Chrysler Concorde 1993 Service Manual page 515

14 - 22 FUEL SYSTEMS
• Manifold Absolute Pressure (MAP) Sensor
• Heated Oxygen Sensors
• Ignition sense
• Park/Neutral (from transmission control module)
• SCI Receive
• Speed Control
• Throttle Position Sensor
• Torque Management Input (From Transmission
Control Module)
• Vehicle Speed (from transmission control module)
PCM Outputs:
• Air Conditioning Clutch Relay
• Auto Shutdown (ASD) and Fuel Pump Relays
• Data Link Connector (CCD and SCI Transmit)
• Duty Cycle EVAP Purge Solenoid
• EGR Solenoid
• Fuel Injectors
• Generator Field
• High Speed Fan Relay
• Idle Air Control Motor
• Ignition Coils
• Low Speed Fan Relay
• MTV Solenoid
• Speed Control Relay
• Speed Control Vent Relay
• Speed Control Vacuum Relay
Based on inputs it receives, the powertrain control
module (PCM) adjusts fuel injector pulse width, idle
speed, ignition timing, and canister purge operation.
The PCM regulates the cooling fans, air conditioning
and speed control systems. The PCM changes gener-
ator charge rate by adjusting the generator field.
The PCM adjusts injector pulse width (air-fuel ra-
tio) based on the following inputs.
• Battery Voltage
• Charge Air Temperature Sensor (3.5L Engine)
• Engine Coolant Temperature
• Engine Speed (crankshaft position sensor)
• Exhaust Gas Oxygen Content (heated oxygen sen-
sors)
• Manifold Absolute Pressure
• Throttle Position
The PCM adjusts engine idle speed through the
idle air control motor based on the following inputs.
• Brake Switch
• Engine Coolant Temperature
• Engine Speed (crankshaft position sensor)
• Park/Neutral (transmission gear selection)
• Throttle Position
• Vehicle Speed (from transmission control module)
The PCM adjusts ignition timing based on the fol-
lowing inputs.
• Charge Air Temperature (3.5L engine)
• Engine Coolant Temperature
• Engine Speed (crankshaft position sensor)
• Knock Sensor
• Manifold Absolute Pressure
• Park/Neutral (transmission gear selection)
• Throttle Position
The auto shutdown (ASD) and fuel pump relays are
mounted externally, but turned on and off by the
powertrain control module through the same circuit.
The camshaft and crankshaft signals are sent to
the powertrain control module. If the PCM does not
receive both signals within approximately one second
of engine cranking, it deactivates the ASD and fuel
pump relays. When these relays are deactivated,
power is shut off to the fuel injectors, ignition coils,
fuel pump and the heating element in each oxygen
sensor.
The PCM contains a voltage converter that
changes battery voltage to a regulated 8.0 volts. The
8.0 volts power the camshaft position sensor, crank-
shaft position sensor and vehicle speed sensor. The
PCM also provides a 5.0 volts supply for the engine
coolant temperature sensor, charge air temperature
sensor, manifold absolute pressure sensor and throt-
tle position sensor.
The PCM engine control strategy prevents reduced
idle speeds until after the engine operates for 320 km
(200 miles). If the PCM is replaced after 320 km (200
miles) of usage, update the milage in new PCM. Use
the DRBII scan tool to change the milage in the
PCM. Refer to the appropriate Powertrain Diagnostic
Manual and the DRBII scan tool.
TRANSMISSION CONTROL MODULE
The transmission control module supplies two in-
puts to the PCM:
• Road Speed
• Torque Management (3.5L engine only)
ROAD SPEED
The transmission control module supplies the road
speed and distance traveled inputs to the PCM. From
these inputs and the throttle position sensor input,
the PCM determines when a deceleration condition
occurs.
TORQUE MANAGEMENT (3.5L ENGINE)
The PCM receives the torque management input
from the transmission control module. The PCM re-
ceives the input when the transmission shifts gears.
In response, the PCM shuts off a number of fuel in-
jectors when the transmission shifts gears.
PARK/NEUTRAL SWITCH
The transmissions manual valve lever position sen-
sor supplies the park/neutral input to the powertrain
control module. The park/neutral switch input tells
the PCM whether the transmission is in Park, Neu-
tral, or a drive gear selection. This input effects idle
speed, fuel injector pulse width and ignition timing.