1988 JEEP CHEROKEE lock

FUEL TANKS
GAS CAPS
GASKETS
GROMMETS (VALVE COVER)
HARMONIC DAMPERS
HEATER CONTROL VALVES
HEATER CORES
HOSE AND TUBE COUPLERS, CONNECTORS AND CLAMPS
HOSE CLAMPS
HOSE CONNECTORS
HOSE COUPLERS
HOSES AND TUBES (FUEL LINES, RADIATOR, VACUUM, BY PASS,
HEATER, RECOVERY TANK AND OIL COOLERS)
HOUSINGS
IDLE AIR CONTROLS
IDLE SPEED CONTROL ACTUATORS
IGNITION BOOTS
IGNITION COIL TOWERS
IGNITION COILS
IGNITION CONTROL MODULES (ICM)
IGNITION SWITCHES
IGNITION TERMINALS
IGNITION WIRES, BOOTS, COIL TOWERS AND TERMINALS (SECONDARY)
IN-TANK FUEL STRAINERS
INERTIA FUEL SHUT-OFF SWITCHES
INTAKE AIR TEMPERATURE SENSORS
INTAKE MANIFOLDS
INTERCOOLERS
KNOCK SENSORS
LIQUID VAPOR SEPARATORS
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSORS
MASS AIR FLOW (MAF) SENSORS
METAL AIR MANIFOLDS AND PIPES
METAL AIR PIPES
MIX CONTROL SOLENOIDS
MOTOR MOUNTS
O-RINGS, GASKETS, SEALS AND SPRING LOCKS
O2 SENSORS
OIL PRESSURE SENDING UNITS
OIL PUMP PICK-UP SCREENS
OIL PUMPS
PARK NEUTRAL POSITION SWITCHES
PCV BREATHER ELEMENTS
PCV ORIFICES
PCV VALVES
PICK-UP ASSEMBLIES (INCLUDES MAGNETIC, HALL EFFECT AND
OPTICAL)
POWER STEERING PRESSURE SENSORS
POWERTRAIN CONTROL MODULES (PCM) AND PROM
POWERTRAIN CONTROL PROM
PRESSURIZED EXPANSION TANK CAPS
RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS
RADIATOR FAN BLADES
RADIATOR FAN CLUTCHES
RADIATORS
ROLL OVER VALVES
SEALING COMPOUNDS
SEALS
SECONDARY AIR INJECTION SYSTEM MANAGEMENT DEVICES
SENSORS AND ACTUATORS
SHROUDS, BAFFLES AND DEFLECTORS
SPARK PLUGS
SPRING LOCKS

Reasons to Suggest Repair or Replacement
1 - Part is close to the end of its useful life (just above
discard specifications, or weak; failure likely to occur
soon, etc.)
2 - To address a customer need, convenience, or request (to
stiffen ride, enhance performance, eliminate noise,
etc.)
3 - To comply with maintenance recommended by the vehicle's
Original Equipment Manufacturer (OEM)
4 - Technician's recommendation based on substantial and
informed experience
NOTE: Suggested services are always optional. When presenting
suggested repairs to the customer, you must present the
facts, allowing the customer to draw their own conclusions
and make an informed decision about how to proceed.
ENGINE ASSEMBLIES
SERVICE PROCEDURES REQUIRED AND SUGGESTED FOR PROPER VEHICLE
OPERATION
CYLINDER HEAD ASSEMBLIES
NOTE: A Cylinder Head Assembly is a cylinder head fitted with
valves, associated springs, retainers, and on overhead
camshaft cylinder heads (OHC), camshaft, camshaft
bearings, lash adjusters, tappets and rockers.
CYLINDER HEAD ASSEMBLY INSPECTION









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Condition Code Procedure
Adjustable valve lash is
out of specification ... B ................. Require repair.
Internal component failure
(any component) ........ A ........... ( 1) Require repair or
replacement of cylinder
head assembly.
( 1) - It is Required that all other failure related components
be inspected for cause and condition. Additional components
or assemblies may be Suggested for repair or replacement,
such as a water pump on a short block (reason code 4,
technician's recommendation based on substantial and
informed experience).
Example:
If there is a failed head gasket with an external coolant
leak, in addition to Requiring replacement of the head
gasket, inspection of the following for cause and condition
is Required: Block, Cooling System, Cylinder Head. It may
be Suggested that additional inspections be performed, such
as the other head gasket on a V-type engine.









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LONG BLOCK ASSEMBLIES
NOTE: A Long Block Assembly is a short block assembly together
with a cylinder head assembly and all those components
fitted within the rocker or cam cover, and timing cover

(the whole presented as an assembly). A rebuilt or new
oil pump, or kit shall be supplied or fitted as
appropriate.
LONG BLOCK ASSEMBLY INSPECTION









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Condition Code Procedure
Internal component failure
(any component) ........ A ........... (1) Require repair or
replacement of the long
block assembly.
( 1) - It is Required that all other failure related components
be inspected for cause and condition. Additional components
or assemblies may be Suggested for repair or replacement
such as a water pump on a short block (reason code 4,
technician's recommendation based on substantial and
informed experience).
Example:
If there is a failed head gasket with an external coolant
leak, in addition to Requiring replacement of the head
gasket, inspection of the following for cause and
condition is Required: Block, Cooling System, Cylinder
Head. It may be Suggested that additional inspections be
performed, such as the other head gasket on a V-type
engine.









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SHORT BLOCK ASSEMBLIES
NOTE: A Short Block Assembly is a cylinder block and all those
components contained within the limits of the block deck
or decks, the pan rail, the block rear face and the
timing cover (where fitted), including the crankshaft.
SHORT BLOCK ASSEMBLY INSPECTION









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Condition Code Procedure
Any internal component
failure ................ A ........... ( 1) Require repair or
replacement of the short
block assembly.
( 1) - It is Required that all other failure related components
be inspected for cause and condition. Additional
components or assemblies may be Suggested for repair or
replacement, such as a water pump on a short block
(reason code 4, technician's recommendation based on
substantial and informed experience).
Example:
If there is a failed head gasket with an external coolant
leak, in addition to Requiring replacement of the head
gasket, inspection of the following for cause and condition
is Required: Block, Cooling System, Cylinder Head. It may
be Suggested that additional inspections be performed,
such as the other head gasket on a V-type engine.









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Wire lead shorted ....... A .. Require repair or replacement.
(1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
repair or replacement.
( 3) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable;
check for accepted cleaning procedure.









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MOTOR MOUNTS
MOTOR MOUNT INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Broken .................. A ............ Require replacement.
Leaking (hydraulic
mount) ................. A ............ Require replacement.
Mounting hole worn,
affecting performance .. A ............ Require replacement.
Mounting hole worn, not
affecting performance .. .. ........ No service suggested or
required.
Rubber deteriorated,
affecting performance .. A ............ Require replacement.
Rubber deteriorated, not
affecting performance .. .. ........ No service suggested or
required.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.









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O-RINGS, GASKETS, SEALS AND SPRING LOCKS
O-RING, GASKET, SEAL AND SPRING LOCK INSPECTION








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Condition Code Procedure
Leaking ................. A ............ ( 1) Require repair or
replacement.
( 1) - Require inspection of mating and sealing surface and
repair or replace as necessary.









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O2 SENSORS
O2 SENSOR INSPECTION








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Condition Code Procedure

Idle Speed Control Actuator ............................... ISC
Mix Control Solenoid .............................. MC Solenoid
Secondary Air Injection System Management Device .... AIR, PAIR
Vacuum Regulator Solenoid .................................. ..
Waste Gate Control Solenoid ................................ ..









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SHROUDS, BAFFLES AND DEFLECTORS
SHROUD, BAFFLE AND DEFLECTOR INSPECTION








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Condition Code Procedure
Application incorrect,
affecting cooling system
performance ............ A . Require repair or replacement.
Attaching hardware
broken ................. A .. Require repair or replacement
of hardware.
Attaching hardware
missing ................ C ......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A .. Require repair or replacement
of hardware.
Bent, affecting cooling
system performance ..... A . Require repair or replacement.
Blocked, affecting cooling
system performance ..... A . Require repair or replacement.
Broken, affecting cooling
system performance ..... A . Require repair or replacement.
Cracked, affecting cooling
system performance ..... A . Require repair or replacement.
Loose, affecting cooling
system performance ..... A ................ Require repair.
Loose, not affecting
cooling system
performance ............ 2 ................ Suggest repair.
Missing, affecting cooling
system performance ..... C ........... Require replacement.









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SPARK PLUGS
NOTE: You are not required to replace spark plugs in sets.
However, you may suggest replacement of the other plugs
for preventive maintenance.
SPARK PLUG INSPECTION









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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Electrode eroded ........ 1 ............ Suggest replacement.
Fouled .................. A ........... ( 1) Require repair or
replacement.
Gap incorrect ........... B .. Require repair or replacement.
Insulation broken ....... A ............. Require replacement
Insulator cracked ....... A ............ Require replacement.
Leaking compression ..... A .. Require repair or replacement.
Maintenance interval .... 3 ............ Suggest replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads

missing) ............... A ............ Require replacement.
(1) - Determine cause of fouling and suggest repair.









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SPRING LOCKS
SPRING LOCK INSPECTION








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Condition Code Procedure
Leaking ................. A ........... ( 1) Require repair or
replacement.
( 1) - Require inspection of mating and sealing surface and
repair or replace as necessary.









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SUPER CHARGERS
SUPER CHARGER INSPECTION








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Condition Code Procedure
Attaching hardware
damaged, affecting
operation or
performance ............ A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Bearing noisy ........... A ............ Require replacement.
Bearing worn ............ A ............ Require replacement.
Boost pressure
incorrect .............. A ........... ( 1) Require repair or
replacement.
Clearance out of
specification .......... B .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Noisy ................... 2 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A .. Require repair or replacement.
( 1) - Boost pressure problems may be caused by other systems or
components.









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SWITCHES
SWITCH INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement

Roll-Over Check Valve
When valve is inverted, a stainless steel ball pushes a
plunger against its seat, blocking fuel flow through valve.
Charcoal Canister
All models are equipped with a dual-purge type canister. An
inlet is provided for carburetor fuel bowl vapors and another one for
fuel tank vapors. The outlet is connected to intake manifold vacuum.
A secondary purge fourth nipple connects to carburetor ported vacuum.
During engine operation, manifold vacuum draws fresh air
through inlet filter in bottom of canister and purges stored vapors.
When ported vacuum reaches 12 in. Hg, secondary purge circuit is
opened and canister purges at a much higher rate.
Carburetor Bowl Vent
The carburetor bowl vent provides an outlet for fuel vapors
when engine is not operating. During engine operation, fuel bowl is
vented to inside of air cleaner. The bowl is automatically closed by
mechanical link to throttle when engine is started.
MAINTENANCE
No adjustments are required with this system. Replace air
inlet filter (if equipped) in bottom of charcoal canister every
30,000 miles. Regular inspection should be made and defective
components replaced as necessary.

ECU is a digital microprocessor computer. Data sensors
provide the ECU with engine operating information in varying
electrical signals. ECU calculates this information and corrects
air/fuel ratio, ignition timing, and emission control as needed to
maintain efficient engine operation. Other ECU output signals control
upshift indicator light (manual transmission only), ignition module
dwell and A/C clutch operation.
UPSHIFT INDICATOR
On vehicles equipped with a manual transmission, ECU
controls upshift indicator light. Indicator light is normally
illuminated when ignition is turned on without engine running.
Indicator light is turned off when engine is started.
Indicator light will be illuminated during engine operation
in response to engine load and speed. If transmission is not shifted,
ECU will turn light off after 3 to 5 seconds. A switch located on
transmission prevents indicator light from being illuminated when
transmission is shifted to highest gear.
DATA SENSORS & SWITCHES
Manifold Absolute Pressure (MAP) Sensor
MAP sensor is located in engine compartment on firewall,
behind engine. MAP sensor monitors manifold vacuum via a vacuum line
from intake manifold to sensor.
MAP sensor supplies an electrical signal which keeps ECU
informed of manifold vacuum and barometric pressure conditions. This
information is combined with data supplied by other sensors to
determine correct air/fuel ratio.
Oxygen Sensor
Oxygen (O2) sensor is mounted in exhaust manifold where it
is exposed to exhaust gas flow. Its function is to monitor oxygen
content of exhaust gases and to supply ECU with a voltage signal
directly proportional to this content.
If oxygen content of exhaust gases is high (lean air/fuel
mixture), voltage signal to ECU is low. As oxygen content decreases
(mixture becomes richer), signal voltage increases.
In this way, ECU is kept constantly informed of air/fuel
ratio. ECU can then alter fuel injector "on" time, in response to
these signals, to obtain best air/fuel ratio of 14.7:1 under any
given operating conditions.
O2 sensor is equipped with a heating element that keeps
sensor at proper operating temperatures. Maintaining correct sensor
temperatures at all times guarantees a more accurate signal to ECU.
By using an O2 heater, fuel control system may also enter "closed
loop" operating mode sooner and maintain this mode, even during
periods of extended idle.
Temperature Sensors
There are 2 temperature sensors used on this system.
Manifold Air Temperature (MAT) sensor, mounted in intake manifold,
measures temperature of incoming air/fuel mixture and Coolant
Temperature Sensor (CTS), located on left side of cylinder block just
below the exhaust manifold, measures temperature of engine coolant.
Information provided by these 2 sensors to ECU allows ECU to
demand slightly richer air/fuel mixtures and higher idle speeds
during cold engine operation.
Throttle Position Sensor (TPS)
TPS is regulated by movement of throttle shaft. It is