sensor JEEP CHEROKEE 1988 Service Repair Manual
Page 1138 of 1378
threads damaged ........ A ... Require repair or replacement
of part with damaged threads.
Attaching hardware
threads stripped
(threads missing) ...... A ..... Require replacement of part
with stripped threads.
Dust boot missing ....... 2 ........ (1) Suggest replacement.
Dust boot split ......... 2 ........ ( 1) Suggest replacement.
Dust boot torn .......... 2 ........ ( 1) Suggest replacement.
Housing cracked ......... A ............ Require replacement.
Lead routing incorrect .. B .. Require rerouting according to
vehicle manufacturer's
specifications.
Loose ................... B ... Require adjustment to vehicle
manufacturer's specifications.
Missing ................. C ............ Require replacement.
Output signal incorrect . A .. Require repair or replacement.
Wire lead damaged ....... A .. Require repair or replacement.
( 1) - This condition can lead to damage of the sliding magnet,
which, in turn, causes premature sensor failure.
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AIR RIDE SUSPENSION - MODULES
AIR RIDE SUSPENSION - MODULE INSPECTION \
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Condition Code Procedure
Attaching hardware
loose .................. A ... Require repair or replacement
of loose part.
Attaching hardware
missing ................ C .. Require replacement of missing
part.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of part with damaged threads.
Attaching hardware
threads stripped
(threads missing) ...... A ..... Require replacement of part
with stripped threads.
Housing cracked ......... 2 .. Suggest repair or replacement.
Inoperative ............. A ............ Require replacement.
Missing ................. C ............ Require replacement.
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AIR RIDE SUSPENSION - RELAYS (COMPRESSOR)
AIR RIDE SUSPENSION - RELAY (COMPRESSOR) INSPECTION \
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Condition Code Procedure
Housing cracked ......... 2 ........ ( 1) Suggest replacement.
Intermittent ............ A ............ Require replacement.
Missing ................. C ............ Require replacement.
Output signal incorrect . A ............ Require replacement.
( 1) - If moisture enters the relay, it can reduce life
expectancy or impair function.
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AIR RIDE SUSPENSION - SWITCHES (ON/OFF)
Page 1199 of 1378
Will Not Shift Or Difficult To Shift Into Gear
Vehicle speed too high; slow vehicle to 2-3 MPH to shift.
Vehicle operated too long on dry paved surface; stop vehicle and place
in Reverse or Neutral to relieve driveline torque. Ensure transfer
case external linkage is not binding. Ensure correct fluid is used.
Internal parts may be worn or damaged.
Noisy In All Gears
Check fluid level. Ensure correct fluid is used. If fluid is
okay, locate possible internal mechanical problem.
Jumps Out Of Gear Or Noisy In 4WD
Transfer case not completely in gear; check shift linkage.
Range fork damaged. Shift fork pads are worn or shift fork binding.
Low range gear worn.
Fluid Leaking From Vent Or Seals
Transfer case overfilled. Vent plugged. Output shaft seals
are damaged or not installed properly.
ON-VEHICLE SERVICE
FRONT OIL SEAL
Removal & Installation
1) Mark front drive shaft and flange for installation
alignment reference. Remove front drive shaft. Remove flange. Discard
washer and nut. Using a screwdriver, carefully remove oil seal. Ensure
seal contact surface is clean.
2) Apply ATF to seal lip and flange seal surface. Install NEW
oil seal. Install flange and NEW washer and nut. Tighten nut to
specifications. See TORQUE SPECIFICATIONS . Install front drive shaft
using alignment marks. Check transfer case fluid.
EXTENSION HOUSING OIL SEAL & BUSHING
Removal & Installation
1) Mark rear drive shaft and flange for installation
alignment reference. Remove rear drive shaft. Tap extension housing in
a clockwise direction and remove extension housing. DO NOT pry on
extension housing. Using a screwdriver, remove oil seal from extension
housing.
2) Using bushing driver, replace bushing in extension
housing. Install NEW extension housing oil seal. Apply silicone
sealant to extension housing mating surface. Install extension
housing. To complete installation, reverse removal procedure.
REMOVAL & INSTALLATION
TRANSFER CASE
Removal
1) Shift transfer case into 4H and disconnect battery
negative cable. Raise vehicle, remove skid plate and drain fluid.
2) Mark front and rear output shaft yokes to drive shafts for
reassembly reference. Support transfer case and remove rear
crossmember. Remove drive shafts.
3) Disconnect vehicle speed sensor electrical connector and
vacuum (hoses) harness at transfer case. Remove shift lever or linkage\
rod from case. Remove transfer case attaching bolts. Remove transfer
case from vehicle.
Page 1200 of 1378
Installation
1) Clean all old gasket material from transmission and
transfer case mating surfaces. Position NEW gasket on transfer case
with orientation tab at upper left bolt hole.
2) Install transfer case, aligning splines of input shaft
with transmission. Slide transfer case forward until seated against
transmission. Install transfer case attaching bolts and tighten to
specification. See TORQUE SPECIFICATIONS . Install rear crossmember.
3) Attach shift lever and connect speed sensor electrical
connector and vacuum harness at transfer case. Using reference marks
made during removal, reinstall front and rear drive shafts. Refill
transfer case. Install skid plate and lower vehicle. Connect negative
battery cable. Road test vehicle.
TRANSFER CASE DISASSEMBLY
1) Remove front companion yoke. See Fig. 2 or 3. Discard
washer and nut. Shift transfer case to 4L and remove extension
housing. Remove rear bearing snap ring. Using 2 screwdrivers under
each tab, remove retainer housing. Remove rear case and oil pump as an
assembly.
2) Remove oil pump pick-up screen and tube from rear case.
Remove oil pump. Remove "O" ring from oil pump and discard. DO NOT
separate oil pump halves. Pump must be replaced as an assembly if
necessary.
3) Remove mode spring. Using a soft hammer, tap front output
shaft upward and remove with drive chain as an assembly. Remove
mainshaft, mode fork and shift rail as an assembly. Remove mode fork
and shift rail from synchronizer sleeve.
4) Mark synchronizer sleeve position for reassembly
reference. Remove synchronizer sleeve from mainshaft. Remove
synchronizer hub snap ring. Remove synchronizer hub, stop ring and
drive sprocket. Slide range fork pin out of sector.
5) Remove range fork and shift hub as an assembly. Remove
range lever from sector shaft. Remove shift sector, bushing and "O"
ring. Remove shift detent pin, spring and plug. Remove front bearing
retainer. Remove input gear snap ring.
6) Press input and low range gear assembly from input gear
bearing. Remove low range gear snap ring. Remove input gear retainer,
thrust washers and input gear from low range gear.
7) Remove all oil seals. Remove magnet from front case.
Remove front bearing snap ring. Using a plastic hammer, remove front
bearing. Press input gear bearing from front case.
8) Using slide hammer and internal puller, remove input gear
pilot bearing. Press bearings from drive sprocket. Using internal
puller and slide hammer, remove output shaft rear bearing.
Page 1205 of 1378
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Application Ft. Lbs. (N.m)
Companion Flange Nut
Chrysler Corp. ....................... 130-200 (176-271)
General Motors ................................ 80 (108)
Jeep ......................................... 110 (149)
Detent Plug
General Motors ................................. 11 (15)
Chrysler Corp. & Jeep .......................... 15 (20)
Drain & Fill Plug .......................... 30-40 (41-54)
Extension Housing Bolt ..................... 20-25 (27-34)
Front Bearing Retainer Bolt
Chrysler Corp. & Jeep .......................... 16 (22)
General Motors ................................. 14 (19)
Front Case-to-Rear Case Bolt
Chrysler Corp.
Flange Head Bolt ........................ 35-45 (47-61)
All Other Bolts ........................ 20-25 (27-34)
General Motors ................................. 23 (31)
Jeep ..................................... 20-25 (27-34)
Range Lever Nut ............................ 15-20 (20-27)
Rear Bearing Retainer Bolt ................. 20-25 (27-34)
Rear Crossmember ................................. 30 (41)
Shift Lever Lock Bolt ............................ 10 (14)
Speed Sensor Bolt ................................ 23 (31)
Transfer Case-to-Transmission Nut ................ 26 (35)
Vacuum Switch
Chrysler Corp. ........................... 15-25 (20-34)
General Motors ................................. 17 (23)
Jeep ..................................... 20-25 (27-34)
INCH Lbs.
Control Cable Lock Nut ............................ 18 (2)
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VACUUM DIAGRAMS
For vacuum diagrams, refer to appropriate VACUUM DIAGRAMS
article in the ENGINE PERFORMANCE section.
Page 1247 of 1378
Low fuel pressure Test pressure regul-
ator and fuel pump,
check for restricted
lines and filters
No distributor reference Repair ignition
pulses system as necessary
Open coolant temperature Test sensor and
sensor circuit wiring
Shorted W.O.T. switch in Disconnect W.O.T.
T.P.S. switch, engine
should start
Defective ECM Replace ECM
Fuel tank residual pressure Test for fuel
valve leaks pressure drop after
shut down
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Hard Starting Disconnected hot air tube Reconnect tube and
to air cleaner test control valve
Defective Idle Air Control Test valve operation
(IAC) valve and circuit
Shorted, open or misadjusted Test and adjust or
T.P.S. replace T.P.S.
EGR valve open Test EGR valve and
control circuit
Poor Oxygen sensor signal Test for shorted or
circuit
Incorrect mixture from PCV Test PCV for flow,
system check sealing of oil
filter cap
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Poor High Speed Low fuel pump volume Faulty pump or
Operation restricted fuel
lines or filters
Poor MAP sensor signal Test MAP sensor,
vacuum hose and
wiring
Poor Oxygen sensor signal Test for shorted or
open sensor or
circuit
Open coolant temperature Test sensor and
sensor circuit wiring
Faulty ignition operation Check wires for
cracks or poor con-
nections, test
secondary voltage
with oscilloscope
Contaminated fuel Test fuel for water
Page 1248 of 1378
or alcohol
Intermittent ECM ground Test ECM ground
connection for
resistance
Restricted air cleaner Replace air cleaner
Restricted exhaust system Test for exhaust
manifold back
pressure
Poor MAF sensor signal Check leakage
between sensor and
manifold
Poor VSS signal If tester for ALCL
hook-up is available
check that VSS
reading matches
speedometer
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Ping or Knock on Poor Knock sensor signal Test for shorted or
Acceleration open sensor or
circuit
Poor Baro sensor signal Test for shorted or
open sensor or
circuit
Improper ignition timing See VEHICLE EMISSION
CONTROL LABEL (where
applicable)
Check for engine Low coolant, loose
overheating problems belts or electric
cooling fan
inoperative
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NOTE: For additional electronic fuel injection trouble shooting
information, see the appropriate article in the ENGINE
PERFORMANCE section (not all vehicles have Computer Engine
Control articles). Information is provided there for
diagnosing fuel system problems on vehicles with electronic
fuel injection.
IGNITION SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
Ignition Secondary Trouble Shooting Chart
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START: Visually inspect Spark Plug Wires, Coil Wires,
Plug Wire Boots, Rotor, and Distributor Cap for
signs of damage.
Page 1286 of 1378
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Application Champion No.
2.5L ...................................................... RC-12LYC
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SPARK PLUG SPECIFICATIONS \
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Application Gap: In. (mm) Torque: Ft. Lbs. (N.m\
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2.5L .................. .035 (.89) ................... 7-15 (9-20\
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HIGH TENSION WIRE RESISTANCE
Do not puncture spark plug wires with any type of probe.
Remove spark plug wire and check resistance with an ohmmeter.
ADJUSTMENTS
VALVE ARRANGEMENT
* E-I-I-E-E-I-I-E (Front-to-rear).
VALVE CLEARANCE
All models are equipped with hydraulic lifters, which should
be adjusted to zero lash.
IGNITION COIL WIRE
Remove ignition coil wire from coil and distributor cap.
Check terminals for corrosion and clean if necessary. Check coil wire
resistance. Replace wire if resistance is excessive.
HIGH TENSION WIRE RESISTANCE (OHMS)
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Wire Length (In.) Minimum Maximum\
0-15 ........................ 3000 ........................ 10,000
15-25 ....................... 4000 ........................ 15,000
25-35 ....................... 6000 ........................ 20,000
Over 35 ..................... 8000 ........................ 25,000
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DISTRIBUTOR
All models are equipped with a Renix solid state ignition
module. Renix system uses a TDC sensor mounted near the flywheel. The
distributor consists of a cap and rotor. Its only function is to
distribute high voltage to appropriate spark plug. No adjustments are
required on either system.
Page 1289 of 1378
Fig. 3: TBI Idle Speed Control (ISC) Motor Adjustment
Courtesy of Chrysler Motors.
4) Connect ISC motor connector. Turn ignition off for 10
seconds. ISC motor should fully extend. Restart engine. Engine speed
should momentarily be about 3500 RPM and return to idle speed. Turn
ignition off and disconnect tachometer. Apply sealant to adjustment
screw threads. Install air cleaner.
IDLE SPEED (RPM)
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Application Curb Idle
2.5L TBI (ISC Plunger Extended) ............................... 3500\
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NOTE: Holding plunger inward may create an intermittent trouble
code in ECU memory. To clear ECU memory, turn ignition off
and disconnect negative battery cable for 10 seconds.
THROTTLE POSITION SENSOR (TPS) ADJUSTMENT
NOTE: On some models, it may be necessary to remove throttle body
from intake manifold, to access sensor wiring harness.
Automatic Transmission
1) Locate the square TPS connector. Note connector terminal
identification stamped on the back of the connector. Turn ignition on.
2) Connect voltmeter through back of wiring harness
Page 1290 of 1378
connector. Connect negative voltmeter lead to terminal "D" and
positive voltmeter lead to terminal "A" to check input voltage. DO NOT
disconnect TPS connector.
3) Hold throttle plate closed against idle stop and note
voltage. Input voltage should be approximately 5 volts. Disconnect
voltmeter positive lead and connect to terminal "B" to measure output
voltage.
4) With throttle plate closed, measure the output voltage.
The output voltage should be approximately .2 volts. If output voltage
is not within specification, loosen TPS retaining screws.
5) Partially tighten one retaining screw. Rotate TPS to
obtain correct output voltage. Tighten retaining screws once correct
voltage is obtained.
Manual Transmission
1) Turn ignition on. Connect voltmeter through back of wiring
harness connector. Connect negative voltmeter lead to terminal "B" and
positive voltmeter lead to terminal "C". DO NOT disconnect TPS
connector. See Fig. 4.
2) Rotate and hold throttle plate in wide open position.
Ensure throttle linkage contacts stop. Note voltmeter reading. Voltage
reading should be 5 volts at wide open throttle. Return throttle plate
to closed throttle position. Disconnect voltmeter positive lead from
sensor terminal "C" and connect it to terminal "A".
3) Rotate and hold throttle plate in wide open position.
Ensure throttle linkage contacts stop. Note voltmeter reading. Output
voltage should be 4.6-4.7 volts. If voltage is not as specified,
loosen sensor mounting screw. Loosen upper sensor mounting screw for
small adjustments and lower screw for large adjustments.
4) Adjust sensor. Tighten sensor mounting screws. Remove
voltmeter and return throttle plate to closed position. Replace sensor
if specified output voltage cannot be obtained.
Fig. 4: Adjusting Throttle Position Sensor (Man Trans)
Courtesy of Chrysler Motors.
IDLE MIXTURE ADJUSTMENT
Page 1298 of 1378
wires connected to switch). Disconnect distributor vacuum advance hose
and connect hose to vacuum switch. Disconnect wire connector from
knock sensor, located in cylinder head.
3) Using a jumper wire, ground knock sensor wire connector to
engine block. Start engine. With engine at idle speed (solenoid
energized), check timing. Adjust timing to one degree more than
specification (if required). See Emission Control Label.
IGNITION TIMING SPECIFICATIONS (DEGREES BTDC@RPM) - 4.2L
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Application Man. Trans. Auto. Trans.
50 State ............. 9 @ 1600 ............... 9 @ 1600
High Altitude ........ 16 @ 1600 ............. 16 @ 1600
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HOT (SLOW) IDLE RPM
4.0L
1) Apply parking brake and place transmission in Neutral
(Drive for automatic transmissions). Operate engine to normal
operating temperature. Turn ignition off.
2) Ensure all accessories are off. Connect positive
tachometer lead to terminal "D1-1" and negative lead to "D2-7" of
diagnostic connectors. See Fig. 3. Disconnect air stepper motor
connector and TPS wiring connector. See Fig. 4.
Fig. 3: Diagnostic Connector Terminal Identification
Courtesy of Chrysler Motors.