Jeep Cherokee 1999 Electronic Service Manual page 1233

14 - 42 FUEL SYSTEM
DI AGN OSI S AN D T EST I N G (Cont inue d)
Fig. 36 Engine Coolant Temperature Sensor—
SEN SOR RESI STAN CE (OH M S)—COOLAN T
T EM PERAT U RE SEN SOR/I N TAK E AI R
T EM PERAT U RE SEN SOR
TEMPERATURE
°CEL. °FAHR.
-40 -40
-20 -4
-10 14
0 32
10 50
20 68
25 77
30 86
40 104
50 122
60 140
70 158
80 176
90 194
100 212
110 230
120 248
Typical
RESISTANCE (OHMS)
MIN. MAX.
291,490 381,710
85,850 108,390
49,250 61,430
29,330 35,990
17,990 21,810
11,370 13,610
9,120 10,880
7,370 8,750
4,900 5,750
3,330 3,880
2,310 2,670
1,630 1,870
1,170 1,340
860 970
640 720
480 540
370 410
IDLE AIR CONTROL (IAC) MOTOR
To per for m a com plet e t est of t h e IAC m ot or a n d
it s cir cu it r y, r efer t o DRB sca n t ool a n d a ppr opr ia t e
P ower t r a in Dia gn ost ics P r ocedu r es m a n u a l.
INTAKE MANIFOLD AIR TEMPERA TURE
SENSOR
To per for m a com plet e t est of t h e in t a ke m a n ifold
a ir t em per a t u r e sen sor a n d it s cir cu it r y, r efer t o DRB
t est er a n d a ppr opr ia t e P ower t r a in Dia gn ost ics P r oce-
du r es m a n u a l. To t est t h e sen sor on ly, r efer t o t h e
followin g:
(1) Discon n ect wir e h a r n ess con n ect or fr om in t a ke
m a n ifold a ir t em per a t u r e sen sor (F ig. 37) or (F ig.
38).
Fig. 37 Intake Manifold Air Temperature Sensor—
4.0L Engine
(2) Test t h e r esist a n ce of sen sor wit h a h igh in pu t
im peda n ce (digit a l) volt -oh m m et er. Refer t o SE NSOR
RE SISTANCE (OH MS)—COOLANT
TURE SE NSOR/INTAKE
SE NSOR ch a r t . Th e r esist a n ce (a s m ea su r ed a cr oss
sen sor t er m in a ls) sh ou ld be wit h in r a n ge sh own in
ch a r t . If n ot , r epla ce sen sor.
(3) Test r esist a n ce
bet ween P CM wir e h a r n ess con n ect or A-15 a n d sen -
sor con n ect or t er m in a l. Also ch eck bet ween P CM con -
n ect or A-4 t o sen sor con n ect or t er m in a l. Repa ir wir e
h a r n ess a s n ecessa r y if r esist a n ce is gr ea t er t h a n 1
oh m .
POWER STEERING PRESSURE SWITCH
2.5L 4–Cylinder Engine Only
Th is swit ch (F ig. 39) pr ovides a n in pu t t o t h e P ow-
er t r a in Con t r ol Modu le (P CM). Th e in pu t is pr ovided
TE MP E RA-
AIR TE MP E RATURE
of wir e h a r n ess. Do t h is
X J