1988 JEEP CHEROKEE check engine

Model 228 ............................................ 7.0 pts. (3.3L)\
Model 229 ............................................ 6.0 pts. (3.8L)\









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DRAINING & REFILLING
Transmission
1) Loosen oil pan bolts, tap pan to break it loose and allow
fluid to drain. Remove pan. Install new filter on bottom of valve
body and tighten retaining screws. Install new "O" ring on fluid
pick-up pipe (if needed). Clean oil pan and install with new gasket.
2) Refill transmission with fluid. Start engine and allow to
run at curb idle for a few minutes. With vehicle on level surface,
engine idling and parking brake applied, move shift selector lever
through all gear ranges, ending in "N" ("P" for AW-4 transmission).
Add fluid up to "ADD ONE PINT" mark on dipstick.
3) Recheck fluid level when transmission reaches normal
operating temperature. Fluid should be between "ADD ONE PINT" and
"FULL" marks on dipstick. Transmission must NOT be overfilled.
Transfer Case
Remove drain plug from transfer case. Remove fill plug for
easier draining. With fluid fully drained, reinstall drain plug. Fill
transfer case to fill plug opening with Dexron II.
ADJUSTMENT
NOTE: Bands on the AW-4 (4-speed overdrive) transmission are not
adjustable. If slippage occurs, bands must be replaced.
KICKDOWN (FRONT) BAND
1) Locate kickdown band adjusting screw on left side of case
(near throttle lever shaft). Loosen adjusting screw lock nut and back
off approximately 5 turns. Ensure adjusting screw turns freely in
case.
2) Using Adapter (J-24063) and 5/16" square socket, tighten
screw to 36 INCH lbs. (4 N.m). If adapter is not used, tighten screw
to 72 INCH lbs. (8 N.m). Back off adjusting screw. See KICKDOWN
(FRONT) BAND ADJUSTMENT table. Hold adjusting screw in position and
tighten lock nut to 35 ft. lbs. (48 N.m).
KICKDOWN (FRONT) BAND ADJUSTMENT









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Application (1) Back Off Screw\
All Models ............................................... 2 1/2 Turns
(1) - Tighten screw to 72 INCH lbs. (8 N.m) and back off indicated
number of turns.









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LOW-REVERSE (REAR) BAND
1) Raise vehicle, drain transmission fluid and remove oil
pan. Locate adjusting screw on rear servo lever. Loosen adjusting
screw lock nut and back off about 5 turns.
2) Tighten screw to 41 INCH lbs. (4.6 N.m) and back off
screw at indicated number of turns. See LOW-REVERSE (REAR) BAND
ADJUSTMENT table. Hold adjusting screw in position and tighten lock
nut to 35 ft. lbs. (48 N.m). Install oil pan and fill transmission

3) Loosen bolt on throttle control link. Pull on link end to
eliminate lash. Tighten adjusting bolt. Press extend button on
Exerciser Box. When ISA retracts, release button and disconnect
Exerciser Box. Connect ISA wiring and remove spring from throttle
control lever. Install and reconnect any parts removed and/or
disconnected.
999 Transmission with 6-Cylinder Engines
1) Disconnect throttle control rod spring. Use spring to
hold adjusting link in forward position, against nylon washer. Block
choke open and release fast idle cam.
2) Raise vehicle. Loosen both retaining bolts on adjusting
link clamp. DO NOT remove spring clip or nylon washer. Use a spare
spring to hold transmission throttle lever against forward stop.
3) Push adjusting link to eliminate lash and pull clamp to
rear so that bolt in rod bottoms in rear of slot in rod. Tighten
forward clamp retaining bolt.
4) Pull throttle control rod to the rear so that bolt in
rod bottoms in front of slot and tighten rear retaining bolt. Remove
spare spring. Lower vehicle and reconnect throttle control rod spring.
AW-4 Transmission with All Engines
1) With ignition off, retract cable self-adjusting mechanism
fully. Press cable button down and push cable plunger inward.
2) Rotate throttle lever to wide open throttle position.
While holding throttle lever in position, allow cable plunger to
extend. When plunger is fully extended, release throttle lever. Cable
is now adjusted.
SHIFT LINKAGE
Cable Linkage
1) Place gearshift lever in "P" position and raise vehicle.
Using a small screwdriver, unlock shift control cable by releasing
U-shaped cable adjuster clamp. Remove cable from mounting bracket.
2) Move transmission shift lever rearward until fully
seated into "P" detent. Ensure that driveshaft cannot be rotated.
Snap control cable into cable mounting bracket and replace U-shaped
cable adjuster clamp.
3) Lower vehicle and verify engine starting. Engine should
start only with shifter in "P" or "N" position.
Rod Linkage
1) Loosen shift rod trunnion jam nuts at transmission lever.
Remove shift rod-to-bellcrank lock pin. Disengage trunnion and shift
rod. Place selector lever in "P" position and lock steering column.
Move transmission shift lever to full rear Park position.
2) Adjust shift rod trunnion to obtain free pin fit in
bellcrank arm. Tighten jam nuts. On vehicles with shift lever on
column, make sure linkage lash is eliminated by pulling down on shift
rod and pushing up on outer bellcrank when tightening jam nuts.
3) Check steering column lock for ease of operation. Ensure
engine starts in "N" or "P", only. If starter engages in any drive
gear, or does not work in "N" or "P", check for proper shift linkage
adjustment or faulty neutral safety switch.
NEUTRAL SAFETY SWITCH
1) Switch combines functions of neutral safety switch and
back-up light switch. With transmission linkage properly adjusted,
switch should allow starter operation in "P" and "N" only.
2) To test switch, remove wire connector and test for
continuity between center pin of switch and case. Continuity should

\003
TR O UBLE S H O OTIN G - B ASIC P R O CED URES

1988 J e ep C hero ke e
GENERAL TROUBLE SHOOTING
* PLEASE READ THIS FIRST *
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.
ACCESSORIES & ELECTRICAL
CHARGING 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.
BASIC CHARGING SYSTEM TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Vehicle Will Not Dead battery Check battery cells,
Start alternator belt
tension and alternator
output
Loose or corroded battery Check all charging
connections system connections
Ignition circuit or switch Check and replace as
malfunction necessary









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Alternator Light Loose or worn alternator Check alternator drive
Stays On With drive belt tension and
Engine Running condition, See Belt
Adjustment in TUNE-UP
article in the
TUNE-UP section
Loose alternator wiring Check all charging
connections system connections
Short in alternator light See Indicator Warning
wiring Lights in STANDARD
INSTRUMENTS in the
ACCESSORIES &
EQUIPMENT section
Defective alternator stator See Bench Tests in
or diodes ALTERNATOR article
Defective regulator See Regulator Check in

 widening the gap to 1/4-3/8".

Disconnect spark plug wire 

and insert test plug. Ground 

plug, crank engine, and 

check for spark. 










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GOOD SPARK   NO SPARK 









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* If plug sparks, driveability   * Remove coil wire from the 

problem is most likely NOT   distributor and attach the 

in the ignition system.   modified spark plug. Ground 










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 the plug and crank engine 
 while checking for spark. 









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GOOD SPARK   NO SPARK 









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* If plug has a good spark,   * Proceed to the IGNITION 

the problem is in the plug   PRIMARY TROUBLE SHOOTING 

wires, distributor cap, or   CHECK CHART below in this 

rotor. Replace components   article. 

as necessary.  









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Ignition Primary Trouble Shooting Chart








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START: Visually inspect primary ignition wires for 

broken, frayed, split, or cut wires. Also check 

for loose, corroded, or disconnected connectors. 










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OK   NOT OK 




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* Check that battery voltage   * Repair or replace damaged 

is at least 11.5 volts.   components as necessary. 










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NOT OK   OK 








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* Replace or recharge the   * Check for battery voltage 

battery.   at the positive terminal of 










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 the coil. 









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OK   NOT OK 




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* Check air Gap of the Pick-Up   * Check resistance of ballast 

coil in the distributor.   resistor (if used) for the 










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 correct resistance value. 
 








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 OK   NOT OK  




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* Check Pick-Up coil for   * Adjust or replace as  

correct resistance value.   necessary.  










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NOT OK   OK  








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* Replace Pick-Up coil if   * Check control module for  

not to specification.   good ground connections.  










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OK  




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* If vehicle fails to run at this point, go to  
 the appropriate article in the ENGINE  
 PERFORMANCE section.  









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OK   NOT OK 




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* Check wires from the battery/  * Replace ballast resistor 

ignition switch to the coil.   if the measured resistance 

Also check the coil primary   value is not within 

and secondary resistance.   specification. 










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STARTER 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.
BASIC STARTER TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Starter Fails Dead battery or bad Check battery charge
to Operate connections between and all wires and
starter and battery connections to starter
Ignition switch faulty Adjust or replace
or misadjusted ignition switch
Open circuit between Check and repair wires
starter switch ignition and connections as
terminal on starter relay necessary
Starter relay or starter See Testing in STARTER
defective article

Open solenoid pull-in See Testing in STARTER
wire article









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Starter Does Not Weak battery or dead Charge or replace
Operate and cell battery as necessary
Headlights Dim
Loose or corroded battery Check that battery
connections connections are clean
and tight
Internal ground in See Testing in STARTER
starter windings article
Grounded starter fields See Testing in STARTERS
Armature rubbing on pole See STARTER article
shoes









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Starter Turns Starter clutch slipping See STARTER article
but Engine
Does Not Rotate
Broken clutch housing See STARTER article
Pinion shaft rusted or See STARTER article
dry
Engine basic timing See Ignition Timing in
incorrect TUNE-UP article
Broken teeth on engine Replace flywheel and
flywheel check for starter pinion
gear damage









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Starter Will Not Faulty overrunning See STARTER article
Crank Engine clutch
Broken clutch housing See STARTER article
Broken flywheel teeth Replace flywheel and
check for starter pinion
gear damage
Armature shaft sheared See STARTER article
or reduction gear teeth
stripped
Weak battery Charge or replace
battery as necessary
Faulty solenoid See On-Vehicle Tests in
STARTER article
Poor grounds Check all ground
connections for
tight and clean
connections
Ignition switch faulty Adjust or replace
or misadjusted ignition switch as
necessary









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Starter Cranks Battery weak or Charge or replace
Engine Slowly defective battery as necessary

Engine overheated See ENGINE COOLING
SYSTEM article
Engine oil too heavy Check that proper
viscosity oil
is used
Poor battery-to-starter Check that all
connections between
battery and starter are
clean and tight
Current draw too low or See Bench Tests in
too high STARTER article
Bent armature, loose pole See STARTER article
shoes screws or worn
bearings
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter









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Starter Engages Engine timing too far See Ignition Timing in
Engine Only advanced TUNE-UP article
Momentarily
Overrunning clutch not Replace overrunning
engaging properly clutch. See STARTER
article
Broken starter clutch See STARTER article
Broken teeth on engine Replace flywheel and
flywheel check starter pinion
gear for damage
Weak drive assembly See STARTER article
thrust spring
Weak hold-in coil See Bench Tests in
STARTER article









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Starter Drive Defective point assembly See Testing in STARTER
Will Not Engage article
Poor point assembly ground See Testing in STARTER
article
Defective pull-in coil Replace starter
solenoid









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Starter Relay Dead battery Charge or replace
Does Not Close battery as necessary
Faulty wiring Check all wiring and
connections leading to
relay
Neutral safety switch Replace neutral safety
faulty switch
Starter relay faulty Replace starter relay

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Starter Drive Starter motor loose on Tighten starter
Will Not mountings attach bolts
Disengage
Worn drive end bushing See STARTER article
Damaged engine flywheel Replace flywheel and
teeth starter pinion gear for
damage
Drive yolk return spring Replace return spring
broken or missing
Faulty ignition switch Replace ignition switch
Insufficient clearance Replace starter
between winding leads to solenoid
solenoid terminal and main
contact in solenoid
Starter clutch not Replace starter clutch
disengaging
Ignition starter switch Replace ignition switch
contacts sticking









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Starter Relay Faulty solenoid switch, Check all wiring
Operates but switch connections or between relay and
Solenoid Does Not solenoid or replace
relay or solenoid as
necessary
Broken lead or loose Repair wire or wire
soldered connections connections as
necessary









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Solenoid Plunger Weak battery Charge or replace
Vibrates When battery as necessary
Switch is Engaged
Solenoid contacts Clean contacts or
corroded replace solenoid
Faulty wiring Check all wiring
leading to solenoid
Broken connections inside Repair connections or
switch cover replace solenoid
Open hold-in wire Replace solenoid









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Low Current Draw Worn brushes or weak Replace brushes or
brush springs as
necessary









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High Pitched Whine Distance too great Align starter or check
During Cranking between starter that correct starter
Before Engine pinion and flywheel and flywheel are being
Fires but Engine used
Fires and Cranks
Normally









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High Pitched Distance too small between
Whine After Engine starter pinion and flywheel