1999 DODGE NEON sensor

WATER PUMP DIAGNOSIS
A quick flow test to tell whether or not the pump is
working is to see if the heater warms properly. A
defective pump will not be able to circulate heated
coolant through the long heater hose.
Another flow test to help determine pump opera-
tion.
WARNING: DO NOT remove radiator cap if the cool-
ing system is hot or under pressure.
(1) Remove radiator cap.
(2) Remove a small amount of coolant from the
system, start the engine and warm up until thermo-
stat opens. With the thermostat open and coolant
level low you will see if the water pump is pumping
coolant through the system.
COOLING SYSTEM FLOW CHECK
To determine whether coolant is flowing through
the cooling system, use the following procedures:
(1) If engine is cold, idle engine until normal oper-
ating temperature is reached. Then feel the upper
radiator hose. If it is hot, coolant is circulating.
WARNING: DO NOT REMOVE THE COOLING SYS-
TEM PRESSURE CAP WITH THE SYSTEM HOT AND
UNDER PRESSURE BECAUSE SERIOUS BURNS
FROM COOLANT CAN OCCUR.
(2) Remove pressure cap when engine is cold,
remove small amount of coolant Idle engine until
thermostat opens, you should observe coolant flow
while looking down the filler neck. Once flow is
detected install the pressure cap.
RADIATOR FAN CONTROL
Fan control is accomplished two ways. The fan
always runs when the air conditioning compressor
clutch is engaged. In addition to this control, the fan
is turned on by the temperature of the coolant which
is sensed by the coolant temperature sensor which
sends the message to the Powertrain Control Module
(PCM). The (PCM) turns on the fan through the
Solid State Fan Relay. The Solid State Fan Relay is
located on the left front inner frame just behind the
radiator. See Wiring Diagrams Manual for circuity
and diagnostics provided.
Switching through the (PCM) provides fan control
for the following conditions.
²The fan will not run during cranking until the
engine starts no matter what the coolant tempera-
ture is.
²Fan will run when the air conditioning clutch is
engaged and low pressure cutout switch is closed.
²Fan will run at vehicle speeds above about 40
mph only if coolant temperature reaches 110ÉC(230ÉF). It will turn off when the temperature drops
to 104ÉC (220ÉF). At speeds below 40 mph the fan
switches on at 102ÉC (215ÉF) and off at 93ÉC (200ÉF).
Refer to Radiator Fan Control Module Group 14,
Fuel Injection for more information.
ELECTRIC FAN MOTOR TEST
Refer to Powertrain Diagnostic Manual for procedure.
TESTING COOLING SYSTEM FOR LEAKS
The system should be full. With the engine not
running, wipe the filler neck sealing seat clean.
Attach a radiator pressure tester to the filler neck,
as shown in (Fig. 9) and apply 104 kPa (15 psi) pres-
sure. If the pressure drops more than 2 psi in 2 min-
utes, inspect the system for external leaks.
Move all hoses at the radiator and heater while
system is pressurize at 15 psi, since some leaks occur
due to engine rock while driving.
If there are no external leaks after the gauge dial
shows a drop in pressure, detach the tester. Start the
engine, and run the engine to normal operating tem-
perature in order to open the thermostat and allow
the coolant to expand. Reattach the tester. If the nee-
dle on the dial fluctuates it indicates a combustion
leak, usually a head gasket leak.
WARNING: WITH THE PRESSURE TESTER IN
PLACE PRESSURE BUILDS UP QUICKLY. ANY
EXCESSIVE PRESSURE BUILD-UP DUE TO CON-
TINUOUS ENGINE OPERATION MUST BE
RELEASED TO A SAFE PRESSURE POINT. NEVER
PERMIT PRESSURE TO EXCEED 138 kPa (20 psi).
If the needle on the dial does not fluctuate, race
the engine a few times. If an abnormal amount of
coolant or steam is emitted from the tail pipe, it may
indicate a faulty head gasket, cracked engine block,
or cracked cylinder head.
Fig. 9 Pressure Testing Cooling SystemÐTypical
7 - 14 COOLINGPL
DIAGNOSIS AND TESTING (Continued)

BATTERY
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION......................... 1
DESCRIPTION AND OPERATION
BATTERY IGNITION OFF DRAW (IOD)........ 1
CHARGING TIME REQUIRED............... 1
DIAGNOSIS AND TESTING
BATTERY BUILT-IN TEST INDICATOR........ 2
BATTERY IGNITION OFF DRAW (IOD)........ 3
BATTERY LOAD TEST..................... 5
BATTERY OPEN CIRCUIT VOLTAGE TEST..... 6
BATTERY TEMPERATURE SENSOR.......... 6
SERVICE PROCEDURES
BATTERY CHARGING..................... 6CHARGING COMPLETELY DISCHARGED
BATTERY............................. 7
VISUAL INSPECTION..................... 7
REMOVAL AND INSTALLATION
BATTERY TRAY.......................... 9
BATTERY............................... 8
FRESH AIR INLET TUBE REMOVAL.......... 9
SPECIFICATIONS
BATTERY SPECIFICATIONS............... 10
TORQUE.............................. 10
GENERAL INFORMATION
INTRODUCTION
The battery stores, stabilizes, and delivers electri-
cal current to operate various electrical systems in
the vehicle. The determination of whether a battery
is good or bad is made by its ability to accept a
charge. It also must supply high-amperage current
for a long enough period to be able to start the vehi-
cle. The capability of the battery to store electrical
current comes from a chemical reaction. This reac-
tion takes place between the sulfuric acid solution
(electrolyte) and the lead +/- plates in each cell of the
battery. As the battery discharges, the plates react
with the acid from the electrolyte. When the charging
system charges the battery, the water is converted to
sulfuric acid in the battery. The concentration of acid
in the electrolyte is measured as specific gravity
using a hydrometer. The original equipment (OE)
battery is equipped with a hydrometer (test indica-
tor) built into the battery cover. The specific gravity
indicates the battery's state-of-charge. The OE bat-
tery is sealed and water cannot be added.
The battery is vented to release gases that are cre-
ated when the battery is being charged and dis-
charged. The battery top, posts, and terminals should
be cleaned when other under hood maintenance is
performed.
When the electrolyte level is below the top of the
plates, Yellow/Clear in the test Indicator, the battery
must be replaced. The battery must be completely
charged, and the battery top, posts, and cable clampsmust be cleaned before diagnostic procedures are per-
formed.DESCRIPTION AND OPERATION
BATTERY IGNITION OFF DRAW (IOD)
A completely normal vehicle will have a small
amount of current drain on the battery with the key
out of the ignition. It can range from 4 to 10 milli-
amperes after all the modules time out. If a vehicle
will not be operated for approximately a 20 days, the
IOD fuse should be disconnected to minimize the
vehicle electrical drain on the battery. The IOD fuse
is located in the Power Distribution Center (PDC).
Refer to the PDC to locate the cover proper fuse.
CHARGING TIME REQUIRED
WARNING: NEVER EXCEED 20 AMPS WHEN
CHARGING A COLD -1ÉC (30ÉF) BATTERY. PER-
SONAL INJURY MAY RESULT.
The time required to charge a battery will vary
depending upon the following factors.
SIZE OF BATTERY
A completely discharged large heavy-duty battery
may require more recharging time than a completely
discharged small capacity battery. Refer to Battery
Charging Timetable for proper charging times.
PLBATTERY 8A - 1

exposure over the preceding several hours. If the bat-
tery has been charged or boosted a few minutes prior
to the test, the battery would be slightly warmer.
Refer to Battery Load Test Temperatures Table for
proper voltage/temperature reading:
(6) If battery passes load test, it is in good condi-
tion and further tests are not necessary. If it fails
load test, it should be replaced.
BATTERY OPEN CIRCUIT VOLTAGE TEST
An open circuit voltage no load test shows the
state of charge of a battery and whether it is ready
for a load test at 50 percent of the battery's cold
crank rating. Refer to Battery Load Test. If a battery
has open circuit voltage reading of 12.4 volts or
greater, and will not pass the load test, replace the
battery because it is defective. To test open circuit
voltage, perform the following operation.
(1) Remove both battery cables, negative cable
first. Battery top, cables and posts should be clean. If
green dot is not visible in indicator, charge the bat-
tery. Refer to Battery Charging Procedures.
(2) Connect a Volt/Ammeter/Load tester to the bat-
tery posts (Fig. 7). Rotate the load control knob of theCarbon pile rheostat to apply a 300 amp load. Apply
this load for 15 seconds to remove the surface charge
from the battery, and return the control knob to off
(Fig. 8).
(3) Allow the battery to stabilize for 2 minutes,
and then verify the open circuit voltage (Fig. 10).
(4) This voltage reading will approximate the state
of charge of the battery. It will not reveal battery
cranking capacity. Refer to Battery Open Circuit
Voltage Table.
BATTERY TEMPERATURE SENSOR
For Battery Temperature Sensor refer to Group 8C
Generator.
SERVICE PROCEDURES
BATTERY CHARGING
A battery is considered fully charged when it will
meet all the following requirements.
²It has an open circuit voltage charge of at least
12.4 volts.
²It passes the 15 second load test. Refer to Bat-
tery Load Test.
²The built in test indicator dot is GREEN (Fig.
1).
NOTE: The battery cannot be refilled with water, it
must be replaced.
Fig. 9 Load 50% Cold Crank Rating
BATTERY LOAD TEST TEMPERATURES
Minimum
VoltageTemperature
ÉF ÉC
9.6 volts 70É and above 21É and above
9.5 volts 60É 16É
9.4 volts 50É 10É
9.3 volts 40É 4É
9.1 volts 30É -1É
8.9 volts 20É -7É
8.7 volts 10É -12É
8.5 volts 0É -18É
Fig. 10 Testing Open Circuit Voltage
BATTERY OPEN CIRCUIT VOLTAGE
Open Circuit Volts Charge Percentage
11.7 volts or less 0%
12.0 volts 25%
12.2 volts 50%
12.4 volts 75%
12.6 volts or more 100%
8A - 6 BATTERYPL
DIAGNOSIS AND TESTING (Continued)

WARNING: DO NOT CHARGE A BATTERY THAT
HAS EXCESSIVELY LOW ELECTROLYTE LEVEL.
BATTERY MAY SPARK INTERNALLY AND
EXPLODE. EXPLOSIVE GASES FORM OVER THE
BATTERY. DO NOT SMOKE, USE FLAME, OR CRE-
ATE SPARKS NEAR BATTERY. DO NOT ASSIST
BOOST OR CHARGE A FROZEN BATTERY. BAT-
TERY CASING MAY FRACTURE. BATTERY ACID IS
POISON, AND MAY CAUSE SEVERE BURNS. BAT-
TERIES CONTAIN SULFURIC ACID. AVOID CON-
TACT WITH SKIN, EYES, OR CLOTHING. IN THE
EVENT OF CONTACT, FLUSH WITH WATER AND
CALL PHYSICIAN IMMEDIATELY. KEEP OUT OF
REACH OF CHILDREN.
CAUTION: Disconnect the battery NEGATIVE cable
first, before charging battery to avoid damage to
electrical systems. Lift the red battery boot cover
from the positive cable clamp. Do not exceed 16.0
volts while charging battery. Refer to the instruc-
tions supplied with charging equipment
Battery electrolyte may bubble inside of battery
case while being charged properly. If the electrolyte
boils violently, or is discharged from the vent holes
while charging, immediately reduce charging rate or
turn off charger. Evaluate battery condition. Battery
damage may occur if charging is excessive.
Some battery chargers are equipped with polarity
sensing devices to protect the charger or battery from
being damaged if improperly connected. If the bat-
tery state of charge is too low for the polarity sensor
to detect, the sensor must be bypassed for charger to
operate. Refer to operating instructions provided
with battery charger being used.
CAUTION: Charge battery until test indicator
appears green. Do not overcharge.
It may be necessary to jiggle the battery or vehicle
to bring the green dot in the test indicator into view.
After the battery has been charged to 12.4 volts or
greater, perform a load test to determine cranking
capacity. Refer to Battery Load Test in this Group. If
the battery passes the load test, the battery is OK to
use. If battery will not pass the load test, it must be
replaced. Properly clean and inspect battery hold
downs, tray, terminals, cables, posts, and top before
completing service.
CHARGING COMPLETELY DISCHARGED BATTERY
The following procedure should be used to recharge
a completely discharged battery. Unless procedure is
properly followed, a good battery may be needlessly
replaced. Refer to Battery Charging Rate Table for
proper charging time.(1) Measure the voltage at battery posts with a
voltmeter accurate to 1/10 volt (Fig. 11). If below 10
volts, charge current will be low, and it could take
some time before it accepts a current in excess of a
few milliamperes. Such low current may not be
detectable on amp meters built into many chargers.
(2) Connect charger leads. Some chargers feature
polarity protection circuitry that prevents operation
unless charger is connected to battery posts correctly.
A completely discharged battery may not have
enough voltage to activate this circuitry. This may
happen even though the leads are connected properly.
(3) Battery chargers vary in the amount of voltage
and current they provide. For the time required for
the battery to accept measurable charger current at
various voltages, refer to the Battery Charging Rate
table. If charge current is still not measurable after
charging times, the battery should be replaced. If
charge current is measurable during charging time,
the battery may be good, and charging should be
completed in the normal manner.
VISUAL INSPECTION
CAUTION: Do not allow baking soda solution to
enter vent holes, as damage to battery can result.
(1) Clean top of battery with a solution of warm
water and baking soda.
(2) Apply soda solution with a bristle brush and
allow to soak until acid deposits loosen (Fig. 12).
BATTERY CHARGING RATE
Voltage Hours
16.0 volts maximum up to 4 hours
14.0 to 15.9 volts up to 8 hours
13.9 volts or less up to 16 hours
Fig. 11 Voltmeter Accurate to 1/10 Volt (Connected)
PLBATTERY 8A - 7
SERVICE PROCEDURES (Continued)

CHARGING SYSTEM
CONTENTS
page page
GENERAL INFORMATION
OVERVIEW............................. 1
DESCRIPTION AND OPERATION
BATTERY TEMPERATURE SENSOR.......... 2
CHARGING SYSTEM OPERATION........... 1
ELECTRONIC VOLTAGE REGULATOR......... 2
GENERATOR............................ 2
DIAGNOSIS AND TESTING
BATTERY TEMPERATURE SENSOR.......... 8
CHARGING SYSTEM RESISTANCE TESTS..... 5CHARGING SYSTEM...................... 2
CURRENT OUTPUT TEST.................. 8
ON-BOARD DIAGNOSTIC SYSTEM TEST..... 10
REMOVAL AND INSTALLATION
BATTERY TEMPERATURE SENSOR......... 11
GENERATOR........................... 10
SPECIFICATIONS
GENERATOR RATINGS................... 12
TORQUE.............................. 12
GENERAL INFORMATION
OVERVIEW
The battery, starting, and charging systems oper-
ate with one another, and must be tested as a com-
plete system. In order for the vehicle to start and
charge properly, all of the components involved in
these systems must perform within specifications.
Group 8A covers the battery, Group 8B covers the
starting system, and Group 8C covers the charging
system. Refer to Group 8W - Wiring Diagrams for
complete circuit descriptions and diagrams. We have
separated these systems to make it easier to locate
the information you are seeking within this Service
Manual. However, when attempting to diagnose any
of these systems, it is important that you keep their
interdependency in mind.
The diagnostic procedures used in these groups
include the most basic conventional diagnostic meth-
ods to the more sophisticated On-Board Diagnostics
(OBD) built into the Powertrain Control Module
(PCM). Use of an induction ammeter, volt/ohmmeter,
battery charger, carbon pile rheostat (load tester),
and 12-volt test lamp may be required.
All OBD-sensed systems are monitored by the
PCM. Each monitored circuit is assigned a Diagnos-
tic Trouble Code (DTC). The PCM will store a DTC in
electronic memory for any failure it detects. See the
On-Board Diagnostics Test in Group 8C - Charging
System for more information.
DESCRIPTION AND OPERATION
CHARGING SYSTEM OPERATION
The charging system consists of:
²Generator
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch (refer to Group 8D, Ignition Sys-
tem for information)
²Battery (refer to Group 8A, Battery for informa-
tion)
²Battery temperature sensor
²Voltmeter (refer to Group 8E, Instrument Panel
and Gauges for information)
²Wiring harness and connections (refer to Group
8W, Wiring for information)
The charging system is turned on and off with the
ignition switch. When the ignition switch is turned to
the ON position, battery voltage is applied to the
generator rotor through one of the two field termi-
nals to produce a magnetic field. The generator is
driven by the engine through a serpentine belt and
pulley arrangement.
The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry,
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground.
PLCHARGING SYSTEM 8C - 1

A battery temperature sensor located on the front
bumper beam is used to sense battery temperature.
This temperature data, along with data from moni-
tored line voltage, is used by the PCM to vary the
battery charging rate. This is done by cycling the
ground path to control the strength of the rotor mag-
netic field. The PCM then compensates and regulates
generator current output accordingly and to maintain
the proper voltage depending on battery tempera-
ture.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including the
EVR (field control) circuitry, are monitored by the
PCM. Each monitored circuit is assigned a Diagnos-
tic Trouble Code (DTC). The PCM will store a DTC in
electronic memory for any failure it detects. See On-
Board Diagnostic System Test in this group for more
information.
GENERATOR
The generator is belt-driven by the engine. It is
serviced only as a complete assembly. If the genera-
tor fails for any reason, the entire assembly must be
replaced.
As the energized rotor begins to rotate within the
generator, the spinning magnetic field induces a cur-
rent into the windings of the stator coil. Once the
generator begins producing sufficient current, it also
provides the current needed to energize the rotor.
The Y type stator winding connections deliver the
induced AC current to 3 positive and 3 negative
diodes for rectification. From the diodes, rectified DC
current is delivered to the vehicle electrical system
through the generator, battery, and ground terminals.
Noise emitting from the generator may be caused
by:
²Worn, loose or defective bearings
²Loose or defective drive pulley
²Incorrect, worn, damaged or misadjusted drive
belt
²Loose mounting bolts
²Misaligned drive pulley
²Defective stator or diode
BATTERY TEMPERATURE SENSOR
The battery temperature sensor is used to deter-
mine the battery temperature. This temperature
data, along with data from monitored line voltage, is
used by the PCM to vary the battery charging rate.
System voltage will be higher at colder temperatures
and is gradually reduced at warmer temperatures.
The sensor is located on the bottom of the battery
tray (Fig. 1).
ELECTRONIC VOLTAGE REGULATOR
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
Operation:The amount of DC current produced
by the generator is controlled by EVR circuitry con-
tained within the PCM. This circuitry is connected in
series with the generators second rotor field terminal
and its ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage and bat-
tery temperature (refer to Battery Temperature Sen-
sor for more information). It then compensates and
regulates generator current output accordingly. Also
refer to Charging System Operation for additional
information.
DIAGNOSIS AND TESTING
CHARGING SYSTEM
When the ignition switch is turned to the ON posi-
tion, battery potential will register on the voltmeter.
During engine cranking a lower voltage will appear
on the meter. With the engine running, a voltage
reading higher than the first reading (ignition in ON)
should register.
The following are possible symptoms of a charging
system fault:
²The voltmeter does not operate properly
²An undercharged or overcharged battery condi-
tion occurs.
Fig. 1 Battery Temperature Sensor
8C - 2 CHARGING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

performed at each (- ground) connection in this cir-
cuit to locate the excessive resistance.
(7) Testing (+ positive) circuitry:
(a) Touch the positive lead of voltmeter directly
to battery negativePOST.
(b) Touch the negative lead of voltmeter to the
ground terminal stud on the generator case (not
the terminal mounting nut). Voltage should be no
higher than 0.3 volts. If voltage is higher than 0.3
volts, touch test lead to terminal mounting stud
nut and then to the wiring connector. If voltage is
now below 0.3 volts, look for dirty, loose or poor
connection at this point. A voltage drop test may be
performed at each (+ positive) connection in this
circuit to locate the excessive resistance. This test
can also be performed between the generator case
and the engine. If test voltage is higher than 0.3
volts, check for corrosion at generator mounting
points or loose generator mounting.
CURRENT OUTPUT TEST
The current output test will determine if the
charging system can deliver its minimum test cur-
rent (amperage) output. Refer to the Specifications
section at the end of this group for minimum test
current (amperage) requirements.
The first part of this test will determine the com-
bined amperage output of both the generator and the
Electronic Voltage Regulator (EVR) circuitry.
PREPARATION
(1) Determine if any Diagnostic Trouble Codes
(DTC) exist. To determine a DTC, refer to On-Board
Diagnostics in this group. For repair, refer to the
appropriate Powertrain Diagnostic Procedures man-
ual.
(2) Before starting test, make sure battery is in
good condition and is fully-charged. See Group 8A,
Battery for more information.
(3) Check condition of battery cables at battery.
Clean if necessary.
(4) Perform the Voltage Drop Test. This will
ensure clean and tight generator/battery electrical
connections.
(5) Be sure the generator drive belt is properly
tensioned. Refer to Group 7, Cooling System for
information.
(6) A volt/amp tester equipped with both a battery
load control (carbon pile rheostat) and an inductive-
type pickup clamp (ammeter probe) will be used for
this test. Refer to operating instructions supplied
with tester. When using a tester equipped with an
inductive-type clamp, removal of wiring at the gener-
ator will not be necessary.
(7) Start the engine and allow it to reach operating
temperature.
(8) Shut engine off.(9) Turn off all electrical accessories and all vehicle
lighting.
(10) Connect the volt/amp tester leads to the bat-
tery. Be sure the carbon pile rheostat control is in the
OPEN or OFF position before connecting leads. See
Load Test in Group 8A, Battery for more information.
Also refer to the operating instructions supplied with
test equipment.
(11) Connect the inductive clamp (ammeter probe).
Refer to the operating instructions supplied with test
equipment.
(12) If volt/amp tester is not equipped with an
engine tachometer, connect a separate tachometer to
the engine.
TEST
(1) Perform the previous test Preparation.
(2) Fully engage the parking brake.
(3) Start engine.
(4) Bring engine speed to 2500 rpm.
(5) With engine speed held at 2500 rpm, slowly
adjust the rheostat control (load) on the tester to
obtain the highest amperage reading. Do not allow
voltage to drop below 12 volts. Record the reading.
This load test must be performed within 15 sec-
onds to prevent damage to test equipment.On
certain brands of test equipment, this load will be
applied automatically. Refer to the operating manual
supplied with test equipment.
(6) The ammeter reading must meet the Minimum
Test Amps specifications as displayed in the Genera-
tor Ratings chart. This can be found in the Specifica-
tions section at the end of this group. A label stating
a part reference number is attached to the generator
case. On some engines this label may be located on
the bottom of the case. Compare this reference num-
ber to the Generator Ratings chart.
(7) Rotate the load control to the OFF position.
(8) Continue holding engine speed at 2500. If EVR
circuitry is OK, amperage should drop below 15±20
amps. With all electrical accessories and vehicle
lighting off, this could take several minutes of engine
operation. If amperage did not drop, refer to the
appropriate Powertrain Diagnostic Procedures man-
ual for testing.
(9) Remove volt/amp tester.
If minimum amperage could not be met, refer to
the appropriate Powertrain Diagnostic Procedures
manual for testing.
BATTERY TEMPERATURE SENSOR
To perform a complete test of this sensor and its
circuitry, refer to the appropriate Powertrain Diag-
nostic Procedures manual. To test the sensor only,
refer to the following:
(1) The sensor is located under the battery and is
attached to the battery tray (Fig. 5). A two-wire pig-
8C - 8 CHARGING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

tail harness is attached directly to the sensor. The
opposite end of this harness connects the sensor to
the engine wiring harness.
(2) Disconnect the two-wire pigtail harness from
the engine harness.
(3) Attach ohmmeter leads to the wire terminals of
the pigtail harness.
(4) At room temperature of 25É C (75±80É F), an
ohmmeter reading of 9,000 (9K) to 11,000 (11K) ohms
should be observed.
(5) If reading is above or below the specification,
replace the sensor.
(6) Refer to the Removal and Installation section
for procedures.
ON-BOARD DIAGNOSTIC SYSTEM TEST
GENERAL INFORMATION
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
Refer to Group 25, On Board Diagnostic for more
information. A DTC description can be read using the
DRB scan tool. Refer to the appropriate Powertrain
Diagnostic Procedures manual for information.
A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as asymptom, 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 DRB Scan Tool must be used to erase a DTC.
REMOVAL AND INSTALLATION
GENERATOR
REMOVAL
(1) Disconnect battery negative cable (Fig. 6).
(2) Loosen but DO NOT remove the generator
adjustment nut.
(3) Raise vehicle with front wheels turned fully to
the right.
(4) Remove the plastic lower splash shield.
(5) Disconnect the generator field circuit wiring
connector (Fig. 9). Squeeze locking tab to release.
(6) Remove the B+ terminal nut and wire.
(7) Loosen pivot bolt, but do not remove (Fig. 8)
and (Fig. 9).
(8) Remove the generator drive belt. The generator
spill shield does not need to be removed.
(9) Remove three mounting pivot bracket bolts.
(10) Remove pivot bolt and bracket.
(11) Holding the generator in one hand, remove
adjustment nut and slide the generator off the T-bolt.
The T-bolt does not need to be removed.
(12) Lower the generator and remove through the
wheel well.
INSTALLATION
(1) For installation, reverse above procedures. The
generator field connector has a locking tab and will
snap when fully installed. Refer to group 7 Cooling
System, Belt Removal/Install Adjust. Tighten all fas-
teners to the proper torque. Refer to the Torque Spec-
Fig. 5 Battery Temperature Sensor
Fig. 6 Removal/Installation of Battery Cables
8C - 10 CHARGING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)