reset CHRYSLER VOYAGER 2001 Service Manual
Page 2007 of 4284
CONDITION POSSIBLE CAUSES CORRECTION
Check for foreign matter preventing the
operation of latch assembly
Troubleshoot using body diagnostic manual
Replace latch assembly, if necessary
Failure of inside/outside handle
assemblyGo to that9POSSIBLE CAUSE9and review
9CORRECTIONS9
Binding or sticking of components Establish location of binding and replace
necessary components
Door continues to cinch
closed during power modeFailure of latch assembly Check wire connections and for blown fuse
Check for foreign matter preventing the
operation of latch assembly
Troubleshoot using body diagnostic manual
Replace latch assembly, if necessary
Failure of sliding door control or
body control moduleDisconnect then reconnect battery to reset
module, function door, if no function exists
check for loose wire connections, see Body
Diagnostic Manual for detailed procedures
Wiring problems (system or vehicle) Troubleshoot using electrical schematics.
Refer to wiring diagrams
Door continues to open
during power mode
(runaway motor)Failure of sliding door control or
body control moduleDisconnect then reconnect battery to reset
module, function door, if no function exists
check for loose wire connections, see Body
Diagnostic Manual for detailed procedures
Failure of hold open latch assembly Check wire/cable connections
Replace hold open latch, if necessary
Failure of drive assembly Remove lower drive unit and check for no
drive condition
Wiring problems (system or vehicle) Troubleshoot using electrical schematics.
Refer to wiring diagrams
Door opens very slowly Failure of door motor assembly Check wire/cable connections
Replace motor assembly, if necessary
Binding or sticking of components Establish location of binding and replace
necessary components
Squeaks, Noises and rattles Foreign material in door
compartmentRemove foreign material
Loose components Check and tighten loose components
Poor door track lubrication Lubricate the front portions of the side door
tracks with9Door EaseT9or equivalent
RSPOWER SLIDING DOOR SYSTEM8N-27
POWER SLIDING DOOR SYSTEM (Continued)
Page 2030 of 4284
A eight-way power seat is standard on highline
models and optional on others. This option includes a
six-way adjustable seat cushion track and a two-way
power seat back.
The eight-way power seat is also available with the
heated seat and memory seat system that automati-
cally positions the power seat for two different driv-
ers. Refer toHeated Seat Systemfor more
information on the heated seat option. Refer toMem-
ory Systemin the Memory System section of this
group for more information on the memory system.
The power seat system includes the following com-
ponents:
²Power seat recliner
²Power seat switch
²Power seat track.
The power seat system with memory and heated
seat options includes the following components:
²Power seat recliner
²Power seat switch
²Power seat track.
²Memory Heated Seat Module (MHSM)
²Memory set switch
²Heated seat switch
²Electronic Vehicle Information Center (EVIC)
²Programmable Communications Interface (PCI)
data bus network
Refer to Wiring Diagrams for complete circuit dia-
grams. Following are general descriptions and opera-
tions for the major components in the power seat
system and memory seat system.
DESCRIPTION - MEMORY SEAT SYSTEM
An electronic memory and heated seat system is
available on some models. The memory system is
able to store and recall the driver side power seat
positions (including the power recliner position), and
both outside power mirror positions for two drivers.
For vehicles with a radio and heated / memory seat
system connected to the Programmable Communica-
tions Interface (PCI) data bus network, the memory
system is also able to store and recall radio station
presets for two drivers. The memory system also will
store and recall the last station listened to for each
driver, even if it is not one of the preset stations.
The memory system will automatically return to
all of these settings when the corresponding num-
bered and button of the memory switch on the driver
side seat side shield is depressed, or when the doors
are unlocked using the Remote Keyless Entry (RKE)
transmitter. A customer programmable feature of the
memory system allows the RKE recall of memory fea-
tures to be disabled in cases where there are more
than two drivers of the vehicle.
A Memory Heated Seat Module (MHSM) is used on
some models to control and integrate the many elec-tronic functions and features included in the memory
/ heated seat system.
The memory system includes the following compo-
nents:
²Heated seat switch
²Memory heated seat module (MHSM)
²Memory switch
²Position potentiometers on both outside power
mirrors
²Position potentiometers on the driver side power
seat track and power seat recliner motors.
²Radio receiver (if PCI data bus capable).
Certain functions and features of the memory system
rely upon resources shared with other electronic mod-
ules in the vehicle over the Programmable Communica-
tions Interface (PCI) J1850 data bus network. The PCI
data bus network allows the sharing of sensor informa-
tion. This helps to reduce wire harness complexity,
internal controller hardware, and component sensor cur-
rent loads. At the same time, this system provides
increased reliability, enhanced diagnostics, and allows
the addition of many new feature capabilities. For diag-
nosis of these electronic modules or of the PCI data bus
network, the use of a DRBtscan tool and the proper
Diagnostic Procedures manual are recommended.
The other electronic modules that may affect mem-
ory system operation are as follows:
²Body Control Module (BCM)- Refer toBody
Control Modulein Electronic Control Modules for
more information.
²
Electronic Vehicle Information Center (EVIC)
- Refer toElectronic Vehicle Information Center
in Overhead Console Systems for more information.
²Powertrain Control Module (PCM)- Refer to
Powertrain Control Modulein Electronic Control
Modules for more information.
²Radio Receiver- Refer toRadio Receiverin
Audio Systems for more information.
Refer toHeated Seat Systemfor more informa-
tion on the heated seat system. Refer toRemote
Keyless Entry Systemin Power Lock Systems for
more information on the RKE system. Refer to
Power Mirrorin Power Mirrors for more informa-
tion on the mirror position potentiometers. Refer to
Power Seat TrackandPower Seat Reclinerin
the Power Seat System section of this group for more
information on the driver side power seat position
potentiometers.
Refer toPower Seatin the Contents of Wiring
Diagrams for complete circuit diagrams. Following
are general descriptions of the remaining major com-
ponents in the factory-installed memory system.
OPERATION - POWER SEAT SYSTEM
The power seat system allows the driver and/or
front passenger seating positions to be adjusted elec-
8N - 50 POWER SEATSRS
POWER SEATS (Continued)
Page 2031 of 4284
trically and independently using the separate power
seat switches found on the outboard seat cushion
side shield of each front seat. See the owner's manual
in the vehicle glove box for more information on the
features, use and operation of the power seat system.
OPERATION - MEMORY SYSTEM
The Memory Seat/Mirror Module (MSMM) will
drive a maximum of 2 motors at a time in a given
direction. If conflicting directions are requested, the
priority for response will be as follows:
²Seat Track Rearward
²Seat Front Down
²Seat Rear Down
²Recliner Rearward
²Seat Track Forward
²Seat Front Up
²Seat Rear Up
²Recliner Forward
The inputs from these switches to the MSMM is a
current limited battery source fed by the MSMM.
This protects the MSMM printed circuit board traces
from acting as fuses. All of these switch contact
inputs to the MSMM are normally closed to ground,
except when actuated.
Soft stops are incorporated to prevent the motor
from being driven into a stall. Should the seat have
restricted travel, refer to Resetting Soft Stops in this
section.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the memory system. For diagnosis of the MSM, the
PCI data bus, or the other electronic modules on the
PCI data bus that provide inputs and outputs for the
memory system, the use of a DRBtscan tool and the
proper Diagnostic Procedures manual are recom-
mended.
ELECTRONIC VEHICLE INFORMATION CENTER
The Electronic Vehicle Information Center (EVIC)
serves as the user interface for the memory system.
It displays memory system status messages and pro-
vides the user with the means for enabling and dis-
abling the many customer programmable features
available on the vehicle, including those for the mem-
ory system.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the EVIC. Refer toElectronic Vehicle Informa-
tion Centerin Overhead Console Systems for more
information on the EVIC.
DIAGNOSIS AND TESTING - POWER SEAT
SYSTEM
Following are tests that will help to diagnose the
hard wired components and circuits of the power seatsystem. However, if the vehicle is also equipped with
the optional memory system, these tests may not
prove conclusive in the diagnosis of the driver side
power seat. In order to obtain conclusive testing of
the driver side power seat with the memory system
option, the Programmable Communications Interface
(PCI) data bus network and all of the electronic mod-
ules that provide inputs to, or receive outputs from
the memory system components must be checked.
The most reliable, efficient, and accurate means to
diagnose the driver side power seat with the memory
system option requires the use of a DRBtscan tool
and the proper Diagnostic Procedures manual. The
DRBtscan tool can provide confirmation that the
PCI data bus is functional, that all of the electronic
modules are sending and receiving the proper mes-
sages on the PCI data bus, and that the memory sys-
tem is receiving the proper hard wired inputs and
relaying the proper hard wired outputs to perform its
driver side power seat functions.
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK MOUNTED AIRBAGS (Fig. 1). 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.
Before any testing of the power seat system is
attempted, the battery should be fully-charged and
all of the power seat system wire harness connections
and pins cleaned and tightened to ensure proper cir-
cuit continuity and ground paths. For complete cir-
cuit diagrams, refer toPower Seatin Wiring
Diagrams.
With the dome lamp on, apply the power seat
switch in the direction of the failure. If the dome
lamp dims, the seat may be jamming. Check under
and behind the seat for binding or obstructions. If
the dome lamp does not dim, proceed with testing of
the individual components and circuits.
DIAGNOSIS AND TESTING - MEMORY SYSTEM
CHECK AND RESET SOFT STOPS
To check and reset the power memory seat soft
stops, use the power seat control switches to move
the seat in one direction to the end of travel, allow a
couple of seconds before re-energizing the seat in the
same direction until it stops and for three additional
seconds after it stops. (The amount the seat moved
RSPOWER SEATS8N-51
POWER SEATS (Continued)
Page 2032 of 4284
upon the second energizing is the amount the soft
stops have been reprogrammed.
Repeat this procedure for each direction of seat
movement (One at a time).
NOTE: Checking and resetting of the power mem-
ory seat soft stops will not affect the customer's
programmed positions.
DIAGNOSIS AND TESTING MEMORY SYSTEM
In order to obtain conclusive testing of the memory
system, the Programmable Communications Interface
(PCI) data bus network and all of the electronic mod-
ules that provide inputs to, or receive outputs from
the memory system components must be checked.
The most reliable, efficient, and accurate means to
diagnose the memory system requires the use of a
DRB IIItscan tool and the proper Diagnostic Proce-
dures manual. The DRB IIItscan tool can provide
confirmation that the PCI data bus is functional, that
all of the electronic modules are sending and receiv-
ing the proper messages on the PCI data bus, and
that the memory system is receiving the proper hard
wired inputs and relaying the proper hard wired out-
puts to perform its functions.
Following are diagnostic routines that are built
into the module which can be performed without the
use of a diagnostic scan tool. Refer to Wiring Dia-
grams for complete circuit schematic or connector
pin-out information.
DIAGNOSTIC MODE 1
Diagnostic Mode 1 clears soft limits and sets mem-
ory selector switches (1 and 2) to predetermined val-
ues.
ACTIVATION-Press and hold the S and 1 buttons
for 5 seconds to enter diagnostic mode 1. This mode
is exited at the completion of the mode 1 tasks or
upon grounding the DATA G87 circuit input to the
module.
Mode 1 will:
²Clear all soft limits to their default hard limit
values
²Load memory 1 with default settings corre-
sponding to horizontal rearward, front down, rear
down, and recliner rearward positions
²Load memory 2 with default settings corre-
sponding to horizontal forward, front up, rear up,
and recliner forward positions
DIAGNOSTIC MODE 2
Diagnostic mode 2 provides a way to determine if
the seat/mirror motors and position sensors are con-
nected properly.
ACTIVATION-Press and hold the S and 2 buttons
for 5 seconds to enter diagnostic mode 2. This modeis exited after 5 seconds of switch inactivity or upon
grounding the DATA G87 circuit input by moving the
transmission out of the PARK position.
Mode 2 will:
²Place the seat and mirror motors at their mid-
point
²When a single axis of seat or mirror motion is
requested by pressing a switch, the corresponding
motor is energized. This tests switch input and motor
output
DRIVER SEAT SWITCH
DESCRIPTION
Vehicles equipped with power seats utilize a eight-
way power seat switch. This eight-way power seat
switch features two knobs ganged together on the
outboard seat cushion side shield (Fig. 2).
The switch is secured to the back of the seat cush-
ion side shield with two screws. However, the control
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
The power seat tracks can be adjusted in eight dif-
ferent ways using the power seat switches. See the
owner's manual in the vehicle glove box for more
information on the power seat switch functions and
the seat adjusting procedures.
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
Fig. 2 Power Seat Switch - Typical
8N - 52 POWER SEATSRS
POWER SEATS (Continued)
Page 2033 of 4284
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.
DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH
(1) Remove switch, refer to Switch Removal and
Installation in this section.
(2) Using an ohmmeter, perform the Seat Switch
Continuity Test table, using the seat switch connec-
tor (Fig. 3). If there is no continuity at any of the
switch positions, replace switch.
DRIVER SEAT SWITCH CONTINUITY TEST
SWITCH
POSITIONCONTINUITY BETWEEN
PINS
DRIVER
OFF PIN5&4
PIN5&3
PIN5&2
PIN5&10
PIN5&9
PIN5&8
PIN5&7
PIN5&6
FRONT RISER
UPPIN5&6
PIN1&9
FRONT RISER
DOWNPIN5&9
PIN1&6
CENTER
SWITCH
FORWARDPIN5&3
PIN1&10
CENTER
SWITCH
REARWARDPIN5&10
PIN3&1
REAR RISER UP PIN5&7
PIN1&8
REAR RISER
DOWNPIN5&8
PIN1&7
RECLINER UP PIN5&2
PIN4&1
RECLINER
DOWNPIN5&4
PIN2&1
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) On models with the eight-way power seat sys-
tem only, using a push pin remover or another suit-
able wide flat-bladed tool, gently pry the power seat
and power recliner switch knobs off of the switch
stems (Fig. 4).
(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.
Fig. 3 Seat Switch Pin Call-Out
Fig. 4 REMOVING SWITCH CONTROL KNOBS
RSPOWER SEATS8N-53
DRIVER SEAT SWITCH (Continued)
Page 2035 of 4284
PASSENGER SEAT SWITCH
DESCRIPTION
Vehicles equipped with power seats utilize a eight-
way power seat switch. This eight-way power seat
switch features two knobs ganged together on the
outboard seat cushion side shield (Fig. 5).
The switch is secured to the back of the seat cush-
ion side shield with two screws. However, the control
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
The power seat tracks can be adjusted in eight dif-
ferent ways using the power seat switches. See the
owner's manual in the vehicle glove box for more
information on the power seat switch functions and
the seat adjusting procedures.
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.
DIAGNOSIS AND TESTING - PASSENGER SEAT
SWITCH
(1) Remove switch, refer to Switch Removal and
Installation in this section.
(2) Using an ohmmeter, perform the Seat Switch
Continuity Test table and (Fig. 6). If there is no con-
tinuity at any of the switch positions, replace switch.
PASSENGER SEAT SWITCH CONTINUITY
TEST
SWITCH
POSITIONCONTINUITY BETWEEN
PINS
PASSENGER
OFF PIN5&4
PIN5&3
PIN5&2
PIN5&10
PIN5&9
PIN5&8
PIN5&7
PIN5&6
FRONT RISER
UPPIN5&9
PIN1&6
FRONT RISER
DOWNPIN5&6
PIN1&9
CENTER
SWITCH
FORWARDPIN5&3
PIN1&10
CENTER
SWITCH
REARWARDPIN5&10
PIN3&1
REAR RISER UP PIN5&8
PIN1&7
REAR RISER
DOWNPIN5&7
PIN1&8
RECLINER UP PIN5&2
PIN4&1
RECLINER
DOWNPIN5&4
PIN2&1
Fig. 5 Power Seat Switch - Typical
RSPOWER SEATS8N-55
Page 2094 of 4284
SPECIAL TOOLS
SPECIAL TOOLS - WIRING/TERMINALCONNECTOR - AUGAT
REMOVAL
(1) Disconnect battery.
(2) Disconnect the connector from its mating half/
component.
(3) Push down on the yellow connector locking tab
to release the terminals (Fig. 8).
(4) Using special tool 6932, push the terminal to
remove it from the connector (Fig. 9).
(5) Repair or replace the terminal as necessary.
INSTALLATION
(1) Reset the terminal locking tang.
PROBING TOOL PACKAGE 6807
TERMINAL PICK 6680
TERMINAL REMOVING TOOL 6932
TERMINAL REMOVING TOOL 6934
Fig. 8 AUGAT CONNECTOR REPAIR
1 - LOCKING TAB
2 - CONNECTOR
Fig. 9 USING SPECIAL TOOL 6932
1 - SPECIAL TOOL 6932
2 - CONNECTOR
8Wa - 01 - 8 8W-01 WIRING DIAGRAM INFORMATIONRG
WIRING DIAGRAM INFORMATION (Continued)
Page 2095 of 4284
(2) Insert the removed wire in the same cavity on
the repair connector.
(3) Repeat steps for each wire in the connector,
being sure that all wires are inserted into the proper
cavities. For additional connector pin-out identifica-
tion, refer to the wiring diagrams.
(4) When the connector is re-assembled, the lock-
ing tab must be placed in the locked position to pre-
vent terminal push out.
(5) Connect connector to its mating half/compo-
nent.
(6) Connect battery and test all affected systems.
CONNECTOR - MOLEX
REMOVAL
(1) Disconnect battery.
(2) Disconnect the connector from its mating half/
component.
(3) Insert special tool 6742 into the terminal end of
the connector (Fig. 10).
(4) Using special tool 6742, release the locking fin-
gers on the terminal (Fig. 11).
(5) Pull on the wire to remove it from the connec-
tor.
(6) Repair or replace the terminal as necessary.
INSTALLATION
(1) Reset the terminal locking tang.
(2) Insert the removed wire in the same cavity on
the repair connector.
(3) Repeat steps for each wire in the connector,
being sure that all wires are inserted into the proper
cavities. For additional connector pin-out identifica-
tion, refer to the wiring diagrams.(4) Connect connector to its mating half/compo-
nent.
(5) Connect battery and test all affected systems.
CONNECTOR - THOMAS AND
BETTS
REMOVAL
(1) Disconnect battery.
(2) Disconnect the connector from its mating half/
component.
(3) Push in the two lock tabs on the side of the
connector (Fig. 12).
Fig. 10 MOLEX CONNECTOR REPAIR
1 - CONNECTOR
2 - SPECIAL TOOL 6742
Fig. 11 USING SPECIAL TOOL 6742
1 - CONNECTOR
2 - SPECIAL TOOL 6742
Fig. 12 THOMAS AND BETTS CONNECTOR LOCK
RELEASE TABS
1 - LOCK TABS
RG8W-01 WIRING DIAGRAM INFORMATION8Wa-01-9
CONNECTOR - AUGAT (Continued)
Page 2096 of 4284
(4) Insert the probe end of special tool 6934 into
the back of the connector cavity (Fig. 13).
(5) Grasp the wire and tool 6934, then slowly
remove the wire and terminal from the connector.
(6) Repair or replace the terminal as necessary.
INSTALLATION
(1) Reset the terminal locking tang.
(2) Insert the removed wire in the same cavity on
the repair connector.
(3) Repeat steps for each wire in the connector,
being sure that all wires are fully seated into the
proper cavities. For additional connector pin-out
identification, refer to the wiring diagrams.
(4) Push in the single lock tab on the side of the
connector (Fig. 14).
(5) Connect connector to its mating half/compo-
nent.
(6) Connect battery and test all affected systems.
DIODE
REMOVAL
(1) Disconnect the battery.
(2) Locate the diode in the harness, and remove
the protective covering.
(3) Remove the diode from the harness, pay atten-
tion to the current flow direction (Fig. 15).
INSTALLATION
(1) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
(2) Install the new diode in the harness, making
sure current flow is correct. If necessary, refer to the
appropriate wiring diagram for current flow (Fig. 15).
(3) Solder the connection together using rosin core
type solder only.Do not use acid core solder.
(4) Tape the diode to the harness using electrical
tape. Make sure the diode is completely sealed from
the elements.
(5) Re-connect the battery and test affected sys-
tems.
Fig. 13 REMOVING WIRE TERMINAL
1 - SPECIAL TOOL 6934
Fig. 14 SINGLE LOCK TAB
1 - SINGLE LOCK TAB
Fig. 15 DIODE IDENTIFICATION
1 - CURRENT FLOW
2 - BAND AROUND DIODE INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN THE DIAGRAMS
8Wa - 01 - 10 8W-01 WIRING DIAGRAM INFORMATIONRG
CONNECTOR - THOMAS AND BETTS (Continued)
Page 2889 of 4284
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 oxygen
sensor 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 35É the PCM will wait 44
seconds.
²If the coolant is over 50ÉF the PCM will wait 38
seconds.
²If the coolant is over 167ÉF the PCM will wait
11 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 0.1 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
1 second. Therefore, battery voltage is not supplied to
the fuel pump, ignition coil, fuel injectors and heated
oxygen sensors.
ENGINE START-UP MODE
This is an OPEN LOOP mode. If the vehicle is in
park or neutral (automatic transaxles) or the clutch
pedal is depressed (manual transaxles) the ignition
switch energizes the starter relay. The following
actions occur when the starter motor is engaged.
²If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the Auto Shutdown (ASD) relay and fuel pump relay.
If the PCM does not receive both signals within
approximately one second, it will not energize the
ASD relay and fuel pump relay. The ASD and fuel
pump relays supply battery voltage to the fuel pump,
fuel injectors, ignition coil and heated oxygen sen-
sors.
²The PCM energizes the injectors (on the 69É
degree falling edge) for a calculated pulse width until
it determines crankshaft position from the camshaft
position sensor and crankshaft position sensor sig-
nals. The PCM determines crankshaft position within
1 engine revolution.
²After determining crankshaft position, the PCM
begins energizing the injectors in sequence. It adjusts
injector pulse width and controls injector synchroni-
zation by turning the individual ground paths to the
injectors On and Off.
²When the engine idles within664 RPM of its
target RPM, the PCM compares current MAP sensor
value with the atmospheric pressure value received
during the Ignition Switch On (zero RPM) mode.
Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:
²Battery voltage
²Engine coolant temperature
²Engine RPM
²Inlet/Intake air temperature (IAT)
²MAP
²Throttle position
RSFUEL INJECTION14-17
FUEL INJECTION (Continued)