1988 JEEP CHEROKEE sensor

Fig. 1: Oxygen Sensor Location
B. Replace Catalytic Converter
WARNING: IF TORCHES ARE USED WHEN WORKING ON THE EXHAUST SYSTEM,
DO NOT ALLOW THE FLAME NEAR THE FUEL LINES.
1. Remove and discard the nuts, bolts and gasket at the front of the
converter and the exhaust pipe clamp at the rear (see Fig. 2).
NOTE: Use penetrating oil if necessary.

2. Peel the label from its backing and apply it near the Vehicle
Emissions Control Information Label on the underside of the hood.
D. Complete Proof of Correction Form
1. Complete a Vehicle Emission Recall Proof of Correction Form and
supply it to the vehicle owner.
COMPLETION REPORTING AND REIMBURSEMENT
Claims for vehicles which have been serviced must be submitted on
the DIAL System Claims submitted will be used by Chrysler to record
recall service completions and provide dealer payments.
Use the following labor operation number and time allowance:
Labor
Operation Time
Number Allowance




















Replace oxygen sensor and catalytic converter 25617182 0.8 Hours
Add the cost of the recall parts package plus applicable dealer
allowance to your claim.
PARTS RETURN
Removed catalytic converters must be returned to the Warranty
Material Return Center.
NOTE: See Warranty Policy and Procedure Manual, Chapter 6, Subsection
H for complete recall claim processing and material return
instructions.
VEHICLE NOT AVAILABLE
If a vehicle is not available for service for a known reason, let us
know by filling out the pre-addressed Vehicle Disposition Form portion
of the Owner Notification Form, or describe the reason on a postcard
and mail to:
Chrysler Corporation 429-10-04
P.O. Box 1919
Detroit, Michigan 48231-1919
Following the above procedures will expedite the processing of your
claim.
If you have any questions or need assistance in completing this
action, please contact your Zone Service Office.
Customer Services Field Operations
Chrysler Corporation
CUSTOMER NOTIFICATION LETTER









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EMISSIONS RECALL TO REPLACE YOUR VEHICLE'S
OXYGEN SENSOR AND CATALYTIC CONVERTER
Dear Jeep Vehicle Owner:

Chrysler Corporation has determined that some 1989 and 1990 Jeep
Cherokee, Comanche and Wrangler vehicles equipped with a 2.5L engine,
may be in violation of Federal Emissions Standards.
The Problem is... The oxygen sensor and catalytic convener on your
vehicle (identified on the enclosed form), may be
susceptible to failure. This could result in
hydrocarbon (HC), carbon monoxide (CO) and oxides
of nitrogen (NOx) emission levels above the
allowable limits, which were established to protect
the public health from the dangers of air pollution.
What you must do... * Simply contact your Jeep dealer to schedule
a service appointment. Ask the dealer to hold
parts for your vehicle or order them prior to
your appointment.
* Bring the enclosed Owner Notification Form with
you to your dealer. It tells the dealer what
service is required for your vehicle.
What Chrysler and Chrysler will repair your vehicle free of charge
your dealer will do... (parts and labor). To do this, your dealer will
replace the oxygen sensor and catalytic
converter. The service will take about one hour
but additional time may be required depending on
how service work is scheduled and processed.
If you need help... If you have trouble getting your vehicle
repaired, please call the Chrysler Customer
Center, toll free, at 1-800-853-1403.
A representative will assist you in getting your
vehicle repaired. If you are still unable to
obtain the repair as described in this letter
within a reasonable time, you may also contact
the Manufacturers Operations Division of the
Environmental Protection Agency (6405J), 401 M
Street, S.W., Washington, D.C. 20460.
In order to ensure your full protection under the emission warranty
made applicable to your vehicle under Federal law, and your right to
participate in future recalls, it is recommended that you have your
vehicle serviced as soon as possible. Failure to do so could legally
be determined to be a lack of proper maintenance of your vehicle.
Further, without this repair your vehicle may fail a state or local
emission inspection test.
We're sorry for any inconvenience, but trust that you understand our
interest in clean air and your continuing satisfaction with our
product. Thanks for your attention to this important matter.
Customer Services Field Operations
Chrysler Corporation

EM IS SIO NS S TA N DAR DS

1988 J e ep C hero ke e
1988 EMISSION & TUNE-UP STANDARDS
MANUFACTURING STANDARDS
Federal and state governments have established air quality
standard during the past 20 years. Automobile manufacturers design
their vehicles to conform to standards where the vehicle will be sold
and operated. These standards cover carbon monoxide (CO), hydrocarbons\
(HC) and oxides of nitrogen (NOx).
Federal and California Standards which must be met by
manufacturers are specified in units easily measured in a testing
laboratory. Since 1970, these standards have been in "grams per mile".
This means no vehicle, whether 2-cylinder or V8, may emit more than a
set weight (in grams) of pollutants for each mile travelled. Since
large engines burn more fuel per mile than do small engines, they must
be "cleaner" per gallon burned if they are to meet these standards.
When manufacturers certify vehicle models prior to sale,
the vehicles are placed on a dynamometer and the exhaust gases are
collected in a bag. After the vehicle runs for a specified time, the
gases are analyzed and weighed. Engines and emission systems are
designed so the weight of emissions will be less than the specified
grams per mile standard.
Infra-red exhaust analyzers are commonly used in vehicle test
stations. The analyzer uses a test probe placed in the exhaust stream
to sample the exhaust gases, and measure the percentage of CO and the
parts per million of HC. These are not the same units used by the
manufacturer when the vehicle is certified. The NOx emissions cannot
be measured by an infra-red exhaust analyzer. Laboratory equipment
must be used to determine NOx emissions.
TUNE-UP STANDARDS
The technician must use the proper specifications when
adjusting the vehicle during a tune-up. The first few years of
emission-regulated vehicles were adjusted using an exhaust gas
analyzer which measured CO and HC.
In the past few years, manufacturers have produced much
cleaner running vehicles. The CO (percentage) and HC (ppm) have beco\
me
very low, especially when measured downstream of catalytic converter.
It has become difficult to measure the effect of fuel and ignition
adjustments.
One solution to this problem for vehicles using carburetors
requires the use of artificially-enriched propane adjustments. The
added propane increases or decreases engine RPM for evaluation of
carburetor rich/lean setting. This allows the technician to check
carburetor setting quickly and accurately.
As computer-controlled systems were developed, it became
possible for the vehicles to adjust the air/fuel ratio, ignition
timing and emission control device operation throughout the entire
driving range. These computer control systems use a variety of sensors
that provide the electronic control unit with information on vehicle
speed, altitude of vehicle operation and transmission gear position,
along with engine operating conditions.
Fuel delivery to achieve a lean air/fuel ratio is controlled
by the computer. The computer controls the on/off (duty cycle) time of\
the fuel injector(s) or carburetor mixture control solenoid to achieve\
leanest possible air/fuel ratio while maintaining good driveability.
Although most repair shops have exhaust gas analyzers,
computer-controlled vehicles normally do not have a CO and HC

\003
EN G IN E R EM OVA L - 6 -C YL

1988 J e ep C hero ke e
1988 ENGINES
Jeep - Engine Removal - 6-Cylinder
Cherokee, Comanche, Wagoneer, Wrangler
6-CYLINDER ENGINES
4.0L
1) Scribe hinge locations, remove engine compartment light
(if equipped) and remove hood. Disconnect battery cables and remove
battery. Drain cooling system.
2) Disconnect wire connectors from alternator, ignition coil
and distributor. Disconnect oil pressure sender wire, starter wires
and fuel injector wiring harness (if equipped). Detach 2 fuel pipe
quick connect couplings at left inner fender panel. Disconnect engine
ground strap and remove air cleaner.
3) Disconnect the vacuum purge hose at fuel vapor canister
tee. Disconnect wire from idle speed actuator and oxygen sensor.
Detach throttle cable from bracket and disconnect throttle valve rod
at bellcrank. Remove upper and lower radiator hoses.
4) On automatic transmission models, disconnect the
transmission fluid cooler tubing. On all models, remove fan shroud and
radiator. Remove fan and spacer or Tempatrol fan assembly. Hold fan
pulley to water pump flange using 5/16" x 1/2" SAE capscrew while
crankshaft is rotated.
5) Disconnect cruise control cable (if equipped). Disconnect\
wires from starter motor solenoid and disconnect CEC system harness.
Remove power brake vacuum check valve from booster (if equipped).
6) Disconnect power steering hoses from steering gear (if
equipped). Drain power steering pump reservoir and plug end of hoses.
Cap all fittings on steering gear and hoses. Raise and support
vehicle. Remove starter. Remove flywheel housing access cover.
7) Remove upper and loosen lower bellhousing-to-engine bolts.
Attach lifting equipment to engine. Raise engine off front mounts.
Place support under bellhousing. Remove remaining bellhousing-to-
engine bolts. Lift engine out of engine compartment.
4.2L
1) Remove battery and drain cooling system. Remove air
cleaner and engine compartment light from hood. Scribe hinge location
and remove hood. Disconnect and plug front fuel line at pump and fuel
return line at frame.
2) Disconnect heater hoses at heater. Label and disconnect
all wiring, lines, linkage and hoses at engine. Remove vacuum switch
assembly bracket from cylinder head cover. Remove both radiator hoses
and automatic transmission oil lines (if equipped) at radiator. Remove\
radiator and shroud.
3) Remove fan and spacer. Use 5/16" x 1/2" SAE bolt to hold
fan pulley to water pump flange. Remove starter and disconnect engine
ground strap. Remove engine mount-to-bracket nuts. Disconnect exhaust
pipe at manifold.
4) Discharge A/C system (if equipped). Disconnect and plug
hose or port openings at compressor. Disconnect hoses at power
steering gear and drain reservoir. Remove power brake vacuum check
valve. Remove bracket bolt for automatic transmission filler tube (if
equipped).
5) Lift and support vehicle. On models with automatic

\003
* E N G IN E S YSTE M S U NIF O RM IN SPEC TIO N G UID ELIN ES *

1 988 J e ep C hero ke e
GENERAL INFORMATION
Engine Performance and Maintenance Motorist Assurance Program
Standards For Automotive Repair
All Makes and Models
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
CONTENTS
Motorist Assurance Program (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
OVERVIEW OF SERVICE REQUIREMENTS AND SUGGESTIONS
Engine Assemblies
CYLINDER HEAD ASSEMBLIES
LONG BLOCK ASSEMBLIES
SHORT BLOCK ASSEMBLIES
Engine Components
ACCELERATOR PEDAL POSITION SENSORS
ACCESSORY BELTS
ACCESSORY PULLEYS
ACTUATORS
AIR CONDITIONING CYCLING SWITCHES
AIR CONDITIONING PRESSURE SENSORS
AIR DUCTS AND TUBES
AIR FILTER ELEMENTS
AIR FILTER GASKETS
AIR FILTER HOUSINGS AND GASKETS
AIR FUEL RATIO SENSORS
AIR INJECTION CONTROL SOLENOIDS
AIR PLENUMS
AIR PUMP BELTS
AIR PUMPS (ELECTRIC-DRIVEN)
AIR TUBES
ASPIRATOR, CHECK AND DECEL VALVES
BAFFLES
BALLAST PRIMARY SUPPLY RESISTOR WIRES
BALLAST RESISTORS AND PRIMARY SUPPLY RESISTOR WIRES
BAROMETRIC PRESSURE SENSORS
BATTERIES
BATTERY CABLES, WIRES AND CONNECTORS
BATTERY CONNECTORS
BATTERY TRAYS AND HOLD DOWN HARDWARE
BATTERY WIRES
BELT-DRIVEN AIR PUMPS
BELT IDLER ASSEMBLIES (ACCESSORY AND CAM BELTS)
BELT TENSIONERS (ACCESSORY AND CAM BELTS)
BOOST CONTROL MECHANISMS
CAMSHAFT POSITION SENSORS
CARBURETORS AND CHOKES
CASTING CORE PLUGS AND EXPANSION PLUGS
CHARGE AIR COOLERS "INTERCOOLERS" (CAC)
CHECK VALVES
CHOKES

CLUTCH PEDAL POSITION SWITCHES
COLD START INJECTORS
CONNECTORS
COOLANT
COOLANT RECOVERY TANKS
COOLING FAN MOTOR MODULES
COOLING FAN MOTOR RELAYS AND MODULES
COOLING FAN MOTOR RESISTORS
COOLING FAN MOTOR SENSORS AND SWITCHES
COOLING FAN MOTOR SWITCHES
COOLING FAN MOTORS
CRANKSHAFT POSITION SENSORS
DECEL VALVES
DEFLECTORS
DIP STICKS AND TUBES
DIP STICK TUBES
DISTRIBUTOR ADVANCES AND RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR BOOTS AND SHIELDS
DISTRIBUTOR CAPS
DISTRIBUTOR RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR ROTORS
DISTRIBUTOR SHIELDS
DISTRIBUTORS
EARLY FUEL EVAPORATION VALVES (HEAT RISER ASSEMBLIES)
EGR COOLERS
EGR EXHAUST MANIFOLD PASSAGES
EGR INTAKE AND EXHAUST MANIFOLD PASSAGES
EGR PLATES AND COOLERS
ELECTRONIC SPARK CONTROL MODULES
ELECTRONIC TRANSMISSION CONTROL DEVICES
ELECTRONIC TRANSMISSION FEEDBACK DEVICES
ENGINE COOLANT TEMPERATURE SENSORS
ENGINE COOLING SYSTEMS
ENGINE COVERS (OIL PAN, VALVE COVER, TIMING COVER)
ENGINE OIL
ENGINE OIL CANISTERS
ENGINE OIL COOLERS (EXTERNAL)
ENGINE OIL DRAIN PLUGS AND GASKETS
ENGINE OIL FILTERS AND CANISTERS
ENGINE OIL GASKETS
ENGINE OIL PRESSURE GAUGES (MECHANICAL)
EVAPORATIVE EMISSION (EVAP) CANISTER FILTERS
EVAPORATIVE EMISSION (EVAP) CANISTER PURGE DEVICES
EVAPORATIVE EMISSION (EVAP) CANISTERS
EVAPORATIVE EMISSION (EVAP) FEEDBACK DEVICES
EXHAUST GAS RECIRCULATION DEVICES
EXHAUST GAS RECIRCULATION FEEDBACK DEVICES
EXPANSION PLUGS
FAN CONTROL SENSORS
FUEL
FUEL ACCUMULATORS AND DAMPERS
FUEL AND COLD START INJECTORS
FUEL DAMPERS
FUEL DELIVERY CHECK VALVES
FUEL DISTRIBUTORS (BOSCH CIS)
FUEL FILLER NECKS AND RESTRICTORS
FUEL FILTERS
FUEL INJECTORS
FUEL LEVEL SENDERS7
FUEL PRESSURE REGULATORS
FUEL PUMPS (IN-TANK AND EXTERNAL, ELECTRICAL OR MECHANICAL)
FUEL RAILS
FUEL RESTRICTORS

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