1988 JEEP CHEROKEE Service Repair Manual

"P" ABBREVIATION TABLE
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ABBREVIATION DEFINITION 










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"P" Park 

P/C Printed Circuit 

P/N Park/Neutral 

P/S Power Steering 

PAV Pulse Air Valve 

PC-SOL Purge Control Solenoid 

PCM Powertrain Control Module 

PCS Purge Control Solenoid 

PCSDM Passenger Compartment Sensor/Diagnostic Module 

PCV Positive Crankcase Ventilation 

PFE Pressure Feedback EGR sensor or circuit 

PFI Port Fuel Injection (see MA SEFI) 

PGM-CARB Programmed Carburetor 

PGM-FI Programmed Fuel Injection 

PIP Profile Ignition Pickup 

PNK Pink 

PPL Purple 

PRNDL Park Reverse Neutral Drive Low 

PROM Programmable Read-Only Memory 

psi Pounds Per Square Inch 

PSPS Power Steering Pressure Switch 

PTC Positive Temperature Coefficient 

PTO Power Take-Off 

PWR GND Power Ground circuit 

Pkg. Package 

Press. Pressure 

Prog. Programmed or Programmable 

Pts. Pints 

Pwr. Power 











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"Q" ABBREVIATION TABLE
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Qts. Quarts 











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"R" ABBREVIATION TABLE
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RABS Rear Anti-Lock Brake System 

RAC Remote Accessory Control 

RAM Random Access Memory 

RAP Retained Accessory Power 

RECIRC Recirculation 

RED Red 

RH Right Hand 

ROM Read Only Memory 

RPM Revolutions Per Minute 

RVB Rear Vacuum Break 

RWAL Rear Wheel Anti-Lock Brake 

RWD Rear Wheel Drive 

Recirc. Recirculate or Recirculation 

Reg. Regulator 

Rly. Relay 











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"S" ABBREVIATION TABLE
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ABBREVIATION DEFINITION 










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SAW Spark Angle Word 

SBC Single Bed Converter 

SBEC Single Board Engine Controller 

SC Super Charged 

SCC Spark Control Computer 

SCS Air Suction Control Solenoid 

SDM Supplemental Restraint System Diagnostic Module 

SDU SRS Diagnostic Unit 

SEN Sensor 

SES Service Engine Soon 

SFI Sequential (Port) Fuel Injection 

SIG RTN Signal Return circuit 

SIL Shift Indicator Light 

SIR Supplemental Inflatable Restraint 

SMEC Single Module Engine Controller 

SOHC Single Overhead Cam 

SOL or Sol. Solenoid 

SPFI Sequential Port Fuel Injection 

SPK Spark Control 

SPOUT Spark Output Signal 

SRS Supplemental Restraint System (Air Bag) 

SS 3/4-4/3 Shift Solenoid circuit 

SSI Solid State Ignition 

STAR Self-Test Automatic Readout 

STI Self Test Input circuit 

STO Self-Test Output 

SUB-O2 Sub Oxygen Sensor 

Sen. or Sens. Sensor 

Sol. Solenoid 

Sprchg. Supercharger 

Strg. Steering 

Susp. Suspension 

Sw. Switch 

Sys. System 











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"T" ABBREVIATION TABLE
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T.V. Throttle Valve 

TAB Thermactor Air By-Pass 

TAC Thermostatic Air Cleaner 

TAD Thermactor Air Diverter 

TAN Tan 

TBI Throttle Body Injection 

TCC Torque Converter Clutch 

TCCS Toyota Computer Control System 

TDC Top Dead Center 

TDCL Total Diagnostic Communication Link 

TFI Thick Film Ignition system 

TGS Top Gear Switch (cancels SIL in top gear) 

THERMAC Thermostatic Air Cleaner 

THS Transmission Hydraulic Switch 

TP/TPS Throttle Position Sensor 

TPI Tuned Port Injection 

TPS Throttle Position Sensor/Switch 

TS Temperature Sensor 

TSB Technical Service Bulletin 

TTS Transmission Temperature Switch 

TV Thermovalve 

TWC Three-Way Catalyst 

Temp. Temperature 

Trans. Transaxle/Transmission 











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"V" ABBREVIATION TABLE
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V Valve 

VAF Vane Air Flow sensor or circuit 

VAPS Variable Assist Power Steering 

VAT Vane Air Temperature 

VATS Vehicle Anti-Theft System 

VBATT Vehicle Battery Voltage 

VCC Viscous Converter Clutch 

VIN Vehicle Identification Number 

VIO Violet 

VLR Volt Loop Reserve 

VM Vacuum Modulator 

VM Vane Meter 

VOM Volt-Ohmmeter (Analog) 

VPWR Vehicle Power supply voltage (10-14 volts) 

VREF Voltage Reference (ECA supplied reference voltage 

VRV Vacuum Regulator Valve 

VSC Vehicle Speed Control sensor or signal 

VSS Vehicle Speed Sensor or signal 

VSV Vacuum Switching Valve 

Vac. Vacuum 

Volt. Voltage 











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W/ With 

W/O Without 

WAC WOT A/C Cut-off switch or circuit 

WAC Wide Open Throttle A/C Switch 

WHT White 

WOT Wide Open Throttle 

YEL Yellow 









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\003
A/C C O M PR ESSO R O IL C HEC KIN G

1988 J e ep C hero ke e
A/C General Servicing
COMPRESSOR OIL CHECK
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
ISOLATING COMPRESSOR - GRAND WAGONEER ONLY
1) Connect service gauge set to the compressor service valves
and open compressor valves slightly (turn clockwise). Start engine and\
operate air conditioning. Slowly turn compressor suction valve
clockwise toward closed (front-seated) position.
2) When suction pressure is reduced to zero or less, turn off
engine and compressor and quickly turn suction valve stem in to full
front-seated position. Suction pressure should be slightly above zero.
Turn discharge valve into front-seated position.
3) To check oil lever, slowly open crankcase plug to relieve
any remaining pressure. After oil level is correct, cap service gauge
parts on both valves. Back-seat suction service valve to allow
refrigerant to enter compressor. Open discharge valve halfway.
4) Loosen discharge service valve cap, allowing refrigerant
pressure to force air out of compressor. Back-seat service valve and
tighten cap. Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used
in the air conditioning system. This oil is highly refined and
dehydrated to a point where moisture content is less than 10 parts per
million. The oil container must be tightly closed at all times when
not in use, or moisture will be absorbed from the air and introduced
into the refrigeration system.
DISCHARGING SYSTEM
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. Otherwise,
discharge system completely using approved refrigerant
recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. Do not remove caps until
immediately before connections are made. This will keep entry of air
and moisture to a minimum, reducing the chance of damage to
components.

PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and
all connections have been made, evacuate system throughly with a
vacuum pump. Charge system with proper amount of refrigerant and
perform a leak test. Be sure to check all fittings that have been
opened. After system has been leak tested, make a system performance
check.
SANDEN SD508 5-CYLINDER OIL CHECKING
1) Discharge system using approved refrigerant
recovery/recycling equipment. Remove compressor belt and loosen
mounting bolts. Rotate compressor in brackets until filler plug is at
top. Clean area around filler plug and remove plug slowly. Rotate
front hub plate so notch in lobe is 110 degrees from the bottom. This
rotates ball end of top piston to align with oil fill port and allows
clearance for dipstick. See Fig. 1.
2) Insert compressor dipstick diagonally from right to left
until stop on dipstick contacts filler plug surface. Remove dipstick
and note oil fill level. Each mark on dipstick represents one ounce
of oil. Add oil if necessary to reach 3-4 ounce level.
Fig. 1: Sanden 5-Cylinder Oil Level Checking
YORK - 2-CYLINDER - PURGINE COMPRESSOR

1) Remove gauge set and place caps on service valve ports.
Back-seat the suction service valve to allow refrigerant to enter
compressor.
2) Loosen discharge port valve slightly. Loosen valve port
cap to allow refrigerant to force out air from compressor. Back-seat
the discharge valve and tighten the port cap. Compressor is ready for
service.
YORK - 2-CYLINDER COMPRESSOR OIL CHECKING
1) Operate system for 10 minutes, then stop and isolate
compressor. Loosen filler plug slowly to release any pressure in
crankcase.
2) Use dipstick to check oil level. See Fig. 2. Add oil as
necessary, then install plug with new "O" ring. Purge compressor of
air.
Fig. 2: York A/C Compressor Oil Level Dipstick (Check oil w/ shaft
keyway facing head)
Courtesy of Chrysler Motors.

\003
A/C -H EA TE R S YSTE M - M AN UAL

1988 J e ep C hero ke e
1988 Manual A/C-Heater Systems
JEEP
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
DESCRIPTION
On Cherokee, Comanche and Wagoneer, the Climate Control
System is an integral assembly combining air conditioning, heating and
ventilating capabilities for models with air conditioning. The A/C
registers are built into instrument panel.
On Wrangler models, a dual flow unit with the capability of
recirculating air or drawing air from outside is used. It incorporates
under-dash registers and uses a blend-air type system.
The A/C components include a compressor, condenser, receiver-
drier, a sight glass (in the receiver-to-evaporator line) and
evaporator housing. Evaporator housing contains evaporator core,
expansion valve, thermostat, wiring and drain tube. Blower motor and
fan are located in blower housing, which is attached to evaporator
housing.
Vents provided in evaporator housing are adjustable to direct
air to different positions in vehicle's interior. System controls
include fan and temperature control knobs built into lower evaporator
housing assembly or temperature and mode levers on control panel
integrated with instrument panel.
OPERATION
A/C SYSTEM CONTROLS
Temperature & Fan Control Knobs
(Wrangler)
The right rotary control knob allows selection of desired
temperature. Knob has "OFF" "1", "2" and "3" positions for different
levels of cooling. The left rotary fan switch (knob) controls blower
motor speed. Knob has "OFF", "LOW", "MED" and "HI" positions. Fan will
operate unless mode control lever is in "OFF" position.
The A/C fan switch is a 3-speed unit used in conjunction with
a blower motor resistor. Fan switch controls low, medium and high
speed operation. Switch may be serviced by removing access plate
located on lower evaporator core housing, below control panel.
The A/C temperature control switch has a thermostat unit
built-in. Cooling adjustment is done by turning knob in a clockwise
rotation. For fast, efficient system operation in hot weather, vehicle
should be purged of hot air by driving about 2-3 city blocks with at
least one window open. During this time, temperature control knob
should be rotated clockwise to "MAX" position and fan control knob
placed in "HI" position. This allows evaporator to pre-cool and avoid
typical first blast of warm air.
Temperature Control Panel
(Cherokee, Comanche & Wagoneer)
The upper temperature control (mode) lever includes "MAX",
"NORM", "BI-LEVEL", "VENT", "HEAT" and "OFF" positions. At the far end