1988 JEEP CHEROKEE sensor
[x] Cancel search: sensorPage 723 of 1378
Terminal burned, affecting
performance ............ A ............ (1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
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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MASS AIR FLOW (MAF) SENSORS
MASS AIR FLOW (MAF) SENSOR INSPECTION \
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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware threads
damaged ................ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Page 726 of 1378
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
Page 732 of 1378
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... (1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Inoperative includes intermittent operation or out of
OEM specification. Refer to OEM recommended service'
procedures.
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POWER STEERING PRESSURE SENSORS
POWER STEERING PRESSURE SENSOR INSPECTION \
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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Restricted, affecting
performance ............ A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
Page 738 of 1378
Wire lead open .......... A .. Require repair or replacement.
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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SENSORS AND ACTUATORS
NOTE: Conditions pertaining to the sensors and actuators listed
in this section may be found under the name of the sensor
or actuator.
SENSOR ABBREVIATION TABLE
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Sensor Abbreviation
Accelerator Pedal Position Sensor ......................... APP
Air Conditioning Cycling Switch ............................ AC
Air Conditioning Pressure Sensor ........................... ..
Air Fuel Ratio Sensor ...................................... ..
Barometric Pressure Sensor ............................... BARO
Camshaft Position Sensor .................................. CMP
Clutch Pedal Position Switch .............................. CPP
Cooling Fan Motor Sensors and Switches ..................... ..
Crankshaft Position Sensor ................................ CKP
Electronic Transmission Feedback Devices ................... ..
Engine Coolant Temperature Sensor ......................... ECT
Evaporative Emission feedback devices ...................... ..
Exhaust Gas Recirculation feedback devices ................. ..
Fan Control Sensor ......................................... FC
Intake Air Temperature Sensor ............................. IAT
Knock Sensor ............................................... KS
Manifold Absolute Pressure Sensor ......................... MAP
Mass Air Flow Sensor ...................................... MAF
O2 Sensor ................................................. O2S
Park Neutral Position Switch .............................. PNP
Power Steering Pressure Sensor ............................ PSP
Thermal Vacuum Valve ...................................... TVV
Throttle Position Sensor ............................ TP Sensor
Throttle Position Switch ................................... ..
Transmission Range Switch ........................... TR Switch
Vehicle Speed Sensor ...................................... VSS
Volume Air Flow Sensor .................................... VAF
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ACTUATOR ABBREVIATION TABLE \
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Actuator Abbreviation
Air Injection Control Solenoid ............................. ..
Electronic Transmission control devices .................... ..
Evaporative Emission Canister ............................ EVAP
Purge Device ............................................... ..
Exhaust Gas Recirculation Device .......................... EGR
Fuel Injector .............................................. ..
Idle Air Control .......................................... IAC
Page 745 of 1378
Bracket loose, affecting
performance ............ A .. Require repair or replacement.
Bracket loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Bracket missing ......... C ............ Require replacement.
Broken .................. A ............ Require replacement.
Cracked ................. A .. Require repair or replacement.
Disconnected ............ A .. Require repair or replacement.
Kinked .................. A .. Require repair or replacement.
Melted .................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Noisy ................... 2 .. Suggest repair or replacement.
Out of adjustment ....... B ........... (1) Require repair or
replacement.
Routed incorrectly ...... 2 ................. Suggest repair.
Seized .................. A .. Require repair or replacement.
( 1) - Follow OEM recommended adjustment procedures. Require
repair or replacement if out of specification.
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THROTTLE POSITION SENSORS
THROTTLE POSITION SENSOR INSPECTION \
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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A .. ( 1) Require repair or replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
Page 752 of 1378
(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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VACUUM TUBES
See VACUUM HOSES, TUBES AND CONNECTIONS (NON-METALLIC) .
VEHICLE SPEED SENSORS
VEHICLE SPEED SENSOR INSPECTION \
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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Page 753 of 1378
Wire lead open .......... A .. Require repair or replacement.
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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VOLUME AIR FLOW SENSORS
VOLUME AIR FLOW SENSOR INSPECTION \
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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Restricted, affecting
performance ............ A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Page 772 of 1378
\003
FU EL IN JE C TIO N S YSTE M - M ULTI- P O IN T
1988 J e ep C hero ke e
1988 Electronic Fuel Injection
JEEP MULTI-POINT
4.0L Cherokee, Comanche, Wagoneer
DESCRIPTION
The Multi-Point Electronic Fuel Injection (EFI) system is an
electronically controlled system which combines electronic sequential
fuel injection and electronic spark advance systems. Main sub-systems
consist of: air induction, fuel delivery, fuel control, emission
control, Electronic Control Unit (ECU), data sensors and switches.
Air induction system includes air cleaner, throttle body,
Throttle Position Sensor (TPS) and the Idle Speed Stepper (ISS) moto\
r.
Fuel delivery system provides fuel from fuel pump to the
fuel control system. Fuel system is composed of an in-tank electric
fuel pump, fuel filter and return line. Power is provided to operate
fuel pump through a fuel pump relay located on right inner fender
panel.
Fuel control system handles actual fuel delivery into the
engine. Fuel pressure regulator maintains a constant fuel pressure of
31-39 psi (2.1-2.7 kg/cm
). In addition to the regulator, fuel
system consists of the fuel rail and 4 fuel injectors. On MPI engine,
ECU controls EGR/EVAP solenoid operation.
The ECU is a digital microprocessor computer. ECU receives
input signals from various switches and sensors. ECU then computes
fuel injector pulse width ("on" time), spark advance, ignition module
dwell, idle speed, canister purge cycles, EGR flow and feedback
control from this information.
OPERATION
AIR INDUCTION
Air is drawn into combustion chamber through air cleaner and
intake manifold. Amount of air entering engine is controlled by
position of throttle body valve. Throttle body houses throttle
position sensor (TPS) and idle speed solenoid (ISS) motor. TPS is an\
electrical resistor which is connected to throttle valve. TPS
transmits a signal to ECU in relation to throttle valve angle. This
signal is used in calculations to determine injector pulse width to
provide adequate air/fuel mixture.
ECU controls idle speed by providing appropriate voltage
outputs to move ISS motor pin inward or outward to maintain a
predetermined idle speed. ECU continuously monitors TPS and ISS motor
and issues change commands to injectors to increase or decrease
amount of fuel injected.
FUEL DELIVERY
Power to fuel pump relay is supplied from ignition switch
when in "ON" or "START" position, at which time the ECU supplies a
ground for fuel pump relay. When relay contacts are closed, power is
applied to fuel pump.
Fuel is drawn through one end of a roller-type electric fuel
pump, compressed and forced out opposite end. Pump capacity is
greater than maximum engine consumption so that pressure in fuel
system is always maintained.