Chrysler PT Cruiser 2001 Service Manual Supplement page 1108

PT
DESCRIPTION AND OPERATION
INJECTION SYSTEM . . . . . . . . . . . . . . . . . . . . . . 21
PCM REPLACEMENT . . . . . . . . . . . . . . . . . . . . . 22
MODES OF OPERATION . . . . . . . . . . . . . . . . . . . 22
SYSTEM DIAGNOSIS. . . . . . . . . . . . . . . . . . . . . . 24
PROGRAMMABLE COMMUNICATIONS
INTERFACE (PCI) BUS . . . . . . . . . . . . . . . . . . . 24
POWERTRAIN CONTROL MODULE. . . . . . . . . . . 24
PCM GROUND. . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5-VOLT SUPPLY—PCM OUTPUT . . . . . . . . . . . . . 26
8-VOLT SUPPLY—PCM OUTPUT . . . . . . . . . . . . . 26
FUEL CORRECTION or ADAPTIVE MEMORIES . . 26
AUTOMATIC SHUTDOWN (ASD) SENSE—
PCM INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
BATTERY VOLTAGE—PCM INPUT. . . . . . . . . . . . 27
CLUTCH INTERLOCK/UPSTOP SWITCH . . . . . . . 27
ENGINE COOLANT TEMPERATURE
SENSOR—PCM INPUT . . . . . . . . . . . . . . . . . . . 28
HEATED OXYGEN SENSORS—PCM INPUT . . . . 29
IGNITION SENSE—PCM INPUT . . . . . . . . . . . . . . 30
INLET/INTAKE AIR TEMPERATURE
SENSOR—PCM INPUT . . . . . . . . . . . . . . . . . . . 30
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—PCM INPUT . . . . . . . . . . . . . . . . . . . 31
POWER STEERING PRESSURE SWITCH—
PCM INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
SENSOR RETURN—PCM INPUT . . . . . . . . . . . . . 32
SCI RECEIVE—PCM INPUT. . . . . . . . . . . . . . . . . 32
THROTTLE POSITION SENSOR—PCM INPUT . . 32
VEHICLE SPEED SIGNAL—PCM INPUT . . . . . . . 33
DESCRIPTION AND OPERATION
INJECTION SYSTEM
OPERATION
All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power-
train Control Module (PCM) operates the fuel injec-
tion system.
The PCM regulates:
• Ignition timing
• Air/fuel ratio
• Emission control devices
• Cooling fan
• Charging system
FUEL INJECTION SYSTEM
TABLE OF CONTENTS
page
AUTOMATIC SHUTDOWN RELAY—PCM
OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
PROPORTIONAL PURGE SOLENOID—PCM
OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
IDLE AIR CONTROL MOTOR—PCM OUTPUT . . . 35
DATA LINK CONNECTOR. . . . . . . . . . . . . . . . . . . 35
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMP—PCM OUTPUT . . . . . . . . . . . . . . . . . . . 36
SCI TRANSMIT—PCM INPUT . . . . . . . . . . . . . . . 36
RADIATOR FAN RELAYS—PCM OUTPUT . . . . . . 36
TACHOMETER—PCM OUTPUT . . . . . . . . . . . . . . 36
THROTTLE BODY . . . . . . . . . . . . . . . . . . . . . . . . 36
REMOVAL AND INSTALLATION
THROTTLE BODY—2.4L ENGINES . . . . . . . . . . . 36
THROTTLE POSITION SENSOR (TPS)—2.4L. . . . 38
IDLE AIR CONTROL MOTOR—2.4L . . . . . . . . . . . 39
INLET AIR TEMPERATURE SENSOR . . . . . . . . . . 39
MAP SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
POWERTRAIN CONTROL MODULE. . . . . . . . . . . 40
OXYGEN SENSOR 1/1 UPSTREAM—2.4L . . . . . . 41
OXYGEN SENSOR 1/2 DOWNSTREAM . . . . . . . . 41
AIR CLEANER . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
FILTER ELEMENT REPLACEMENT . . . . . . . . . . . 42
ENGINE COOLANT TEMPERATURE SENSOR. . . 42
SPECIFICATIONS
VEHICLE EMISSION CONTROL
INFORMATION LABEL . . . . . . . . . . . . . . . . . . . 43
TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
SPECIAL TOOLS
FUEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
• Idle speed
• Vehicle speed control
Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi-
tion to the sensors, various switches also provide
inputs to the PCM.
The PCM can adapt its programming to meet
changing operating conditions.
Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat-
ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust-
ing injector pulse width. Injector pulse width is the
length of time the injector is open.
The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
FUEL SYSTEM 14 - 21
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