2001 DODGE TOWN AND COUNTRY air condition

OPERATION - SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the Powertrain Control Module
(PCM).
OPERATION - SCI RECEIVE - PCM INPUT
SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Control Module (PCM) receives data from the DRB
through the SCI Receive circuit.
OPERATION - IGNITION SENSE - PCM INPUT
The ignition sense input informs the Powertrain
Control Module (PCM) that the ignition switch is in
the crank or run position.
OPERATION - PCM GROUND
Ground is provided through multiple pins of the
PCM connector. Depending on the vehicle there may
be as many as three different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground
side of any relay, solenoid, ignition coil or injector.
The signal ground is used for any input that uses
sensor return for ground, and the ground side of any
internal processing component.
The SBEC III case is shielded to prevent RFI and
EMI. The PCM case is grounded and must be firmly
attached to a good, clean body ground.
Internally all grounds are connected together, how-
ever there is noise suppression on the sensor ground.
For EMI and RFI protection the case is also
grounded separately from the ground pins.
OPERATION - 8-VOLT SUPPLY - PCM OUTPUT
The PCM supplies 8 volts to the crankshaft posi-
tion sensor, camshaft position sensor.
OPERATION - 5 VOLT SUPPLY - PCM OUTPUT
The PCM supplies 5 volts to the following sensors:
²A/C pressure transducer
²Engine coolant temperature sensor
²Manifold absolute pressure sensor
²Throttle position sensor
²Linear EGR solenoid
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 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
RSELECTRONIC CONTROL MODULES8E-19
POWERTRAIN CONTROL MODULE (Continued)
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²Fuel system monitor
²EGR monitor
²Purge system monitor
²All inputs monitored for proper voltage range.
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.
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 sense
²Battery voltage
²Battery temperature
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.
DECELERATION MODE
This is a CLOSED LOOP mode. During decelera-
tion the following inputs are received by the PCM:
²A/C sense
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
²IAC motor 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. 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.
The PCM does not monitor the heated oxygen sen-
sor inputs during wide-open-throttle operation except
for downstream heated oxygen sensor and both
shorted diagnostics. The PCM adjusts injector pulse
width to supply a predetermined amount of addi-
tional fuel.
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.
STANDARD PROCEDURES - OBTAINING
DIAGNOSTIC TROUBLE CODES
BULB CHECK
Each time the ignition key is turned to the ON
position, the malfunction indicator (check engine)
lamp on the instrument panel should illuminate for
approximately 2 seconds then go out. This is done for
a bulb check. When the key is in the power on, but
engine off position, the MIL will remain illuminated
for regulatory purposes.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
(2) Turn the ignition switch on and access the
ªRead Faultº screen.
(3) Record all the DTC's and ªfreeze frameº infor-
mation shown on the DRB scan tool.
RSELECTRONIC CONTROL MODULES8E-21
POWERTRAIN CONTROL MODULE (Continued)
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BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY SEEMS
WEAK OR DEAD WHEN
ATTEMPTING TO START
THE ENGINE.1. The battery has an
incorrect size or rating for
this vehicle.1. Refer to Battery Specifications for the proper
size and rating. Replace an incorrect battery, as
required.
2. The battery is physically
damaged.2. Inspect the battery for loose terminal posts or a
cracked and leaking case. Replace the damaged
battery, as required.
3. The battery terminal
connections are loose or
corroded.3. Refer to Battery Cable for the proper cable
diagnosis and testing procedures. Clean and
tighten the battery terminal connections, as
required.
4. The battery is discharged. 4. Determine the battery state-of-charge. Refer to
Standard Procedures for the proper test
procedures. Charge the faulty battery, as
required.
5. The electrical system
ignition-off draw is excessive.5. Refer to Standard Procedures for the proper
test procedures. Repair the faulty electrical
system, as required.
6. The battery is faulty. 6. Determine the battery cranking capacity. Refer
to Standard Procedures for the test procedures.
Replace the faulty battery, as required.
7. The starting system is
faulty.7. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
8. The charging system is
faulty.8. Determine if the charging system is performing
to specifications. Refer to Charging System for
the proper charging system diagnosis and testing
procedures. Repair the faulty charging system, as
required.
RSBATTERY SYSTEM8F-3
BATTERY SYSTEM (Continued)
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BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY STATE OF
CHARGE CANNOT BE
MAINTAINED.1. The battery has an
incorrect size or rating for
this vehicle.1. Refer to Battery Specifications for the proper
specifications. Replace an incorrect battery, as
required.
2. The battery terminal
connections are loose or
corroded.2. Refer to Battery Cable for the proper cable
diagnosis and testing procedures. Clean and
tighten the battery terminal connections, as
required.
3. The generator drive belt is
slipping.3. Refer to Cooling System for the proper
accessory drive belt diagnosis and testing
procedures. Replace or adjust the faulty
generator drive belt, as required.
4. The electrical system
ignition-off draw is excessive.4. Refer to Standard Procedures for the proper
test procedures. Repair the faulty electrical
system, as required.
5. The battery is faulty. 5. Determine the battery cranking capacity. Refer
to Standard Procedures for the proper test
procedures. Replace the faulty battery, as
required.
6. The starting system is
faulty.6. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
7. The charging system is
faulty.7. Determine if the charging system is performing
to specifications. Refer to Charging System for
the proper charging system diagnosis and testing
procedures. Repair the faulty charging system, as
required.
8. Electrical loads exceed the
output of the charging
system.8. Inspect the vehicle for aftermarket electrical
equipment which might cause excessive electrical
loads.
9. Slow driving or prolonged
idling with high-amperage
draw systems in use.9. Advise the vehicle operator, as required.
THE BATTERY WILL NOT
ACCEPT A CHARGE.1. The battery is faulty. 1. Refer to Standard Procedures for the proper
battery charging procedures. Charge or replace
the faulty battery, as required.
ABNORMAL BATTERY DISCHARGING
Any of the following conditions can result in abnor-
mal battery discharging:
²Corroded or loose battery posts and terminal
clamps.
²A loose or worn generator drive belt.
²Electrical loads that exceed the output of the
charging system. This can be due to equipment
installed after manufacture, or repeated short trip
use.²Slow driving speeds (heavy traffic conditions) or
prolonged idling, with high-amperage draw systems
in use.
²A faulty circuit or component causing excessive
ignition-off draw.
²A faulty or incorrect charging system compo-
nent. Refer to Charging System for the proper charg-
ing system diagnosis and testing procedures.
8F - 4 BATTERY SYSTEMRS
BATTERY SYSTEM (Continued)
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REMOVAL - BATTERY
WARNING: A SUITABLE PAIR OF HEAVY DUTY
RUBBER GLOVES SHOULD BE WORN WHEN
REMOVING OR SERVICING A BATTERY.
WARNING: SAFETY GLASSES SHOULD BE WORN
WHEN REMOVING OR SERVICING A BATTERY.
WARNING: REMOVE METALLIC JEWELRY TO
AVOID INJURY BY ACCIDENTAL ARCING OF BAT-
TERY CURRENT.
(1) Verify that the ignition switch and all accesso-
ries are OFF.
(2) Disconnect the battery cables from the battery
posts, negative first (Fig. 15).
(3) Remove the battery hold down retaining nut.
(4) Remove the battery hold down bracket.
(5) Remove the battery from the vehicle.
INSTALLATION
(1) Position the battery in the battery tray.
(2) Install the battery hold down bracket and
retaining nut. Torque the nut to 20 N´m (180 in. lbs.).(3) Connect the battery cables to the battery posts,
positive cable first. Torque terminal fasteners to 8.5
N´m (75 in. lbs.).
BATTERY HOLDDOWN
DESCRIPTION
The battery hold down hardware consists of a
molded plastic lip that is integral to the outboard
edge of the battery tray and support unit, a molded
steel hold down bracket and a single hex nut with a
coned washer.
When installing a battery into the battery tray, be
certain that the hold down hardware is properly
installed and that the fasteners are tightened to the
proper specifications. Improper hold down fastener
tightness, whether too loose or too tight, can result in
damage to the battery, the vehicle or both. Refer to
Battery Hold Downsin this section of this service
manual for the location of the proper battery hold
down installation procedures, including the proper
hold down fastener tightness specifications.
OPERATION
The battery holddown secures the battery in the
battery tray. This holddown is designed to prevent
battery movement during the most extreme vehicle
operation conditions. Periodic removal and lubrica-
tion of the battery holddown hardware is recom-
mended to prevent hardware seizure at a later date.
NOTE: Never operate a vehicle without a battery
holddown device properly installed. Damage to the
vehicle, components and battery could result.
REMOVAL
All of the battery hold down hardware can be ser-
viced without removal of the battery or the battery
tray and support unit.
(1) Turn the ignition switch to the Off position. Be
certain that all electrical accessories are turned off.
(2) Remove the nut with washer that secures the
battery hold down bracket to the battery tray and
support unit.
(3) Remove the battery hold down bracket from
the battery tray and support unit.
INSTALLATION
(1) Install the battery hold down bracket in the
battery tray and support unit.
(2) Install the nut with washer that secures the
battery hold down bracket to the battery tray and
support unit. Torque to 20 N´m (180 in. lbs.).
Fig. 15 BATTERY POSITION & ORIENTATION
1 - BATTERY THERMAL GUARD
2 - INTELLIGENT POWER MODULE
3 - FRONT CONTROL MODULE
8F - 16 BATTERY SYSTEMRS
BATTERY (Continued)
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GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
4). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING -
CONDITION POSSIBLE CAUSES CORRECTION
Does not drive generator
(Generator not Charging)Clutch failure Replace Decoupler
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Raise vehicle and support.
(4) Remove the right front lower splash shield.
(5) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures (Fig. 5).
(6) Lower vehicle.
(7) Remove the Air Box, refer to the Engine section
for more information.
(8) Use Special Tool #8433 (Fig. 6) to loosen the
Generator Decoupler.
(9) Remove the tool.
(10) Remove the Generator Decoupler.
Fig. 4 GENERATOR DECOUPLER 3.3/3.8L
Fig. 5 DRIVE BELT 3.3/3.8L
RSCHARGING8F-25
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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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WINDSHIELD GRID
DIAGNOSIS AND TESTING - SYSTEM TEST
Electrically heated rear window defogger or the
heated windshield wiper deicer operation can be
checked on the vehicle in the following manner:
(1) Turn the ignition switch to the ON position.
(2) Using a ammeter on the battery, turn the rear
defogger control switch to the ON position, a distinct
increase in amperage draw should be noted.
(3) The rear window defogger or the heated wind-
shield wiper deicer operation can be checked by feel-
ing the glass. A distinct difference in temperature
between the grid lines and adjacent clear glass can
be detected in 3 to 4 minutes of operation.
(4) Using a DC voltmeter (Fig. 4) contact terminal
B with the negative lead, and terminal A with the
positive lead. The voltmeter should read 10-14 volts.
(5) Indicator light illumination means that there is
power available at the switch only and does not nec-
essarily verify system operation.
(6) If turning the defogger switch ON, no distinct
current draw on the ammeter the problem should be
isolated in the following manner:
²Confirm that ignition switch is ON.
²Ensure that the heated rear window or the
heated windshield wiper deicer feed pigtail is con-
nected to the wiring harness and that the ground
pigtail is in fact grounded.
²Ensure that the proper fuse in the PDC is OK.
(7) When the above steps have been completed and
the system is still inoperative it may be necessary to
connect a DRBIII scan tool and refer to the Diagnos-
tic Service Manual, you may also check for the fol-
lowing being defective:
²HVAC control assembly
²Rear window defogger relay in the IPM.
²Check for loose connector or a wire pushed out
of connector.
²Rear window or the windshield grid lines (all
grid lines would have to be broken, or one of the feed
pigtails not connected to the bus bar, for no ammeter
deflection).
(8) If turning the switch ON produces severe volt-
meter deflection, the circuit should be closely checked
for a shorting condition.
(9) If the system operation has been verified but
indicator LED does not light, replace the HVAC con-
trol assembly.
(10) For detailed wiring information, refer to the
appropriate section for Wiring Diagrams.
STANDARD PROCEDURE - GRID LINE AND
TERMINAL REPAIR
WARNING:
REPAIR KIT MAY CAUSE SKIN OR EYE IRRITATION.
CONTAINS EPOXY RESIN AND AMINE TYPE HARD-
ENER, HARMFUL IF SWALLOWED. AVOID CON-
TACT WITH SKIN AND EYES. FOR SKIN, WASH
AFFECTED AREAS WITH SOAP AND WATER. DO
NOT TAKE INTERNALLY. IF TAKEN INTERNALLY,
INDUCE VOMITING; CALL A PHYSICIAN IMMEDI-
ATELY. IF IN CONTACT WITH EYES, FLUSH WITH
PLENTY OF WATER. USE WITH ADEQUATE VENTI-
LATION. DO NOT USE NEAR FIRE OR FLAME. CON-
TENTS CONTAINS 3% FLAMMABLE SOLVENTS.
KEEP OUT OF REACH OF CHILDREN.
The repair for the front windshield or the rear win-
dow grids are the same.
The repair of grid lines and replacement of the ter-
minal is possible using the MopartRepair Package
or equivalent.
(1) Clean area surrounding grid line or terminal
by gently rubbing area with steel wool.
(2) Wipe area with clean cloth soaked in alcohol or
similar solvent. It is necessary that all contaminants
be removed from repair area.
Fig. 4 Grid Line Test
1 - VOLTMETER
2 - TERMINAL B
3 - FEED WIRE
4 - MID-POINT C (TYPICAL)
5 - HEATED REAR WINDOW GRIDS
6 - GROUND WIRE
7 - TERMINAL A
RSHEATED GLASS8G-3
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