Operation - Chrysler PT Cruiser Service & Repair Manual

8E - 6 ELECTRONIC CONTROL MODULES
POWERTRAIN CONTROL MODULE (Continued)

OPERATION

OPERATION
The PCM receives input signals from various
switches and sensors that are referred to as PCM
Inputs. Based on these inputs, the PCM adjusts var-
ious engine, transmission, and vehicle operations
through devices that are referred to as PCM Outputs
(Fig. 7).
Fig. 7 PCM
NOTE: PCM Inputs:
• Air Conditioning Controls
• Ambient Air temperature Sensor
• ASD Sense
• Baro/Tip (Turbo)
• Battery Voltage
• Battery Temperature Sensor
• Brake Switch
• Camshaft Position Sensor
• Clutch Upstop Switch (1.6L)
• Clutch Interlock
• Crankshaft Position Sensor
• Cruise Control Switch
• Electronic Throttle Control (1.6L only)
• Engine Coolant Temperature Sensor
• Fuel Level Sensor (Bus message)
• Ignition Switch
• Intake Air Temperature Sensor
• J1850
• Knock Sensor (1.6, 2.0, 2.4L only)
• Natural Vacuum Leak Detection (NVLD)
• Manifold Absolute Pressure (MAP) Sensor
• Oil Pressure Switch
• Oxygen Sensors
• Pedal Position Sensor (1.6L has 2 sensors)
• Power Steering Pressure Switch
• SCI Receive
• Speed Control Switches
• Throttle Position Sensor (1.6L has 2 TPS Sen-
sors)
• Transmission Control Relay (Switched B+)
• Transmission Input Shaft Speed Sensor
• Transmission Output Shaft Speed Sensor
• Transmission Pressure Switches (L/R, 2/4, OD)
• Transmission Range Sensor (TRS)
• Transmission Oil Temperature Sensor (Integral
to TRS)
• Vehicle Speed Sensor (MTX-equipped models)
NOTE: PCM Outputs:
• Air Conditioning Clutch Relay
• Auto Shutdown (ASD) Relay
• Charging Indicator Lamp (Bus Message)
• SCI Transmit
• Proportional Purge Solenoid
• EGR Solenoid
• Electronic Throttle Control (1.6L only)
• Fuel Injectors
• Fuel Pump Relay
• Generator Field
• Idle Air Control Motor (2.0/2.4L)
• Ignition Coils
• J1850
• Malfunction Indicator (Check Engine) Lamp
(Bus Message)
• Oxygen Sensors Heater Controls
• Radiator Fan Relays
• Speed Control Solenoids (2.0/2.4L)
• Transmission Control Relay
• Transmission Solenoids (LR/CC, 2/4, OD, and
UD)
• Transmission PRNDL Position (to Cluster)
• Transmission Torque Reduction Request (Inter-
nal to PCM)
• Transmission Temperature (Internal to PCM and
a Bus Message)
• Vehicle Speed (Manual Transmission)
• 2 Electronic Throttle Control Outputs (1.6L)
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 also determines the appropriate
transmission shift schedule and shift points, depend-
ing on the present operating conditions and driver
demand. The PCM regulates the cooling fan, air con-
ditioning 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
PT