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CHARGING SYSTEM

CONTENTS

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GENERAL INFORMATION

OVERVIEW

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DESCRIPTION AND OPERATION

BATTERY TEMPERATURE SENSOR . . . . . . . . . 2
CHARGING SYSTEM OPERATION

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ELECTRONIC VOLTAGE REGULATOR

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GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

DIAGNOSIS AND TESTING

BATTERY TEMPERATURE SENSOR

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CHARGING SYSTEM RESISTANCE TESTS . . . . 7

CHARGING SYSTEM . . . . . . . . . . . . . . . . . . . . . 2
CURRENT OUTPUT TEST . . . . . . . . . . . . . . . . . 8
ON-BOARD DIAGNOSTIC SYSTEM TEST

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REMOVAL AND INSTALLATION

BATTERY TEMPERATURE SENSOR

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GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . 11

SPECIFICATIONS

GENERATOR RATINGS . . . . . . . . . . . . . . . . . . 13
TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . 13

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:

Generator

Electronic Voltage Regulator (EVR) circuitry

within the Powertrain Control Module (PCM)

Ignition switch (refer to Group 8D, Ignition Sys-

tem for information)

Battery (refer to Group 8A, Battery for informa-

tion)

Battery temperature sensor

Voltmeter (refer to Group 8E, Instrument Panel

and Gauges for information)

Wiring 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.

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

PL

CHARGING SYSTEM

8C - 1

Summary of Contents for Neon PL 1997

Page 1: ...ed 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 Generator Electronic Voltage Regulator EVR ...

Page 2: ...warmer temperatures The sensor is located forward of the vehicle battery and is attached to 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...

Page 3: ...y Replace battery if electrolyte level is low 4 Inspect generator mounting bolts for tightness Replace or tighten bolts if required Refer to the Gen erator Removal Installation section of this group for torque specifications 5 Inspect generator drive belt condition and ten sion Tighten or replace belt as required Refer to Belt Tension Specifications in Group 7 Cooling Sys tem 6 Inspect automatic b...

Page 4: ...Charging System Schematic Typical 8C 4 CHARGING SYSTEM PL DIAGNOSIS AND TESTING Continued ...

Page 5: ...OLTS YES CLEAN MOUNTING SUR FACES TIGHTEN FASTENERS TO SPECIFIED TORQUE NO CHECK ON BOARD DIAG NOSTIC TROUBLE CODES DTC PERFORM OUTPUT VOLT AGE TEST YES LOW OR NO CHARGING VOLTAGE OR DTC 41 OR 47 NO REFER TO VOLTAGE DROP TEST NO CHARGING SYSTEM AND GENERATOR IS OK CHARGING VOLTAGE ABOVE MAXIMUM OR DTC 41 OR 46 REFER TO LOAD TEST VOLTAGE YES REFER TO OVERCHARGE TEST PL CHARGING SYSTEM 8C 5 DIAGNOSI...

Page 6: ...UT VOLTAGE TEST DISCONNECT FIELD TERMINAL MEASURE RESISTANCE FROM K20 CIRCUIT ON WIRING HAR NESS TO ENGINE GROUND YES IS RESISTANCE LESS THAN 1000 OHMS NO REPAIR SHORT TO GROUND MEASURE RESISTANCE FROM K20 TERMINAL ON GENERATOR TO ENGINE GROUND REPLACE GENERATOR YES IS RESISTANCE LESS THAN 1000 OHMS NO REPEAT OUTPUT VOLTAGE TEST 8C 6 CHARGING SYSTEM PL DIAGNOSIS AND TESTING Continued ...

Page 7: ...erature 4 Shut engine off 5 Connect an engine tachometer 6 Fully engage the parking brake TEST 1 Start engine 2 Place heater blower in high position 3 Turn on headlamps and place in high beam position 4 Turn vehicle interior lamps on 5 Start engine Bring engine speed up to 2400 rpm and hold 6 Testing ground circuitry a Touch the negative lead of voltmeter directly to battery positive POST Fig 4 b ...

Page 8: ...ating 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 ...

Page 9: ...EN NO CHECK FOR BLOWN FUSE LINK NO IF LESS THAN 5 OHMS IF GREATER THAN 5 OHMS MEASURE VOLTAGE AT K 20 TERMI NAL ON THE GENERATOR YES YES REPAIR WIRE DISCONNECT FIELD CONNECTOR REPLACE PCM REPLACE GENERATOR YES VOLTAGE AT K 20 LESS THAN 10 VOLTS REPEAT OUTPUT VOLTAGE TEST CHECK SHORT CIRCUIT IN WIRE REPAIR FUSE LINK AND WIRE SHORT REFER TO GROUP 8W WIRING DIA GRAMS YES SHORT CIRCUIT IN FEED WIRE NO...

Page 10: ...ure 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 Th...

Page 11: ...llows 1 Lamp on for 2 seconds then turns off 2 Lamp flashes 4 times pauses and then flashes 1 time 3 Lamp pauses for 4 seconds flashes 4 times pauses then flashes 7 times 4 The two DTC s are 41 and 47 Any number of DTC s can be displayed as long as they are in mem ory The lamp will flash until all stored DTC s are displayed then it will flash a DTC 55 to indicate the test is complete ERASING DIAGN...

Page 12: ...EMPERATURE SENSOR REMOVAL 1 Make sure ignition switch is in OFF position and all accessories are OFF 2 Remove battery negative cable first then the positive cable Fig 12 3 Remove battery thermoguard Fig 13 WARNING TO PROTECT THE HANDS FROM BAT TERY ACID A SUITABLE PAIR OF HEAVY DUTY RUBBER GLOVES NOT THE HOUSEHOLD TYPE SHOULD BE WORN WHEN REMOVING OR SERVIC ING A BATTERY SAFETY GLASSES ALSO SHOULD...

Page 13: ... m 75 in lbs Battery Hold Down Clamp Bolt 9 N m 75 in lbs Generator Mounting Bolt 54 N m 40 ft lbs Generator Pivot Bolt 54 N m 40 ft lbs Fig 15 Battery Temperature Sensor Connector BATTERY TRAY BATTERY TEMPERATURE SENSOR AIR INLET TUBE TYPE PART NUMBER RATED SAE AMPS ENGINES MINIMUM TEST AMPS MELCO 4793190 83 AMPS 2 0L SOHC DOHC 75 AMPS PL CHARGING SYSTEM 8C 13 REMOVAL AND INSTALLATION Continued ...

Page 14: ......

Page 15: ...CHARGING SYSTEM CONTENTS page DIAGNOSIS AND TESTING CHARGING SYSTEM 2 PL CHARGING SYSTEM 8C 1 ...

Page 16: ...DIAGNOSIS AND TESTING CHARGING SYSTEM INSPECTION Charging System Test 8C 2 CHARGING SYSTEM PL ...

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