Page 77 of 1395

R'oR
l
u
'98 -'9O modols: Alternator Contlol SYstem Te3t (U.S.A' model)
NOTE: Before testing, check proper operation of the ELD by checking for a DTC (see section 11)
EATTERY
CAUTION: Be surc to uso a voltmetorwith its oo3itive torminel connccted to
battery po3hivo tnd its negativo teami'
nal to the 4P connector torminal No 2.
ECM,/PCM CONNECTORc {31P)
Wire side olfemale terminals
cIWHT/GRN)
Wire side oltemale terminals
ALTERNATOR4P CONNECTOR
ALTC
IWHT/GBNI
ECM/PCM CONNECTOR C {31P}
(cont'd)
Chock tor . short in tha circuit
IALTC lino):1. Disconnoct the 4P connectorIrom the alternator.2. Start the engine, and turn the
headlights (high beam) ON.
3. Measure voltage between the4P connector terminal No. 2
and the positive terminal oIthe battsry.
lsthere 1V or less?
Check for an opon in the wire
IALTC line):1. Turn the headlight and igni-
tion switch OFF.2. Disconnect the 31P connectorfrom the ECM/PCM.3. Check tor continuity betweenth6 ECM/PCM 31P connectorterminal No. 2 and alternator4P connector terminal No. 2.
Ropair open in the wiro betweenthe ahornrtor and ECM/PCM.
Chack lor a rhort in tho wire
{ALTC lincl:'!. Turn the headlight and igni'tion switch OFF.2. Disconnect the 31P connectorIrom the ECM/PCM.3. Ch6ck for continuity betweenthe ECM/PCM 31P connectorterminal No. 2 and bodyground.
Substituto . known-good ECM/
PCM, .nd rochock.lf prdcdb€d voltage b now av.il-able, repl.ce the original ECM/
rcM.
Rcpair rhort in thc wire b.twconth. ahGrn.tol.nd the EcM/PcM.
4-27
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Page 78 of 1395

Gharging System
Troubleshooting (cont'd)
Alternator/Regulator Test
NOTE: Make sure the battery is sufficiently charged (see section 23).
FIELDSELECTOR
TESTswtTcH
I
VOLTMEIERPOSmVEt
NEGATIVE TESTERCABI.E {BLKI
(BED)
TESTERINDUCTIVEPICK.UP{GRN)CABLE IREDIAhernator/Regulator Test (cont'd)lI Release the accelerator pedal,and let the engine idle.2 Make sure all accessories areturned off. Turn the selectorswitch to posjtion 2 (charging).3 Remove the inductive pick up,and zero the ammeter.{ Place the inductive pick-upover the battery ground cableso that the arrow points to thebaftery negative terminal.5. Raise the engine speed to2 000 rpm, and hold ir there.
I
(
T
I
WHT WIRE
Alternator/Regulator Test:1. Connect a Sun VAT-40 (orequrvalent tester), and turnthe selector switch to position1{sraning).2. Shift to neutral (A/T in E orN) position, and start theengane. Hold the engine at3,000 rpm with no load untilthe radiator fan comes on,then let it idle.3. Raise the engine speed to2,000 rpm, and hold it there.
ls the voltage over 15.1 V?
ls the voltage less than 13.5 V?
Altarnator/Regulator Test (cont'd:Apply a load with a VAT-40 untilthe battery voltage drops tobetween 12 - 13.5 V.
To next page
4-28
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Page 79 of 1395
From previous page
The charging sy3tem b OK.ls the amperage 65 A or more?
Aharnator/Regulator Tesl (cont'd):
With the engine speed still at
2.000 rom, fulllield the alternator.
CAUTION: The voh.ge will tise quickly whon th. ahornato. is tull-li.lded Do not allow
the voltage to exceod 18 V; it mry damago the .loctrictl 3yaiGm.
NOTE: Attach a probe to a VAT-40Iull tield test lead, and inseft the probe into the tull field
access hole at the back of the altemator' Switch the field selector to the "A lGround)" posi-
tion momentarily. and check the amperage readrng.
REGULATOR(Located insidethe ond coverlFULL FIELDACCESS HOLE
4-29
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Page 80 of 1395
Charging System
Alternator Replacement
't.Disconnect the battery negative terminal first, thenthe positive terminal.
Disconnect the 4P (or 3P) connector and WHT wirefrom the alternator.
WHT WIRE
4-30
'll
Remove the adjusting bolt and mounting nut, thenremove the alternator belt.
Pull out the through bolt, then remove the alternator.
THROUGH BOLT
ll^I}v
N
ir
T
n
MOUNTING NUT10 x 1.25 mm44 N.m 14.5 kgf.m.33 tbtfttt
o.
LOCKNUT8 x 1 .25 mm24 N.m (2.4 kgt m, 17 lbl.ft,
Install the alternator in reverse order of removal.
Adjust the alternator belt tension after installation(see page 4-34).
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Page 81 of 1395
,T
Alternator Overhaul
NOTE: Do not remove the pulley unless the front bear-
ing needs replacement.
To loosen the pulley locknut, use the tools as shown. lf
necessary, use an impact wrench.
PULLEY LOCKNUT111 N.m (11.3 kgf.m,81.7 lbf.ft)
FRONT BEARING
CAUTION: Do not get grease
or oil on the slip rings.
BRUSH HOLDERINSULATOB
"'^.^t%THROUGH BOLT
PULLEY
PULLEY LOCKNUT111 N.m {11.3 kgf.m, 81.7 lbf,ft)RECTIFIERASSYTest. page 4 32
PULLEY
BEARING INSULATOR
COVER
REAR HOUSING
4-31
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Page 82 of 1395

Charging System
IRectifier Test
NOTE: The diodes are designed to allow current to pass
in one direction while blocking it in the opposite direc
tion. Since the alternator rectifier is made up of eight
diodes (four pairs), each diode must be tested for continuity in both directions with an ohmmeter that has diode
checking capability; a total of 16 checks.
'l. Check for continuity in each direction between- the B and P terminals.- E (ground) and P terminals.
All diodes should have continuity in only one direc-
tion.
2. lf any of the diodes fails, replace the rectifier assem-
bly. (Diodes are not available separatelv.)
4-32
1.
Alternator Brush Inspection
2.
Remove the end cover, then take out the brush holder
by removing its two screws.
Measure the length of the brushes with a vernier
calrper.
Alternator Brush Length:
Standard (Newl:10.5 mm 10.41 inl
Service Limit: 1.5 mm {0.06 in)
lf the brushes are less than the service limit, replace
the alternator brush assemblv.
VERNIER CALIPER
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Page 83 of 1395
Rotor Slip Ring Test
1. Check the resistance between the slip rings.
There should be 1.8 - 3.0 ohms.
. lf resistance meets the specification, go to step 2
. lf resistance does not meet the specification,
replace the alternator.
SLIP RINGS
Check that there is no continuity between the slip
rings and the rotor or rotor shaft.
lf the rotor fails either continuity check, replace the
alternator.
ROTOR SHAFT
4-33
Stator Test
1. Check that there is continuity between each pair of
leads.
Check that there is no continuity between each lead
and the coil core.
It the coil fails either continuity check, replace the
alternator.
LEADS
corL coRE
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Page 84 of 1395
Charging System
Alternator Belt Inspection and Adjustment
NOTE: When using a new belt, first adjust the deflectionor tension to the values for the new belt, then readjustthe deflection or tension to the values for the used beltafter running engine for five minutes.
Deflection methodi
Apply a force of 98 N (10 kgt,22lbll, and measure thedeflection between the alternator and crankshaft pulley.
Detlection:
Used Belt:8.5 - 11.5 mm (0.33 - 0.45 inlNew Beft: 5.5 - 8.0 mm 10.22 - 0.31 inl
NOTEr lf the belt is worn or damaged, replace it.
Measure here
4-34
Belt tension gauge m6thod:
Attach the belt tension gauge to the belt and measure thetension. Follow the gauge manufacturer's instructions.
Tension:
Used Belt:340 - /€0 N (35 - 50 kgf, 77 - 1r0 tbf)New Belt: 690 - 880 N (70 - 90 kgf, 150 - 200 tbt)
NOTE: lfthe belt is worn or damaged, replace it.
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