•
Volt a ge is a pplied t o t h e fu el in ject or s wit h t h e
ASD r ela y via t h e P CM. Th e P CM will t h en a dju st
t h e in ject or pu lse widt h by t u r n in g t h e gr ou n d cir cu it
t o ea ch in dividu a l in ject or on a n d off.
•
Th e P CM m on it or s t h e O2S sen sor in pu t a n d
a dju st s a ir-fu el r a t io. It a lso a dju st s en gin e idle
speed t h r ou gh t h e idle a ir con t r ol (IAC) m ot or.
•
Th e P CM a dju st s ign it ion t im in g by t u r n in g t h e
gr ou n d pa t h t o t h e coil on a n d off.
•
Th e P CM oper a t es t h e A/C com pr essor clu t ch
t h r ou gh t h e clu t ch r ela y. Th is h a ppen s if A/C h a s
been select ed by t h e veh icle oper a t or a n d r equ est ed
by t h e A/C t h er m ost a t .
ACCELERATION MODE
Th is is a n Open Loop m ode. Th e power t r a in con t r ol
m odu le (P CM) r ecogn izes a n a br u pt in cr ea se in
t h r ot t le posit ion or MAP pr essu r e a s a dem a n d for
in cr ea sed en gin e ou t pu t a n d veh icle a cceler a t ion . Th e
P CM in cr ea ses in ject or pu lse widt h in r espon se t o
in cr ea sed t h r ot t le open in g.
DECELERATION MODE
Wh en t h e en gin e is a t oper a t in g t em per a t u r e, t h is
is a n Open Loop m ode. Du r in g h a r d deceler a t ion , t h e
power t r a in con t r ol m odu le (P CM) r eceives t h e follow-
in g in pu t s.
•
Air con dit ion in g select sign a l (if equ ipped)
•
Air con dit ion in g r equ est sign a l (if equ ipped)
•
Ba t t er y volt a ge
•
E n gin e coola n t t em per a t u r e sen sor
•
Cr a n ksh a ft posit ion sen sor
•
In t a ke m a n ifold a ir t em per a t u r e sen sor
•
Ma n ifold a bsolu t e pr essu r e (MAP ) sen sor
•
Th r ot t le posit ion sen sor (TP S)
•
Ca m sh a ft posit ion sen sor sign a l (in t h e dist r ibu -
t or )
•
P a r k/n eu t r a l swit ch (gea r in dica t or sign a l—a u t o.
t r a n s. on ly)
•
Veh icle speed sen sor
If t h e veh icle is u n der h a r d deceler a t ion wit h t h e
pr oper r pm a n d closed t h r ot t le con dit ion s, t h e P CM
will ign or e t h e oxygen sen sor in pu t sign a l. Th e P CM
will en t er a fu el cu t -off st r a t egy in wh ich it will n ot
su pply a gr ou n d t o t h e in ject or s. If a h a r d deceler a -
t ion does n ot exist , t h e P CM will det er m in e t h e
pr oper in ject or pu lse widt h a n d con t in u e in ject ion .
Ba sed on t h e a bove in pu t s, t h e P CM will a dju st
en gin e idle speed t h r ou gh t h e idle a ir con t r ol (IAC)
m ot or.
Th e P CM a dju st s ign it ion t im in g by t u r n in g t h e
gr ou n d pa t h t o t h e coil on a n d off.
WIDE OPEN THROTTLE MODE
Th is is a n Open Loop m ode. Du r in g wide open
t h r ot t le oper a t ion , t h e power t r a in con t r ol m odu le
(P CM) r eceives t h e followin g in pu t s.
•
Ba t t er y volt a ge
•
Cr a n ksh a ft posit ion sen sor
•
E n gin e coola n t t em per a t u r e sen sor
•
In t a ke m a n ifold a ir t em per a t u r e sen sor
•
Ma n ifold a bsolu t e pr essu r e (MAP ) sen sor
•
Th r ot t le posit ion sen sor (TP S)
•
Ca m sh a ft posit ion sen sor sign a l (in t h e dist r ibu -
t or )
Du r in g wide open t h r ot t le con dit ion s, t h e followin g
occu r s:
•
Volt a ge is a pplied t o t h e fu el in ject or s wit h t h e
ASD r ela y via t h e P CM. Th e P CM will t h en con t r ol
t h e in ject ion sequ en ce a n d in ject or pu lse widt h by
t u r n in g t h e gr ou n d cir cu it t o ea ch in dividu a l in ject or
on a n d off. Th e P CM ign or es t h e oxygen sen sor in pu t
sign a l a n d pr ovides a pr edet er m in ed a m ou n t of a ddi-
t ion a l fu el. Th is is don e by a dju st in g in ject or pu lse
widt h .
•
Th e P CM a dju st s ign it ion t im in g by t u r n in g t h e
gr ou n d pa t h t o t h e coil on a n d off.
IGNITION SWITCH OFF MODE
Wh en ign it ion swit ch is t u r n ed t o OF F posit ion ,
t h e P CM st ops oper a t in g t h e in ject or s, ign it ion coil,
ASD r ela y a n d fu el pu m p r ela y.
AIR CONDITIONING (A/C) CONTROLS—PCM
INPUT
OPERATION
Th e A/C con t r ol syst em in for m a t ion a pplies t o fa c-
t or y in st a lled a ir con dit ion in g u n it s.
A/C S ELECT S IGN AL:
Wh en t h e A/C swit ch is in
t h e ON posit ion , a n in pu t sign a l is sen t t o t h e P ow-
er t r a in Con t r ol Modu le (P CM). Th e sign a l in for m s
t h e P CM t h a t t h e A/C h a s been select ed. Th e P CM
a dju st s idle speed t o a pr e-pr ogr a m m ed r pm t h r ou gh
t h e idle a ir con t r ol (IAC) m ot or t o com pen sa t e for
in cr ea sed en gin e loa d.
A/C REQU ES T S IGN AL:
On ce A/C h a s been
select ed, t h e P CM r eceives t h e A/C r equ est sign a l
fr om t h e clu t ch cyclin g pr essu r e swit ch . Th e in pu t
in dica t es t h a t t h e eva por a t or pr essu r e is in t h e
pr oper r a n ge for A/C a pplica t ion . Th e P CM u ses t h is
in pu t t o cycle t h e A/C com pr essor clu t ch (t h r ou gh t h e
A/C r ela y). It will a lso det er m in e t h e cor r ect en gin e
idle speed t h r ou gh t h e idle a ir con t r ol (IAC) m ot or
posit ion .
If t h e A/C low-pr essu r e swit ch or h igh -pr essu r e
swit ch open s (in dica t in g a low or h igh r efr iger a n t
pr essu r e), t h e P CM will n ot r eceive a n A/C r equ est
sign a l. Th e P CM will t h en r em ove t h e gr ou n d fr om
X J
FUEL SYSTEM
14 - 27
DESCRI PT I ON AN D OPERAT I ON (Cont inue d)
Summary of Contents for Cherokee 1999
Page 1: ...HOFRPH WR WKH HHS KHURNHH OHFWURQLF 6HUYLFH 0DQXDO OLFN 2Q 7KH RJR 7R HJLQ...
Page 19: ...Fig 1 Wheel Alignment Measurements 2 2 SUSPENSION XJ GENERAL INFORMATION Continued...
Page 35: ......
Page 53: ...FRONT AXLES DIAGNOSIS 3 18 DIFFERENTIAL AND DRIVELINE XJ DIAGNOSIS AND TESTING Continued...
Page 54: ...DIAGNOSIS CONTINUED XJ DIFFERENTIAL AND DRIVELINE 3 19 DIAGNOSIS AND TESTING Continued...
Page 77: ...Fig 61 Gear Tooth Contact Patterns 3 42 DIFFERENTIAL AND DRIVELINE XJ ADJUSTMENTS Continued...
Page 86: ...DIAGNOSIS CHART XJ DIFFERENTIAL AND DRIVELINE 3 51 DIAGNOSIS AND TESTING Continued...
Page 87: ...DIAGNOSIS CHART CONTINUED 3 52 DIFFERENTIAL AND DRIVELINE XJ DIAGNOSIS AND TESTING Continued...
Page 112: ...Fig 79 Gear Tooth Contact Patterns XJ DIFFERENTIAL AND DRIVELINE 3 77 ADJUSTMENTS Continued...
Page 122: ...DIAGNOSIS CHART XJ DIFFERENTIAL AND DRIVELINE 3 87 DIAGNOSIS AND TESTING Continued...
Page 123: ...DIAGNOSIS CHART CONTINUED 3 88 DIFFERENTIAL AND DRIVELINE XJ DIAGNOSIS AND TESTING Continued...
Page 143: ...Fig 59 Gear Tooth Contact Patterns 3 108 DIFFERENTIAL AND DRIVELINE XJ ADJUSTMENTS Continued...
Page 185: ......
Page 189: ...Clutch Components 6 4 CLUTCH XJ DIAGNOSIS AND TESTING Continued...
Page 243: ......
Page 251: ...COOLING SYSTEM DIAGNOSIS DIESEL ENGINE 7 8 COOLING SYSTEM XJ DIAGNOSIS AND TESTING Continued...
Page 252: ...XJ COOLING SYSTEM 7 9 DIAGNOSIS AND TESTING Continued...
Page 253: ...7 10 COOLING SYSTEM XJ DIAGNOSIS AND TESTING Continued...
Page 254: ...XJ COOLING SYSTEM 7 11 DIAGNOSIS AND TESTING Continued...
Page 255: ...7 12 COOLING SYSTEM XJ DIAGNOSIS AND TESTING Continued...
Page 260: ...SERPENTINE DRIVE BELT DIAGNOSIS XJ COOLING SYSTEM 7 17 DIAGNOSIS AND TESTING Continued...
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Page 979: ...Fig 26 ABS G Sensor 8W 90 34 8W 90 CONNECTOR LOCA TIONS XJ DESCRIPTION AND OPERATION Continued...
Page 980: ...Fig 27 Rear Lamps XJ 8W 90 CONNECTOR LOCA TIONS 8W 90 35 DESCRIPTION AND OPERATION Continued...
Page 983: ...Fig 30 Liftgate 8W 90 38 8W 90 CONNECTOR LOCA TIONS XJ DESCRIPTION AND OPERATION Continued...
Page 993: ......
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Page 1034: ...Oil Lubrication System 2 5L Engine XJ 2 5L ENGINE 9 17 DESCRIPTION AND OPERATION Continued...
Page 1075: ...Oil Lubrication System 4 0L Engine 9 58 4 0L ENGINE XJ DESCRIPTION AND OPERATION Continued...
Page 1116: ...XJ ENGINE 9 3 DIAGNOSIS AND TESTING Continued...
Page 1117: ...9 4 ENGINE XJ DIAGNOSIS AND TESTING Continued...
Page 1118: ...XJ ENGINE 9 5 DIAGNOSIS AND TESTING Continued...
Page 1119: ...9 6 ENGINE XJ DIAGNOSIS AND TESTING Continued...
Page 1120: ...XJ ENGINE 9 7 DIAGNOSIS AND TESTING Continued...
Page 1121: ...9 8 ENGINE XJ DIAGNOSIS AND TESTING Continued...
Page 1122: ...XJ ENGINE 9 9 DIAGNOSIS AND TESTING Continued...
Page 1123: ...9 10 ENGINE XJ DIAGNOSIS AND TESTING Continued...
Page 1124: ...XJ ENGINE 9 11 DIAGNOSIS AND TESTING Continued...
Page 1159: ...SPECIFICATIONS ENGINE SPECIFICA TIONS 9 46 ENGINE XJ...
Page 1160: ...XJ ENGINE 9 47 SPECIFICATIONS Continued...
Page 1171: ......
Page 1188: ...Fig 6 Frame Dimensions XJ FRAME AND BUMPERS 13 7 SPECIFICATIONS Continued...
Page 1281: ......
Page 1293: ...Fig 1 Recirculating Ball Type Gear 19 12 STEERING XJ DESCRIPTION AND OPERATION Continued...
Page 1307: ...SPECIAL TOOLS STEERING LINKAGE Puller C 3894 A Remover Pitman C 4150A 19 26 STEERING XJ...
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Page 1504: ...DIAGNOSIS TABLE XJ TRANSMISSION AND TRANSFER CASE 21 181 DIAGNOSIS AND TESTING Continued...
Page 1600: ...A W 4 TORQUE SPECIFICA TIONS XJ TRANSMISSION AND TRANSFER CASE 21 277 SPECIFICATIONS Continued...
Page 1702: ...Fig 3 Hood Components XJ BODY 23 21 REMOVAL AND INSTALLATION Continued...
Page 1740: ...WELD LOCA TIONS UPPER COWL XJ BODY 23 59 SPECIFICATIONS Continued...
Page 1741: ...UPPER COWL 23 60 BODY XJ SPECIFICATIONS Continued...
Page 1742: ...COWL XJ BODY 23 61 SPECIFICATIONS Continued...
Page 1743: ...A PILLAR 23 62 BODY XJ SPECIFICATIONS Continued...
Page 1744: ...A PILLAR XJ BODY 23 63 SPECIFICATIONS Continued...
Page 1745: ...A PILLAR 23 64 BODY XJ SPECIFICATIONS Continued...
Page 1746: ...A PILLAR XJ BODY 23 65 SPECIFICATIONS Continued...
Page 1747: ...B PILLAR 23 66 BODY XJ SPECIFICATIONS Continued...
Page 1748: ...D PILLAR XJ BODY 23 67 SPECIFICATIONS Continued...
Page 1749: ...FUEL FILLER OPENING 23 68 BODY XJ SPECIFICATIONS Continued...
Page 1750: ...CARGO AREA FLOOR PAN XJ BODY 23 69 SPECIFICATIONS Continued...
Page 1751: ...ROOF AND D PILLAR 23 70 BODY XJ SPECIFICATIONS Continued...
Page 1752: ...LIFTGA TE OPENING XJ BODY 23 71 SPECIFICATIONS Continued...
Page 1753: ...ROOF 23 72 BODY XJ SPECIFICATIONS Continued...
Page 1754: ...ROOF XJ BODY 23 73 SPECIFICATIONS Continued...
Page 1755: ...FRAME RAIL 23 74 BODY XJ SPECIFICATIONS Continued...
Page 1756: ...FRAME RAIL XJ BODY 23 75 SPECIFICATIONS Continued...
Page 1757: ...FRAME RAIL 23 76 BODY XJ SPECIFICATIONS Continued...
Page 1758: ...FRAME RAIL XJ BODY 23 77 SPECIFICATIONS Continued...
Page 1759: ...REINFORCEMENT 23 78 BODY XJ SPECIFICATIONS Continued...
Page 1760: ...FRONT INNER FENDER XJ BODY 23 79 SPECIFICATIONS Continued...
Page 1761: ...FRONT INNER FENDER AND RADIA TOR CLOSURE PANEL 23 80 BODY XJ SPECIFICATIONS Continued...
Page 1762: ...REINFORCEMENT FRONT FENDER XJ BODY 23 81 SPECIFICATIONS Continued...
Page 1763: ...BODY SIDE 23 82 BODY XJ SPECIFICATIONS Continued...
Page 1764: ...REAR WHEELHOUSE XJ BODY 23 83 SPECIFICATIONS Continued...
Page 1765: ...REAR INNER WHEELHOUSE 23 84 BODY XJ SPECIFICATIONS Continued...
Page 1766: ...BODY SIDE XJ BODY 23 85 SPECIFICATIONS Continued...
Page 1767: ...BODY SIDE 23 86 BODY XJ SPECIFICATIONS Continued...
Page 1768: ...BODY SIDE XJ BODY 23 87 SPECIFICATIONS Continued...
Page 1769: ...BODY SIDE 23 88 BODY XJ SPECIFICATIONS Continued...
Page 1770: ...BODY SIDE XJ BODY 23 89 SPECIFICATIONS Continued...
Page 1771: ...BODY SIDE 23 90 BODY XJ SPECIFICATIONS Continued...
Page 1772: ...UNDERBODY XJ BODY 23 91 SPECIFICATIONS Continued...
Page 1773: ...UNDERBODY 23 92 BODY XJ SPECIFICATIONS Continued...
Page 1774: ...UNDERBODY XJ BODY 23 93 SPECIFICATIONS Continued...
Page 1775: ...UNDERBODY 23 94 BODY XJ SPECIFICATIONS Continued...
Page 1776: ...UNDERBODY XJ BODY 23 95 SPECIFICATIONS Continued...
Page 1777: ...UNDERBODY 23 96 BODY XJ SPECIFICATIONS Continued...
Page 1778: ...UNDERBODY XJ BODY 23 97 SPECIFICATIONS Continued...
Page 1779: ...UNDERBODY 23 98 BODY XJ SPECIFICATIONS Continued...
Page 1780: ...UNDERBODY XJ BODY 23 99 SPECIFICATIONS Continued...
Page 1781: ...UNDERBODY 23 100 BODY XJ SPECIFICATIONS Continued...
Page 1782: ...UNDERBODY XJ BODY 23 101 SPECIFICATIONS Continued...
Page 1783: ...BODY SEALING LOCA TIONS APPLICA TION METHODS 23 102 BODY XJ SPECIFICATIONS Continued...
Page 1784: ...COWL AND DASH PANEL XJ BODY 23 103 SPECIFICATIONS Continued...
Page 1785: ...DASH PANEL AND FLOOR PAN 23 104 BODY XJ SPECIFICATIONS Continued...
Page 1786: ...FLOOR PAN XJ BODY 23 105 SPECIFICATIONS Continued...
Page 1787: ...REAR INNER WHEELHOUSE 23 106 BODY XJ SPECIFICATIONS Continued...
Page 1788: ...FRONT INNER WHEELHOUSE XJ BODY 23 107 SPECIFICATIONS Continued...
Page 1789: ...BODY SIDE 23 108 BODY XJ SPECIFICATIONS Continued...
Page 1790: ...BODY SIDE XJ BODY 23 109 SPECIFICATIONS Continued...
Page 1791: ...BODY SIDE 23 110 BODY XJ SPECIFICATIONS Continued...
Page 1792: ...ROOF PANEL XJ BODY 23 111 SPECIFICATIONS Continued...
Page 1793: ...FUEL FILLER HOUSING 23 112 BODY XJ SPECIFICATIONS Continued...
Page 1794: ...LIFTGA TE OPENING XJ BODY 23 113 SPECIFICATIONS Continued...
Page 1795: ...STRUCTURAL ADHESIVE LOCA TIONS LEFT QUARTER PANEL 23 114 BODY XJ SPECIFICATIONS Continued...
Page 1796: ...REAR WHEELHOUSE XJ BODY 23 115 SPECIFICATIONS Continued...
Page 1797: ...ROOF BOWS 23 116 BODY XJ SPECIFICATIONS Continued...
Page 1798: ...BODY GAP AND FLUSH MEASUREMENTS XJ BODY 23 117 SPECIFICATIONS Continued...
Page 1805: ...ENGINE COMPARTMENT 23 124 BODY XJ SPECIFICATIONS Continued...
Page 1807: ...SPECIAL TOOLS BODY Remover Moldings C 4829 23 126 BODY XJ...
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Page 1940: ...FASTENER IDENTIFICATION XJ INTRODUCTION 5 GENERAL INFORMATION Continued...
Page 1941: ...FASTENER STRENGTH 6 INTRODUCTION XJ GENERAL INFORMATION Continued...
Page 1943: ...METRIC CONVERSION 8 INTRODUCTION XJ GENERAL INFORMATION Continued...
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