Chrysler 1997 Stratus Convertible RHD Service Manual page 882

BATTERY POSITIVE BATTERY GROUND AIR CLEANER PCM TCM PDC
14 - 28 FUEL SYSTEM
DESCRIPTION AND OPERATION (Continued)
POWER DISTRIBUTION CENTER
The Power Distribution Center (PDC) is located
next to the battery (Fig. 1). The PDC contains the
starter relay, radiator fan relay, A/C compressor
clutch relay, auto shutdown relay, fuel pump relay
and several fuses.
Fig. 1 Power Distribution Center and Powertrain
Control Module
CCD BUS
Various modules exchange information through a
communications port called the CCD Bus. The power-
train control module (PCM) transmits the Malfunction
Indicator Lamp (Check Engine) On/Off signal and
engine RPM on the CCD Bus. The PCM receives the Air
Conditioning select input, transaxle gear position input
and speed control engage inputs over the CCD Bus. The
PCM also receives the air conditioning evaporator tem-
perature signal from the CCD Bus.
The following components access or send informa-
tion on the CCD Bus.
• Instrument Panel
• Body Control Module
• Air Bag System Diagnostic Module
• Full ATC Display Head
• ABS Module
• Transmission Control Module
• Powertrain Control Module
• Overhead Travel Module
POWERTRAIN CONTROL MODULE
The Powertrain Control Module (PCM) is a digital
computer containing a microprocessor. The PCM
receives input signals from various switches and sen-
sors that are referred to as PCM Inputs. Based on
these inputs, the PCM adjusts various engine and
vehicle operations through devices that are referred
to as PCM Outputs.
NOTE: PCM Inputs:
• Air Conditioning Controls
• Battery Voltage
• Battery Temperature Sensor
• Brake Switch
• Camshaft Position Sensor
• Crankshaft Position Sensor
• Engine Coolant Temperature Sensor
• Fuel Level Sensor
• Ignition Switch
• Intake Air Temperature Sensor
• Knock Sensor (2.0/2.4L only)
• Manifold Absolute Pressure (MAP) Sensor
• Oxygen Sensors
• Power Steering Pressure Switch
• SCI Receive
• Speed Control Switches
• Throttle Position Sensor
• Transmission Park/Neutral Switch (automatic
transmission)
• Vehicle Speed Sensor
NOTE: PCM Outputs:
• Air Conditioning Clutch Relay
• Auto Shutdown (ASD) Relay
• Charging Indicator Lamp
• SCI Transmit
• Duty Cycle EVAP Canister Purge Solenoid
• EGR Solenoid
• Fuel Injectors
• Fuel Pump Relay
• Generator Field
• Idle Air Control Motor
• Ignition Coils
• Malfunction Indicator (Check Engine) Lamp
• Radiator Fan Relays
• Speed Control Solenoids
Based on inputs it receives, the PCM adjusts fuel
injector pulse width, idle speed, ignition spark
advance, ignition coil dwell and EVAP canister purge
operation. The PCM regulates the cooling fan, air
conditioning and speed control systems. The PCM
changes generator charge rate by adjusting the gen-
erator field. The PCM also performs diagnostics.
The PCM adjusts injector pulse width (air-fuel
ratio) based on the following inputs.
• Battery voltage
• Coolant temperature
• Exhaust gas content (oxygen sensor)
• Engine speed (crankshaft position sensor)
• Intake air temperature
• Manifold absolute pressure
• Throttle position
The PCM adjusts ignition timing based on the fol-
lowing inputs.
• Coolant temperature
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