owner's
manual in the vehicle glove box for more information
on the power seat switch functions and the seat
adjusting procedures.
DIAGNOSIS AND TESTING - PASSENGER SEAT
SWITCH
(1) Remove the power seat switch, refer to the
Switch Removal and Installation procedures in this
section. (2) Using an ohmmeter, check pin #1 of the power
seat switch connector for continuity to ground. It
should be present, If OK go to Ste p3,IfNOTOK
repair the open ground circuit as required. (3) Using a voltmeter, check pin #5 of the power
seat switch connector for battery voltage. If OK, go to
Step 4. If not OK, repair the open voltage supply cir-
cuit as required. (4) Using an ohmmeter, perform the Seat Switch
Continuity Test table using (Fig. 6). If there is no
continuity at any of the switch positions, replace the
power seat switch.
PASSENGER SEAT SWITCH CONTINUITY TEST TABLE
SWITCH
POSITION CONTINUITY BETWEEN
PINS
PASSENGER
OFF PIN5&4 PIN5&3
PIN5&2
PIN5&10 PIN5&9
PIN5&8
PIN5&7
PIN5&6
FORWARD PIN5&3 PIN1&10
REARWARD PI N5&10
PIN3&1
RECLINER UP PI N5&2
PIN4&1
RECLINER
DOWN PIN5&4
PIN2&1
REMOVAL
(1) Disconnect and isolate the battery negative
cable. (2) On models equipped with the eight-way power
seat, using a push pin remover or another suitable
wide flat-bladed tool, gently pry the power seat and
power recliner switch knobs off of the switch levers
(Fig. 7).
(3) Remove the screws that secure the outboard
seat cushion side shield to the seat cushion frame.
Refer to the Body section of the service manual for
the procedure. (4) Pull the outboard seat cushion side shield away
from the seat cushion frame far enough to access the
power seat switch wire harness connector. (5) Disconnect the power seat wire harness connec-
tor from the power seat switch connector receptacle. (6) Remove the screws that secure the power seat
switch to the inside of the outboard seat cushion side
shield. (7) Remove the power seat switch from the out-
board seat cushion side shield.
Fig. 6 SEAT SWITCH PIN CALL-OUT
Fig. 7 REMOVING SWITCH CONTROL KNOBS - TYPICAL
8Ns - 14 POWER SEAT SYSTEMRS
PASSENGER SEAT SWITCH (Continued)

INSTALLATION
(1) Position the power seat switch onto the out-
board seat cushion side shield. (2) Install and tighten the screws that secure the
power seat switch to the inside of the outboard seat
cushion side shield. Tighten the screws to 1.5 N´m
(14 in. lbs.). (3) Reconnect the power seat wire harness connec-
tor to the power seat switch connector receptacle. (4) Position the outboard seat cushion side shield
onto the seat cushion frame (5) Install and tighten the screws that secure the
outboard seat cushion side shield to the seat cushion
frame. Tighten the screws to 1.5 N´m (14 in. lbs.). (6) Install the switch knobs on the switch control
levers, if equipped. (7) Reconnect the battery negative cable.
DRIVER POWER SEAT TRACK
DESCRIPTION
The eight-way driver side power seat option
includes a electrically operated power seat track
located under the driver side front seat. The front
power seat track on the driver side of the vehicle also
provides the mounting location for the Memory Seat/
Mirror Module (MSMM). The power seat circuit
breakers are mounted on the rear of the driver side
power seat track, just behind the seat rear trim
panel. The lower half of the power seat track is
secured to the floor panel via four studs and nuts
that must be accessed from the underside of the vehi-
cle. Four bolts secure the bottom of the seat cushion
pan to the upper half of the power seat track unit.
Four additional bolts secure the seat back frame to
the power seat track unit. The power seat track unit includes four reversible
electric motors that are secured to the upper half of
the track unit. Each motor moves the seat adjuster
through a combination of worm-drive gearboxes and
screw-type drive units. Each of the four power seat
track motors used on models equipped with the
optional memory system incorporates a position
potentiometer integral to the motor assembly, which
electronically monitors the motor position. This
enables the memory system to function by referenc-
ing the motor positions programmed into the memory
seat/mirror module. The front and rear of the seat are operated by two
separate vertical adjustment motors. These motors
can be operated independently of each other, tilting
the entire seat assembly forward or rearward; or,
they can be operated in unison by selecting the
proper power seat switch functions, which will raise
or lower the entire seat assembly. A third motor is the horizontal adjustment motor, which moves the
seat track in the forward and rearward directions.
The forth motor is the recliner adjustment motor,
which moves the seat back in the forward and rear-
ward directions.
The power seat track unit cannot be repaired, and
is serviced only as a complete unit. If any component
in this unit is faulty or damaged, the entire power
seat track unit must be replaced.
OPERATION
When the driver side power seat switch control
knob or knobs are actuated, a battery feed and a
ground path are applied through the switch contacts
to the power seat track or recliner adjuster motor.
The selected adjuster motor operates to move the
seat track or recliner through its drive unit in the
selected direction until the switch is released, or
until the travel limit of the adjuster is reached.
When the switch is moved in the opposite direction,
the battery feed and ground path to the motor are
reversed through the switch contacts. This causes the
adjuster motor to run in the opposite direction. No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged. See the owner's manual in the vehicle glove box for
more information on the power seat switch functions
and the seat adjusting procedures.
DIAGNOSIS AND TESTING - DRIVER POWER
SEAT TRACK
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK MOUNTED AIRBAGS. BEFORE
ATTEMPTING TO DIAGNOSE OR SERVICE ANY
SEAT OR POWER SEAT SYSTEM COMPONENT
YOU MUST FIRST DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE CABLE. THEN WAIT TWO MIN-
UTES FOR THE SYSTEM CAPACITOR TO DIS-
CHARGE BEFORE FURTHER SYSTEM SERVICE.
THIS IS THE ONLY SURE WAY TO DISABLE THE
AIRBAG SYSTEM. FAILURE TO DO SO COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
Actuate the driver side power seat switch to move
all three power seat track adjusters in each direction.
The power seat track adjusters should move in each
of the selected directions. If a power seat track
adjuster fails to operate in only one direction, move
the adjuster a short distance in the opposite direction
RS POWER SEAT SYSTEM8Ns-15
PASSENGER SEAT SWITCH (Continued)

cle. Four bolts secure the bottom of the seat cushion
frame to the upper half of the power seat track unit.
Four additional bolts secure the seat back frame to
the power seat track unit.The passenger side power seat track unit includes
two reversible electric motors that are secured to the
upper half of the track unit. Each motor moves the
seat adjuster through a combination of worm-drive
gearboxes and screw-type drive units. The horizontal
adjustment motor moves the seat track in the for-
ward and rearward directions. The recliner adjust-
ment motor moves the seat back in the forward and
rearward directions. The power seat track unit cannot be repaired, and
is serviced only as a complete unit. If any component
in this unit is faulty or damaged, the entire power
seat track unit must be replaced.
OPERATION
When a passenger side power seat switch control
knob or knobs are actuated, a battery feed and a
ground path are applied through the switch contacts
to the power seat track or recliner adjuster motor.
The selected adjuster motor operates to move the
seat track or recliner through its drive unit in the
selected direction until the switch is released, or
until the travel limit of the adjuster is reached.
When the switch is moved in the opposite direction,
the battery feed and ground path to the motor are
reversed through the switch contacts. This causes the
adjuster motor to run in the opposite direction. No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged. See the owner's manual in the vehicle glove box for
more information on the power seat switch functions
and the seat adjusting procedures.
DIAGNOSIS AND TESTING - POWER SEAT
TRACK
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK MOUNTED AIRBAGS. BEFORE
ATTEMPTING TO DIAGNOSE OR SERVICE ANY
SEAT OR POWER SEAT SYSTEM COMPONENT
YOU MUST FIRST DISCONNECT AND ISOLATE THE BATTERY NEGATIVE CABLE. THEN WAIT TWO MIN-
UTES FOR THE SYSTEM CAPACITOR TO DIS-
CHARGE BEFORE FURTHER SYSTEM SERVICE.
THIS IS THE ONLY SURE WAY TO DISABLE THE
AIRBAG SYSTEM. FAILURE TO DO SO COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
Actuate the passenger side power seat switch to
move the power seat track adjuster in each direction.
The power seat track adjuster should move in each of
the selected directions. If a power seat track adjuster
fails to operate in only one direction, move the
adjuster a short distance in the opposite direction
and test again to be certain that the adjuster is not
at its travel limit. If the power seat track adjuster
still fails to operate in only one direction, refer to
Diagnosis and Testing Power Seat Switch in this
section. If the power seat track adjuster fails to oper-
ate in more than one direction, perform the following
tests. For complete circuit diagrams, refer to Wiring
Diagrams .
(1) Check the power seat circuit breaker under the
seat. If OK, go to Step 2. If not OK, replace the
faulty power seat circuit breaker. (2) Check for battery voltage at the power seat cir-
cuit breaker under the seat. If OK, go to Step 3. If
not OK, repair the open fused B(+) circuit to the fuse
in the Intelligent Power Module as required. (3) Remove the outboard seat cushion side shield
from the seat. Disconnect the seat wire harness con-
nector from the power seat switch connector recepta-
cle. Check for battery voltage at the fused B(+)
circuit cavity of the power seat wire harness connec-
tor for the power seat switch. If OK, go to Step 4. If
not OK, repair the open fused B(+) circuit to the
power seat circuit breaker under the seat as
required. (4) Check for continuity between the ground cir-
cuit cavity of the power seat wire harness connector
for the power seat switch and a good ground. There
should be continuity. If OK, go to Step 5. If not OK,
repair the open ground circuit to ground as required. (5) Test the power seat switch. Refer to Diagnosis
and Testing Power Seat Switch in this section. If
the switch tests OK, test the circuits of the power
seat wire harness between the inoperative power seat
track adjuster motor and the power seat switch for
shorts or opens. If the circuits check OK, replace the
faulty power seat track unit. If the circuits are not
OK, repair the power seat wire harness as required.
RS POWER SEAT SYSTEM8Ns-17
PASSENGER POWER SEAT TRACK (Continued)

8W-97 POWER DISTRIBUTION SYSTEM
TABLE OF CONTENTS
page page
POWER DISTRIBUTION SYSTEM
DESCRIPTION..........................1
OPERATION............................1
SPECIAL TOOLS
POWER DISTRIBUTION SYSTEMS.........1
INTEGRATED POWER MODULE
DESCRIPTION..........................2
OPERATION............................2
REMOVAL.............................2
INSTALLATION..........................3IOD FUSE
DESCRIPTION..........................3
OPERATION............................3
POWER OUTLET
DESCRIPTION..........................4
OPERATION............................4
DIAGNOSIS AND TESTING
DIAGNOSIS & TESTING - POWER OUTLET . . 4
REMOVAL.............................5
INSTALLATION..........................5
POWER DISTRIBUTION
SYSTEM
DESCRIPTION
This group covers the various standard and
optional power distribution components used on this
model. The power distribution system for this vehicle
consists of the following components:
²Integrated Power Module (IPM)
²Front Control Module (FCM)
²Power Outlets
Refer to Wiring Diagrams for complete circuit sche-
matics.
The power distribution system also incorporates
various types of circuit control and protection fea-
tures, including:
²Automatic resetting circuit breakers
²Blade-type fuses
²Bus bars
²Cartridge fuses
²Circuit splice blocks
²Flashers
²Fusible links
²Relays
Following are general descriptions of the major
components in the power distribution system. See the
owner's manual in the vehicle glove box for more
information on the features and use of all of the
power distribution system components.
OPERATION
The power distribution system for this vehicle is
designed to provide safe, reliable, and centralized dis-
tribution points for the electrical current required to
operate all of the many standard and optional facto-
ry-installed electrical and electronic powertrain,
chassis, safety, security, comfort and convenience sys-
tems. At the same time, the power distribution sys-
tem was designed to provide ready access to these
electrical distribution points for the vehicle techni-
cian to use when conducting diagnosis and repair of
faulty circuits. The power distribution system can
also prove useful for the sourcing of additional elec-
trical circuits that may be required to provide the
electrical current needed to operate many accessories
that the vehicle owner may choose to have installed
in the aftermarket.
SPECIAL TOOLS
POWER DISTRIBUTION SYSTEMS
Terminal Pick Kit 6680
RS8W-97 POWER DISTRIBUTION SYSTEM8W-97-1

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)