background image

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 negative POST .

(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 previous Output Wire Resistance

Test (voltage drop test) (Fig. 5). This will ensure
clean and tight generator/battery electrical connec-
tions.

(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.

8C - 8

CHARGING SYSTEM

PL

DIAGNOSIS AND TESTING (Continued)

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 ...

Reviews: