relay CHRYSLER CARAVAN 2003 Owner's Guide
[x] Cancel search | Manufacturer: CHRYSLER, Model Year: 2003, Model line: CARAVAN, Model: CHRYSLER CARAVAN 2003Pages: 2177, PDF Size: 59.81 MB
Page 396 of 2177
IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM..........1
OPERATION - IGNITION SYSTEM...........1
SPECIFICATIONS
TORQUE.............................2
SPARK PLUG CABLE RESISTANCE........2
SPARK PLUG.........................2
FIRING ORDER........................3
AUTO SHUT DOWN RELAY
DESCRIPTION..........................3
OPERATION............................3
CAMSHAFT POSITION SENSOR
DESCRIPTION..........................3
OPERATION............................3
REMOVAL
REMOVAL - 2.4L.......................4
REMOVAL - 3.3/3.8L....................5
INSTALLATION
INSTALLATION - 2.4L...................5
INSTALLATION - 3.3/3.8L.................6
IGNITION COIL
DESCRIPTION..........................6
OPERATION............................6
REMOVAL
REMOVAL - 2.4L.......................7REMOVAL - 3.3/3.8L....................7
INSTALLATION
INSTALLATION - 2.4L...................7
INSTALLATION - 3.3/3.8L.................7
KNOCK SENSOR
DESCRIPTION..........................8
OPERATION............................8
REMOVAL
REMOVAL - 2.4L.......................8
REMOVAL - 3.8L.......................8
INSTALLATION
INSTALLATION - 2.4L...................8
INSTALLATION - 3.8L...................9
SPARK PLUG
DESCRIPTION
DESCRIPTION - STANDARD 4 CYLINDER . . . 9
DESCRIPTION - PLATINUM PLUGS........9
REMOVAL.............................10
INSTALLATION.........................10
SPARK PLUG CABLE
DESCRIPTION.........................10
REMOVAL - 2.0/2.4L.....................10
INSTALLATION - 2.0/2.4L.................10
IGNITION CONTROL
DESCRIPTION - IGNITION SYSTEM
NOTE: All engines use a fixed ignition timing sys-
tem. Basic ignition timing is not adjustable. All
spark advance is determined by the Powertrain
Control Module (PCM).
The distributorless ignition system used on these
engines is referred to as the Direct Ignition System
(DIS). The system's three main components are the
coils, crankshaft position sensor, and camshaft posi-
tion sensor. If equipped with the coil on plug ignition
system it utilizes an ignition coil for every cylinder, it
is mounted directly over the each spark plug.
OPERATION - IGNITION SYSTEM
The crankshaft position sensor and camshaft posi-
tion sensor are hall effect devices. The camshaft posi-
tion sensor and crankshaft position sensor generate
pulses that are inputs to the PCM. The PCM deter-
mines engine position from these sensors. The PCM
calculates injector sequence and ignition timing from
crankshaft & camshaft position. For a description of
both sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor.
RSIGNITION CONTROL8I-1
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Page 398 of 2177
FIRING ORDER
AUTO SHUT DOWN RELAY
DESCRIPTION
The relay is located in the Power Distribution Cen-
ter (PDC). For the location of the relay within the
PDC, refer to the PDC cover for location. Check elec-
trical terminals for corrosion and repair as necessary
OPERATION
The ASD sense circuit (SBEC vehicles) or the
engine switched battery (NGC vehicles) informs the
PCM when the ASD relay energizes. A 12 volt signal
at this input indicates to the PCM that the ASD has
been activated. This input is also used to power cer-
tain drivers on NGC vehicles.
When energized, the ASD relay on SBEC vehicles
supplies battery voltage to the fuel injectors, ignition
coils and the heating element in each oxygen sensor.
When energized, the ASD relay on NGC vehicles
provides power to operate the injectors, ignition coil,
generator field, O2 sensor heaters (both upstream
and downstream), evaporative purge solenoid, EGR
solenoid (if equipped) wastegate solenoid (if
equipped), and NVLD solenoid (if equipped).
For both SBEC and NGC vehicles, the ASD relay
also provides a sense circuit to the PCM for diagnos-
tic purposes. If the PCM does not receive 12 volts
from this input after grounding the control side of
the ASD relay, it sets a Diagnostic Trouble Code
(DTC). The PCM energizes the ASD any time there is
an engine speed that exceeds a predetermined value
(typically about 50 rpm). The ASD relay can also be
energized after the engine has been turned off to per-
form an O2 sensor heater test, if vehicle is equipped
with OBD II diagnostics.
As mentioned earlier, the PCM energizes the ASD
relay during an O2 sensor heater test. This test is
performed only after the engine has been shut off for
SBEC vehicles. On NGC vehicles it checks the O2
heater upon vehicle start. The PCM still operates
internally to perform several checks, including moni-
toring the O2 sensor heaters.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
The camshaft position sensor for the 3.3/3.8L is
mounted in the front of the timing case cover (Fig. 6)
and the camshaft position sensor for the 2.4L is
mounted on the end of the cylinder head (Fig. 3).
OPERATION
The camshaft position sensor provides cylinder
identification to the Powertrain Control Module
(PCM) (Fig. 1). The sensor generates pulses as
groups of notches on the camshaft sprocket pass
underneath it (Fig. 2). The PCM keeps track of
crankshaft rotation and identifies each cylinder by
the pulses generated by the notches on the camshaft
sprocket. Four crankshaft pulses follow each group of
camshaft pulses.
FIRING ORDER 2.4L
Firing Order 1-2-3-4-5-6 3.3/3.8L
1 - Electrical Connector
RSIGNITION CONTROL8I-3
IGNITION CONTROL (Continued)
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Page 401 of 2177
(1) Install target magnet in end of camshaft.
Tighten mounting screw to 3 N´m (30 in. lbs.) torque.
Over torqueing could cause cracks in magnet. If mag-
net cracks replace it.
(2) Install camshaft position sensor. Tighten sensor
mounting screws to 12.9 N´m (115 in. lbs.) torque.
(3) Carefully attach electrical connector to cam-
shaft position sensor.
(4) Connect the negative battery cable.
INSTALLATION - 3.3/3.8L
If the removed sensor is reinstalled, clean off
the old spacer on the sensor face. A NEW
SPACER must be attached to the face before
installation.Inspect O-ring for damage, replace if
necessary. If the sensor is being replaced, confirm
that the paper spacer is attached to the face and
O-ring is positioned in groove of the new sensor (Fig.
8).
(1) Apply a couple drops of clean engine oil to the
O-ring prior to installation.
(2) Install sensor in the chain case cover and
rotate into position.
(3) Push sensor down until contact is made with
the camshaft gear. While holding the sensor in this
position, install and tighten the retaining bolt 14
N´m (125 in. lbs.) torque.
(4) Connect camshaft position sensor electrical
connector to harness connector.
(5) Install the air box cover and inlet hose (Fig. 5).
(6) Connect the negative battery cable.
IGNITION COIL
DESCRIPTION
The ignition coil assembly consists of 2 or 3 inde-
pendent coils molded together (Fig. 9) or (Fig. 10).
The coil assembly for the 3.3/3.8L is mounted on the
intake manifold. The coil assembly for the 2.4L is
mounted on the cylinder head cover. Spark plug
cables route to each cylinder from the coil.
OPERATION
The coil fires two spark plugs every power stroke.
One plug is the cylinder under compression, the
other cylinder fires on the exhaust stroke. The Pow-
ertrain Control Module (PCM) determines which of
the coils to charge and fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the magnetic energy in
the coil transfers to the secondary causing the spark.
The PCM will de-energize the ASD relay if it does
not receive the crankshaft position sensor and cam-
shaft position sensor inputs. Refer to Auto Shutdown
(ASD) RelayÐPCM Output, in this section for relay
operation.
Fig. 8 Camshaft Position Sensor and Spacer
1 - ELECTRICAL CONNECTOR
2 - O-RING
3 - PAPER SPACER
Fig. 9 IGNITION COIL - 2.4L
8I - 6 IGNITION CONTROLRS
CAMSHAFT POSITION SENSOR (Continued)
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WARNING
WARNING: EYE PROTECTION SHOULD BE USED
WHEN SERVICING GLASS COMPONENTS. PER-
SONAL INJURY CAN RESULT.
CAUTION: Do not touch the glass of halogen bulbs
with fingers or other possibly oily surface, reduced
bulb life will result. Do not use bulbs other than
those indicated in the Bulb Application table. Dam-
age to lamp and/or Daytime Running Lamp Module
can result. Do not use fuses, circuit breakers or
relays having greater amperage value than indi-
cated on the fuse panel or in the Owners Manual.
CAUTION: Do not use bulbs other than those listed
in the Bulb Application Table. Damage to lamp can
result. Do not touch halogen bulbs with fingers or
other oily surfaces. Bulb life will be reduced.
SPECIFICATIONS
EXTERIOR LAMPS
BULB APPLICATION TABLE
LAMP BULB
BACK-UP 3057
CHMSL 921
FRONT SIDE MARKER/PARK/
TURN3157A
FRONT FOG 9040
HEADLAMP 9007
LICENSE 168
TAIL, STOP 3057
TURN SIGNAL 3057
BULB APPLICATION TABLE - EXPORT
LAMP BULB
HEADLAMP LOW/HIGH BEAM H7
FRONT FOG H3
FRONT POSITION W5W
FRONT TURN SIGNAL PY21W
SIDE REPEATER T4W
LICENSE PLATE W5W/168
REAR TAIL AND STOP P21/5W
REAR TURN SIGNAL PY21W
BACK-UP P21W
REAR FOG P21W
CHMSL W16W/921
BRAKE LAMP SWITCH
DESCRIPTION
The brake lamp switch is located under the instru-
ment panel, at the brake pedal arm (Fig. 3). It has
three internal switches controlling various functions
of the vehicle. It's main function is to control opera-
tion of the vehicle's brake lamps. Other functions
include speed control deactivation, brake sense for
the antilock brake system and brake sense for the
brake transmission shift interlock.
CAUTION: The switch can only be adjusted once.
That is during initial installation of the switch. If the
switch is not adjusted properly or has been
removed for some service, a new switch must be
installed and adjusted.
OPERATION
When the brake pedal is pressed, the plunger on
the outside of the brake lamp switch extends out-
ward. This action opens or closes the contacts of the
three switches inside the brake lamp switch.
With the brake pedal pressed down (plunger
extended), the switch for terminals 1 and 2 is closed
completing the circuit. The switch for terminals 3
and 4 is open and so is the switch for terminals 5
and 6.
When the brake pedal is released (plunger pushed
in), the three switches assume the opposite positions.
The switch for terminals 1 and 2 is now open while
the other two switches are now closed, completing
their circuits.
A lever on the back of the switch is used to set the
switch into the ªadjustedº position. A non-adjusted
switch will have the lever set to the diagonal position
in relation to the switch housing. The plunger can be
moved in and out, but the states of the internal
switches will not change.
CAUTION: Never move the adjustment lever of the
new brake lamp switch without it being properly
installed in the vehicle first. Such action will render
the switch unusable and the switch must be dis-
carded.
Once installed in the vehicle as described in the
brake lamp switch installation procedure (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
BRAKE LAMP SWITCH - INSTALLATION), the new
switch's adjustment lever is rotated to the adjusted
position as indicated (Fig. 4). This action locks the
plunger to the internal switches.Once in this posi-
tion the switch is permanently adjusted (or
8L - 4 LAMPS/LIGHTING - EXTERIORRS
LAMPS/LIGHTING - EXTERIOR (Continued)
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Page 422 of 2177
(4) Disconnect CHMSL electrical connector from
bulb socket (Fig. 7).
INSTALLATION
(1) Connect electrical connector to CHMSL bulb
socket.
(2) Reconnect the rear window washer nozzle
assembly.
(3) Install the retaining screws.
(4) Reconnect the battery negative cable.
FRONT FOG LAMP
DIAGNOSIS AND TESTING - FRONT FOG LAMP
When a vehicle experiences problems with the
front fog lamp system, verify the condition of the bat-
tery connections, fuses, charging system, fog lamp
bulbs, wire connectors, relay, high beam switch, and
headlamp switch. Refer to the appropriate wiring
information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.Fig. 6 REAR WASHER NOZZLE ASSEMBLY
1 - BARREL IN CHMSL
2 - NOZZLE ASSEMBLY
3 - SQUEEZE ARMS TO RELEASE NOZZLE ASSEMBLY
4 - HOSE
Fig. 7 CHMSL ELECTRICAL CONNECTOR
1 - CHMSL UNIT
2 - CHMSL ELECTRICAL CONNECTOR
RSLAMPS/LIGHTING - EXTERIOR8L-7
CENTER HIGH MOUNTED STOP LAMP UNIT (Continued)
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FRONT FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery
System.
6. Poor lighting circuit Z349/Z248
ground.6. Test for voltage drop across Z349/248
ground locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS
BURN OUT
FREQUENTLY1. Charging system output too
high.1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
FOG LAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Poor lighting circuit Z349/Z248
ground.2. Test for voltage drop across Z349/Z248
ground locations. Refer to Electrical, Wiring
Information.
3. High resistance in fog lamp
circuit.3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH
RANDOMLY1. Poor lighting circuit Z349/Z248
ground.1. Test for voltage drop across Z349/Z248
ground locations. Refer to Electrical, Wiring
Information.
2. Variable resistance in fog lamp
circuit.2. Test amperage draw of fog lamp circuit.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
5. Is relay engaging properly? 5. Verify function of fog lamp relay in IPM.
6. PCI Bus Communication. 6. Verify PCI bus message (fog lamp info)
transmitted from BCM and received by FCM.
FOG LAMPS DO NOT
ILLUMINATE1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Electrical, Wiring
Information.
2. No Z349/Z248 ground at fog
lamps.2. Repair circuit ground. Refer to Electrical,
Wiring Information.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Broken connector terminal or
wire splice in fog lamp circuit.4. Repair connector terminal or wire splice.
5. Faulty or burned out bulb. 5. Replace bulb.
6. Is relay engaging? 6. Verify function of fog lamp relay in IPM.
7. PCI Bus Communication. 7. Verify PCI bus message (fog lamp info)
transmitted from BCM and received by FCM.
8L - 8 LAMPS/LIGHTING - EXTERIORRS
FRONT FOG LAMP (Continued)
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HEADLAMP
DIAGNOSIS AND TESTING - HEADLAMP
When a vehicle experiences problems with the
headlamp system, verify the condition of the battery
connections, fuses, charging system, headlamp bulbs,
wire connectors, relay, high beam switch, dimmer
switch, and headlamp switch. Refer to the appropri-
ate wiring information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Fig. 11 FOG LAMP UNIT ALIGNMENT - EXPORT
1 - HIGH INTENSITY AREA 4 - 200 MM
2 - CENTER OF VEHICLE 5 - 10 METERS
3 - HORIZONTAL CENTER OF FOG LAMP UNIT 6 - FRONT OF FOG LAMP UNIT
Fig. 12 FRONT POSITION LAMP
1 - TURN SIGNAL LAMP
2 - HIGH BEAM LAMP
3 - FRONT POSITION LAMP
4 - LOW BEAM LAMP
RSLAMPS/LIGHTING - EXTERIOR8L-11
FRONT POSITION LAMP - EXPORT (Continued)
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Page 503 of 2177
ered. This defeats the day-detect logic. If OK, go to
Step 8. If not OK, replace the faulty mirror unit.
(8) With the mirror darkened, place the transmis-
sion gear selector lever in the Reverse position. The
automatic day/night mirror should return to its nor-
mal reflectance. If not OK, replace the faulty mirror
unit.
Bench testing both mirrors can be done, of care is
exercised. For an inside mirror, the pin closest to he
mount is 12V (+), the next is 12V (-). The third is
reverse override. The fourth is outside mirror (+),
and the fifth is outside mirror (-).Do not apply 12
volts to the fourth and fifth pins.With 12 volts
on pins 1 and 2, the mirror can be tested by blocking
the rear sensor and shining a light into the forward
sensor. For an outside mirror, there is a 2±pin con-
nector. Applying 1.2 volts will cause the mirror to
dim. If the mirror does not dim, the entire glass
assembly can be replaced just as it is when the glass
is broken.
WARNING: Do not apply 12 volts to the outside mir-
ror. Damage to the mirror will result.
POWER FOLDAWAY MIRROR
SWITCH - EXPORT
DESCRIPTION
These vehicles may be equipped with Power Fold-
away Mirrors. This feature allows both the driver
and passenger side view mirrors to fold inward
(retract) on demand. The vehicle has an additional
switch located on the steering column that controls
the folding function of the mirror assembly (Fig. 2).
The fold-away side view mirror is attached to the
vehicle's door in the same manner as mirrors without
the fold-away option. The fold-away mirrors unique
option is the internal motor which allows the mirrors
to fold inward on demand. The fold-away mirror
motor is not serviceable separately and if a motor is
found to be faulty the entire side view mirror must
be replaced.
OPERATION
When the mirror retract switch is depressed, both
of the side view mirrors will fold inward, Thus mak-
ing the overall width of the vehicle the smallest pos-
sible. This can be helpful were parking space is a
absolute minimum.
When the driver's door is opened, only the driver's
door mirror will unfold. If the passenger door is
opened, both mirrors will unfold.
The power fold away mirror system consists of the
following components: mirror switch, side view mir-ror, relay, wires and fuse. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, details of wire harness routing and
retention, connector pin-out information and location
views for the various wire harness connectors, splices
and grounds.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the upper and lower steering column
shroud (Refer to 19 - STEERING/COLUMN/LOWER
SHROUD - REMOVAL).
(3) Disconnect electrical harness connector.
(4) Remove switch from steering column shroud
(Fig. 3).
Fig. 2 POWER FOLDAWAY MIRROR SWITCH
1 - POWER FOLDAWAY MIRROR SWITCH
2 - STEERING COLUMN
Fig. 3 POWER FOLDING MIRROR SWITCH
1 - STEERING COLUMN SHROUD
2 - POWER FOLDAWAY SWITCH
8N - 48 POWER MIRRORSRS
AUTOMATIC DAY / NIGHT MIRROR (Continued)
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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 toWiring Diagramsfor complete circuit
diagrams. Following are descriptions, theory of oper-
ation, diagnosis/testing procedures and removal/in-
stallation procedures of the major components in the
memory and power seat systems.
OPERATION
OPERATION - POWER SEAT SYSTEM
The power seat system receives battery current
through fuse #22 in the Intelligent Power Module
and a circuit breaker under the front seats, regard-
less of the ignition switch position.
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 appropri-
ate power seat track adjuster motor. The selected
adjuster motor operates to move the seat track
through its drive unit in the selected direction until
the switch is released, or until the travel limit of the
seat track 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 seat track has reached its travel
limit. The power seat track each contain a self-reset-
ting circuit breaker to protect them from overload.
However, consecutive or frequent resetting of the cir-
cuit breaker must not be allowed to continue, or the
motor may be damaged. Refer to 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) receives
battery current through fuse #22 in the Intelligent
Power Module and the power seat system circuit
breaker, located under the driver side front seat near
the rear edge of the seat cushion pan. The memory
system does not operate with the Ignition-Off Draw
(IOD) fuse removed. The MSMM will drive a maxi-
mum of 2 motors at a time in a given direction. If
conflicting directions are requested, the priority for
response will be approximately as follows:
²Seat Track Rearward or Forward
²Seat Front Down or Up
²Seat Rear Down or Up
²Recliner Rearward or ForwardThe 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.
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 MSMM,
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 DRBIIItscan tool
and the proper Diagnostic Procedures manual are
recommended.
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
DIAGNOSIS AND TESTING - POWER SEAT
SYSTEM
Following are tests that will help to diagnose the
hard wired components and circuits of the power seat
system. 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 DRBIIItscan tool
and the proper Diagnostic Procedures manual. The
DRBIIItscan 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.
8N - 52 POWER SEAT SYSTEMRS
POWER SEAT SYSTEM (Continued)
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Page 508 of 2177
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.
(1) If the vehicle is equipped with the memory sys-
tem and the driver side power seat exhibits a inter-
rupted or jerky motion, there is a possibility that the
wires leading from the memory seat module to the
memory seat motor are mis-wired. To check the con-
cern, obtain a DRBIIItscan tool and energize each
axis one at a time. If any axis stops in approximately
2 seconds (without hitting the end of travel), the
feedback for that axis may have an open, short or be
mis-wired. Check the wiring to that axis (module to
motor). Fix any wiring problems and retry that axis.
(2) If any power seat is not operational in any
direction, check the power seat circuit breaker,
located under the trailing edge of the driver side
power seat. Refer to the Power Distribution section of
this service manual for the circuit breaker diagnosis
and testing procedure.
(3) If the power seat circuit breaker is OK, check
for proper battery and ground connections at the
power seat switch and/or memory seat module. Fix
any wiring problems and retry.
(4) Check the power seat system wire harness con-
nections and pins to ensure proper circuit continuity
and ground paths. For complete circuit diagrams,
refer toWiring Diagrams.
(5) 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 in the power
seat system.
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 provideconfirmation 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.
(1) If the driver power seat exhibits a interrupted
or jerky motion, there is a possibility that the wires
leading from the memory seat module to the memory
seat motor are mis-wired. To check the concern,
obtain a DRB IIItscan tool and energize each axis
one at a time. If any axis stops in approximately 2
seconds (without hitting the end of travel), the feed-
back for that axis may have an open, short or be mis-
wired. Check the wiring to that axis (module to
motor). Fix any wiring problems and retry that axis.
Refer to Wiring Diagrams for complete circuit sche-
matic or connector pin-out information.
DRIVER SEAT SWITCH
DESCRIPTION
Vehicles equipped with a driver side power seat
utilize an 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
Fig. 2 Power Seat Switch Location
1 - Power Seat Switch
2 - Seat Cushion Side Shield
RSPOWER SEAT SYSTEM8N-53
POWER SEAT SYSTEM (Continued)
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