check engine DODGE TOWN AND COUNTRY 2001 Manual Online

DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTIC SYSTEM
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the OBD system. Some
circuits are checked continuously and some are
checked only under certain conditions.
If the OBD system senses that a monitored circuit
is bad, it will put a DTC into electronic memory. The
DTC will stay in electronic memory as long as the
circuit continues to be bad. The PCM is programmed
to clear the memory after 50 engine starts if the
problem does not occur again.
DIAGNOSTIC TROUBLE CODES
A DTC description can be read using the DRBt
scan tool. Refer to the appropriate Powertrain Diag-
nostic Procedures manual for information.
A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as a
symptom, not as the cause for the problem. In some
cases, because of the design of the diagnostic test
procedure, a DTC can be the reason for another DTC
to be set. Therefore, it is important that the test pro-cedures be followed in sequence, to understand what
caused a DTC to be set.
ERASING DIAGNOSTIC TROUBLE CODES
The DRBIIItScan Tool must be used to erase a
DTC.
SPECIFICATIONS
GENERATOR
Type Engine Minimun Test
Amperage
Denso 2.4 L 135 Amp
Denso 3.3/3.8L 135 Amp or 160
Amp
Test Specification:
1. Engine RPM : 2500 RPM620 RPM
2. Voltage Output : 14.0 V60.5 V
3. Field Current : 5 amps60.1 amps
Part number is located on the side of the generator.
TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Battery Hold Down Clamp
Bolt20 14.7 180
Generator B+ Nut 12.4 9.2 110
Battery Terminal Nut 4 35
Generator Mounting Bolt
2.4L28.2 20.8 250
Starter Solenoid Battery
Nut 3.3/3.8L54.2 40
Generator Decoupler 109.8 81
8F - 22 CHARGINGRS
CHARGING (Continued)
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²Battery- Visually inspect the battery for indi-
cations of physical damage and loose or corroded
cable connections. Determine the state-of-charge and
cranking capacity of the battery. Charge or replace
the battery, if required. Refer to the Battery section
for more information.
²Ignition Switch- Visually inspect the ignition
switch for indications of physical damage and loose
or corroded wire harness connections.
²Transmission Range Sensor- Visually inspect
the transmission range sensor for indications of phys-
ical damage and loose or corroded wire harness con-
nections.
²Starter Relay- Visually inspect the starter
relay for indications of physical damage and loose or
corroded wire harness connections.²Starter- Visually inspect the starter for indica-
tions of physical damage and loose or corroded wire
harness connections.
²Starter Solenoid- Visually inspect the starter
solenoid for indications of physical damage and loose
or corroded wire harness connections.
²Wiring- Visually inspect the wire harness for
damage. Repair or replace any faulty wiring, as
required. Check for loose or corroded wire harness
connections at main engine ground and remote jump
post.
²Power Distribution Center (PDC)- Visually
inspect the B+ connections at the PDC for physical
damage and loose or corroded harness connections.
STARTING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
STARTER FAILS
TO ENGAGE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERYSECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY, IF
REQUIRED.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO FEED CIRCUIT RESISTANCE TEST AND FEED
CIRCUIT TEST IN THIS SECTION.
3. STARTER RELAY
FAULTY.3. REFER TO RELAY TEST, IN THIS SECTION. REPLACE
RELAY, IF NECESSARY.
4. IGNITION SWITCH
FAULTY.4. REFER TO IGNITION SWITCH TEST, IN THE STEERING
SECTION OR 8 WIRING DIAGRAMS. REPLACE SWITCH, IF
NECESSARY.
5. PARK/NEUTRAL
POSITION SWITCH
(AUTO TRANS) FAULTY
OR MIS-ADJUSTED.5. REFER PARK/NEUTRAL POSITION SWITCH TEST, IN THE
TRANSAXLE. SECTION FOR MORE INFORMATION. REPLACE
SWITCH, IF NECESSARY.
6. CLUTCH PEDAL
POSITION SWITCH
(MAN TRANS) FAULTY.6. REFER TO CLUTCH PEDAL POSITION SWITCH TEST, IN
THE CLUTCH. SECTION. REPLACE SWITCH, IF NECESSARY.
7. STARTER SOLENOID
FAULTY.7. REFER TO SOLENOID TEST, IN THIS SECTION. REPLACE
STARTER ASSEMBLY, IF NECESSARY.
8. STARTER ASSEMBLY
FAULTY.8. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
9. FAULTY TEETH ON
RING GEAR.9. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
STARTER
ENGAGES,
FAILS TO TURN
ENGINE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERY SECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY AS
NECESSARY.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO THE FEED CIRCUIT RESISTANCE TEST AND
THE FEED CIRCUIT TEST IN THIS SECTION. REPAIR AS
NECESSARY.
8F - 28 STARTINGRS
STARTING (Continued)
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CONDITION POSSIBLE CAUSE CORRECTION
3. STARTER ASSEMBLY
FAULTY.3. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
4. ENGINE SEIZED. 4. REFER TO THE ENGINE SECTION, FOR DIAGNOSTIC AND
SERVICE PROCEDURES.
5. LOOSE
CONNECTION AT
BATTERY, PDC,
STARTER, OR ENGINE
GROUND.5. INSPECT FOR LOOSE CONNECTIONS.
6. FAULTY TEETH ON
RING GEAR.6. ROTATE FLYWHEEL 360É, AND INSPECT TEETHAND RING
GEAR REPLACED IF DAMAGED.
STARTER
ENGAGES,
SPINS OUT
BEFORE
ENGINE
STARTS.1. BROKEN TEETH ON
STARTER RING GEAR.1. REMOVE STARTER. INSPECT RING GEAR AND REPLACE
IF NECESSARY.
2. STARTER ASSEMBLY
FAULTY.2. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
STARTER DOES
NOT
DISENGAGE.1. STARTER
IMPROPERLY
INSTALLED.1. INSTALL STARTER. TIGHTEN STARTER MOUNTING
HARDWARE TO CORRECT TORQUE SPECIFICATIONS.
2. STARTER RELAY
FAULTY.2. REFER TO RELAY TEST, IN THIS SECTION. REPLACE
RELAY, IF NECESSARY.
3. IGNITION SWITCH
FAULTY.3. REFER TO IGNITION SWITCH TEST, IN THE STEERING
SECTION.. REPLACE SWITCH, IF NECESSARY.
4. STARTER ASSEMBLY
FAULTY.4. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
5. FAULTY TEETH ON
RING GEAR.5. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
CONTROL CIRCUIT TEST
The starter control circuit has:
²Starter motor with integral solenoid
²Starter relay
²Transmission range sensor, or Park/Neutral
Position switch with automatic transmissions
²Ignition switch
²Battery
²All related wiring and connections
²Powertrain Control Module (PCM)
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.
²To disable ignition and fuel systems, disconnect
the Automatic Shutdown Relay (ASD). The ASD relay
is located in the Power Distribution Center (PDC).
Refer to the PDC cover for the proper relay location.
STARTER SOLENOID
WARNING: CHECK TO ENSURE THAT THE TRANS-
MISSION IS IN THE PARK POSITION WITH THE
PARKING BRAKE APPLIED.
(1) Verify battery condition. Battery must be in
good condition with a full charge before performing
any starter tests. Refer to Battery Tests.
(2) Perform Starter Solenoid test BEFORE per-
forming the starter relay test.
(3) Perform a visual inspection of the starter/
starter solenoid for corrosion, loose connections or
faulty wiring.
(4) Locate and remove the starter relay from the
Power Distribution Center (PDC). Refer to the PDC
label for relay identification and location.
RSSTARTING8F-29
STARTING (Continued)
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(5) Connect a remote starter switch or a jumper
wire between the remote battery positive post and
terminal 87 of the starter relay connector.
(a) If engine cranks, starter/starter solenoid is
good. Go to the Starter Relay Test.
(b) If engine does not crank or solenoid chatters,
check wiring and connectors from starter relay to
starter solenoid for loose or corroded connections.
Particularly at starter terminals.
(c) Repeat test. If engine still fails to crank prop-
erly, trouble is within starter or starter mounted
solenoid, and replace starter.
STARTER RELAY
WARNING: CHECK TO ENSURE THAT THE TRANS-
MISSION IS IN THE PARK/NEUTRAL POSITION
WITH THE PARKING BRAKE APPLIED.
RELAY TEST
The starter relay is located in the Power Distribu-
tion Center (PDC) in the engine compartment. Refer
to the PDC label for relay identification and location.
Remove the starter relay from the PDC as
described in this group to perform the following tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 7565 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery B+ lead to terminals 86 and
a ground lead to terminal 85 to energize the relay.
The relay should click. Also test for continuity
between terminals 30 and 87, and no continuity
between terminals 87A and 30. If OK, refer to Relay
Circuit Test procedure. If not OK, replace the faulty
relay.
CAV FUNCTION
30 B (+)
85 P/N POSITION SW.SENSE
(AUTO)
86 IGNITION SWITCH
OUTPUT
87 STARTER RELAY OUTPUT
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the PDC fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the starter solenoid field coils. There should be
continuity between the cavity for relay terminal 87
and the starter solenoid terminal at all times. If OK,
go to Step 4. If not OK, repair the open circuit to the
starter solenoid as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is energized when
the ignition switch is held in the Start position.
Check for battery voltage at the cavity for relay ter-
minal 86 with the ignition switch in the Start posi-
tion, and no voltage when the ignition switch is
released to the On position. If OK, go to Step 5. If
not OK, check for an open or short circuit to the igni-
tion switch and repair, if required. If the circuit to
the ignition switch is OK, see the Ignition Switch
Test procedure in this group.
Starter Relay Pinout
Starter Relay Pinout
8F - 30 STARTINGRS
STARTING (Continued)
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(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the transmission range sensor only when the
gearshift selector lever is in the Park or Neutral
positions. Check for continuity to ground at the cav-
ity for relay terminal 85. If not OK with an auto-
matic transmission, check for an open or short circuit
to the transmission range sensor and repair.
SAFETY SWITCHES
For diagnostics of the Transmission Range Sensor,
refer to the Transaxle section for more information.
If equipped with Clutch Interlock/Upstop Switch,
refer to Diagnosis and Testing in the Clutch section.
IGNITION SWITCH
After testing starter solenoid and relay, test igni-
tion switch and wiring. Refer to the Ignition Section
or Wiring Diagrams for more information. Check all
wiring for opens or shorts, and all connectors for
being loose or corroded.
BATTERY
For battery diagnosis and testing, refer to the Bat-
tery section for procedures.
ALL RELATED WIRING AND CONNECTORS
Refer to Wiring Diagrams for more information.
FEED CIRCUIT RESISTANCE TEST
Before proceeding with this operation, review Diag-
nostic Preparation and Starter Feed Circuit Tests.
The following operation will require a voltmeter,
accurate to 1/10 of a volt.
CAUTION: Ignition and Fuel systems must be dis-
abled to prevent engine start while performing the
following tests.
(1) To disable the Ignition and Fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location.
(2) Remove the air cleaner assembly for access to
battery terminals. Refer to the Fuel section for ser-
vice procedures.
(3) With all wiring harnesses and components
properly connected, perform the following:
(a) Connect the negative lead of the voltmeter to
the battery negative post, and positive lead to the
battery negative cable clamp. Rotate and hold the
ignition switch in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between cable clamp and post.(b) Connect positive lead of the voltmeter to the
battery positive post, and negative lead to the bat-
tery positive cable clamp. Rotate and hold the igni-
tion switch key in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between the cable clamp and post.
(c) Connect negative lead of voltmeter to battery
negative terminal, and positive lead to engine
block near the battery cable attaching point.
Rotate and hold the ignition switch in the START
position. If voltage reads above 0.2 volt, correct
poor contact at ground cable attaching point. If
voltage reading is still above 0.2 volt after correct-
ing poor contacts, replace ground cable.
(4) Connect positive voltmeter lead to the starter
motor housing and the negative lead to the battery
negative terminal. Hold the ignition switch key in
the START position. If voltage reads above 0.2 volt,
correct poor starter to engine ground.
(a) Connect the positive voltmeter lead to the
battery positive terminal, and negative lead to bat-
tery cable terminal on starter solenoid. Rotate and
hold the ignition switch in the START position. If
voltage reads above 0.2 volt, correct poor contact at
battery cable to solenoid connection. If reading is
still above 0.2 volt after correcting poor contacts,
replace battery positive cable.
(b) If resistance tests do not detect feed circuit
failures, replace the starter motor.FEED CIRCUIT TEST
NOTE: The following results are based upon the
vehicle being at room temperature.
The following procedure will require a suitable
volt-ampere tester (Fig. 2).
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.
Fig. 2 Volt Ampere Tester
RSSTARTING8F-31
STARTING (Continued)
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(1) Check battery before performing this test. Bat-
tery must be fully charged.
(2) Connect a volt-ampere tester to the battery ter-
minals. Refer to the operating instructions provided
with the tester being used.
(3) To disable the ignition and fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location.
(4) Verify that all lights and accessories are OFF,
and the transmission shift selector is in the PARK
and SET parking brake.
CAUTION: Do not overheat the starter motor or
draw the battery voltage below 9.6 volts during
cranking operations.
(5) Rotate and hold the ignition switch in the
START position. Observe the volt-ampere tester (Fig.
2).
²If voltage reads above 9.6 volts, and amperage
draw reads above 280 amps, check for engine seizing
or faulty starter.
²If voltage reads 12.4 volts or greater and amper-
age reads 0 to 10 amps, check for corroded cables
and/or bad connections.
²Voltage below 9.6 volts and amperage draw
above 300 amps, the problem is the starter. Replace
the starter refer to starter removal.
(6) After the starting system problems have been
corrected, verify the battery state-of-charge and
charge battery if necessary. Disconnect all testingequipment and connect ASD relay. Start the vehicle
several times to assure the problem has been cor-
rected.
SPECIFICATIONS
STARTER
MANUFACTURER NIPPONDENSO
Engine Application 2.4L /3.3/3.8L
Power rating 1.2 Kw
Voltage 12 VOLTS
No. of Fields 4
No. of Poles 4
Brushes 4
Drive Conventional Gear Train
Free running Test
Voltage 11
Amperage Draw 73 Amp
Minimum Speed 3401 RPM
SolenoidClosing Voltage 7.5 Volts
Cranking Amperage Draw
test150 - 200 Amps.
Engine should be up to operating temperature.
Extremely heavy oil or tight engine will increase
starter amperage draw.
Torques
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Starter Mounting Bolts 47.4 35
Starter Solenoid Battery
Nut11.3 8.3 100
8F - 32 STARTINGRS
STARTING (Continued)
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Spiral plate technology is the process by which the
plates holding the active material in the battery are
wound tightly in coils instead of hanging flat, like
conventional batteries. This design has a lower inter-
nal resistance and also increases the active material
surface area.
WARNING: NEVER EXCEED 14.4 VOLTS WHEN
CHARGING A SPIRAL PLATE BATTERY. PERSONAL
INJURY AND/OR BATTERY DAMAGE MAY RESULT.
Due to the maintanance-free design, distilled water
cannot be added to this battery. Therefore, if more
than 14.4 volts are used during the spiral plate bat-
tery charging process, water vapor can be exhausted
through the pressure-sensitive battery vents and lost
for good. This can permanently damage the spiral
plate battery. Never exceed 14.4 volts when charging
a spiral plate battery. Personal injury and/or battery
damage may result.
CONVENTIONAL BATTERY - GASOLINE ENGINE
Low-maintenance conventional batteries are used
on vehicles equipped with a gasoline engine, these
batteries have removable battery cell caps (Fig. 2).
Watercanbe added to this battery. Under normal
service, the composition of this battery reduces gas-
sing and water loss at normal charge rates. Howeverthese batteries may require additional distilled water
after years of service.
Conventional batteries are made up of six individ-
ual cells that are connected in series. Each cell con-
tains positive charged plate groups made of lead
oxide, and negatively charged plate groups made of
sponge lead. The plates are submerged in a sulfuric
acid and water solution called electrolyte.
Both batteries are used to store electrical energy
potential in a chemical form. When an electrical load
is applied to the battery terminals, an electrochemi-
cal reaction occurs within the battery. This reaction
causes the battery to discharge electrical current.
Refer to the RS service information for additional
Battery System information.
STANDARD PROCEDURE - CHECKING BATTERY
ELECTROLYTE LEVEL
The following procedure can be used to check the
electrolyte level in a lead-acid battery.
(1) Unscrew and remove the battery cell caps with
a flat-bladed screw driver (Fig. 3).
WARNING: NEVER PUT YOUR FACE NEAR A GAS-
SING, HOT OR SWELLED BATTERY. SERIOUS PER-
SONAL INJURY MAY RESULT.
(2) Wearing safety glasses, look through the bat-
tery cell cap holes to determine the level of the elec-
trolyte in the battery. The electrolyte should be above
the hooks inside the battery cells (Fig. 4).
Fig. 2 BATTERY CELL CAP REMOVAL/
INSTALLATION - LOW-MAINTANANCE GASOLINE
ENGINE BATTERY
1 - BATTERY CELL CAP
2 - BATTERY CASE
Fig. 3 BATTERY CELL CAP REMOVAL/
INSTALLATION- CONVENTIONAL BATTERY ONLY
1 - BATTERY CELL CAP
2 - BATTERY CASE
8Fa - 2 BATTERY SYSTEM - RG ONLYRG
BATTERY (Continued)
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HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION............................5
OPERATION.............................5
DIAGNOSIS AND TESTING..................5
HEATED MIRROR TEST...................5
MIRROR SWITCH
DESCRIPTION............................5OPERATION.............................5
HEATED MIRROR GRID
STANDARD PROCEDURE...................6
HEATED MIRROR.......................6
RELAY
DESCRIPTION............................6
HEATED MIRRORS
DESCRIPTION
Heated mirrors are available on models with
Power Mirrors and Rear Window Defogger only.
OPERATION
The heated mirror is controlled by the rear window
defogger switch. The heated mirror is ON when the
rear window defogger is ON (Fig. 1)
DIAGNOSIS AND TESING - HEATED MIRROR
TEST
Heated mirrors are available on models with
Power Mirrors and Rear Window Defogger only. The
heated mirror is controlled by the rear window defog-
ger switch. The heated mirror is ON when the rear
window defogger is ON.
(1) The mirror glass should be warm to the touch.
(2) If not, check the 20 amp fuse (11) in the Power
Distribution Center (PDC) part of the Integrated
Power Module (IPM) in the engine compartment.
(3) Test voltage at rear window defogger switch.
²If no voltage repair wire.
²Remove mirror glass and test the wires for con-
tinuity. If no continuity repair wires.
²If wires are OK, replace mirror glass.
²To test defogger switch refer to the appropriate
section in Electrical.
MIRROR SWITCH
DESCRIPTION
The heated mirror switch is integrated into the
rear window defogger switch located in the HVAC
control panel (Fig. 1)
OPERATION
A LED indicator will illuminate when the switch is
activated. The switch energizes the HVAC control
assembly when it requests the Front Control Module
(FCM) to activate the rear window defogger relay.
The relay controls the current to flow to the grids of
the rear window defogger, heated power side view
mirrors and the heated windshield wiper de-icer. The
defogger relay will be on for approximately 10 min-
utes or until the control switch or ignition is turned
off.
Fig. 1 HVAC CONTROL PANEL
1 - Trim Bezel
2 - ACT Sensor
3 - A/C Request Switch
4 - Rear Window Defogger/Heated Mirrors Switch Combo
5 - Front Window Defroster Mode Selector
RSHEATED MIRRORS8G-5
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HORN
TABLE OF CONTENTS
page page
HORN
DESCRIPTION............................1
OPERATION.............................1
DIAGNOSIS AND TESTING..................1
HORN
DIAGNOSIS AND TESTING..................3
REMOVAL...............................4INSTALLATION............................5
HORN RELAY
DIAGNOSIS AND TESTING..................5
REMOVAL...............................5
INSTALLATION............................5
HORN SWITCH
DESCRIPTION............................5
HORN
DESCRIPTION
HORN SYSTEM
WARNING:
ON VEHICLES EQUIPPED WITH AIRBAG, REFER TO
ELECTRICAL, RESTRAINTS FOR SAFETY PRECAU-
TIONS. DISCONNECT THE NEGATIVE CABLE FROM
THE BATTERY BEFORE SERVICING COMPONENTS
INVOLVING THE AIRBAG SYSTEM. ACCIDENTAL
DEPLOYMENT OF AIRBAG AND PERSONAL INJURY
CAN RESULT.
The horn circuit consists of a horn switch, clock-
spring, horn relay, horns and intelligent power mod-
ule. The horn switch is a membrane switch located in
the airbag trim cover. The horns are located forward
of the left front wheel behind the bumper fascia.
OPERATION
The horn relay plugs into the intelligent power
module which is located in the engine compartment.
For circuit information and component locations,
refer to the appropriate wiring information. The wir-
ing 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.
The horns will not function if the switch is
ªCLOSEDº for more than 30 seconds. Once the
switch is ªOPENº, a 20±30 second delay will occur
before the horns are functional again.
DIAGNOSIS AND TESTING
Refer to Horn System Test below. If the horn does
not sound, check horn fuse located in the intelligent
power module. If the fuse is blown, replace with the
correct fuse. If the horns fail to sound and the new
fuse blows when depressing the horn switch, a short
circuit in the horn or the horn wiring between the
fuse terminal and the horn is responsible, or a defec-
tive horn switch allowed the horn to burn out is
responsible.
If the fuse is OK, test horn relay (Refer to 8 -
ELECTRICAL/HORN/HORN RELAY - DIAGNOSIS
AND TESTING).
If the relay is OK, test horn. Refer to Horn System
Test.
CAUTION:
Continuous sounding of horn may cause horn relay
to fail.
Should the horn sound continuously:
²Unplug the horn relay from intelligent power
module.
²Refer to (Refer to 8 - ELECTRICAL/HORN/
HORN RELAY - DIAGNOSIS AND TESTING).
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.
RSHORN8H-1
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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 informs the PCM when the
ASD relay energizes. A 12 volt signal at this input
indicates to the PCM that the ASD has been acti-
vated. This input is used only to sense that the ASD
relay is energized.
When energized, the ASD relay supplies battery
voltage to the fuel injectors, ignition coils and the
heating element in each oxygen sensor. If the PCM
does not receive 12 volts from this input after
grounding the ASD relay, it sets a Diagnostic Trouble
Code (DTC).
When energized, the ASD relay provides power to
operate the injectors, ignition coil, generator field, O2
sensor heaters (both upstream and downstream), and
also provides a sense circuit to the PCM for diagnos-
tic purposes. The PCM energizes the ASD any time
there is a Crankshaft Position sensor signal that
exceeds a predetermined value. The ASD relay can
also be energized after the engine has been turned
off to perform 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.
The PCM still operates internally to perform several
checks, including monitoring the O2 sensor heaters.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
The camshaft position sensorfor the 3.3/3.8L is
mounted in the front of the timing case cover (Fig. 7)
and the camshaft position sensor for the 2.4L is
mounted on the end of the cylinder head (Fig. 4).
OPERATION
The camshaft position sensor provides cylinder
identification to the Powertrain Control Module
(PCM) (Fig. 2). The sensor generates pulses as
groups of notches on the camshaft sprocket pass
underneath it (Fig. 3). The PCM keeps track of
crankshaft rotation and identifies each cylinder by
the pulses generated by the notches on the camshaftsprocket. Four crankshaft pulses follow each group of
camshaft pulses.
When the PCM receives 2 cam pulses followed by
the long flat spot on the camshaft sprocket, it knows
that the crankshaft timing marks for cylinder 1 are
next (on driveplate). When the PCM receives one
camshaft pulse after the long flat spot on the
sprocket, cylinder number 2 crankshaft timing marks
are next. After 3 camshaft pulses, the PCM knows
cylinder 4 crankshaft timing marks follow. One cam-
shaft pulse after the 3 pulses indicates cylinder 5.
The 2 camshaft pulses after cylinder 5 signals cylin-
der 6 (Fig. 3). The PCM can synchronize on cylinders
1or4.
When metal aligns with the sensor, voltage goes
low (less than 0.3 volts). When a notch aligns with
the sensor, voltage switches high (5.0 volts). As a
group of notches pass under the sensor, the voltage
switches from low (metal) to high (notch) then back
to low. The number of notches determine the amount
of pulses. If available, an oscilloscope can display the
square wave patterns of each timing event.
Top Dead Center (TDC) does not occur when
notches on the camshaft sprocket pass below the cyl-
inder. TDC occurs after the camshaft pulse (or
pulses) and after the 4 crankshaft pulses associated
with the particular cylinder. The arrows and cylinder
call outs on Figure 4 represent which cylinder the
flat spot and notches identify, they do not indicate
TDC position.
REMOVAL - 2.4L
The camshaft position sensor is mounted to the
rear of the cylinder head.
(1) Remove the negative battery cable.
Fig. 2 Camshaft Position Sensor
1 - ELECTRICAL CONNECTOR
2 - O-RING
3 - PAPER SPACER
RSIGNITION CONTROL8I-3
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