SRT-4 L4-2.4L Turbo VIN S (2004)
Powertrain Control Module: Description and Operation
SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical noise ground reference for all of the systems sensors. The sensor return circuit connects to internal
ground circuits within the Powertrain Control Module (PCM).
DATA BUS COMMUNICATION RECEIVE- PCM INPUT
The PCM uses the SCI communication bus to preform engine diagnostics and flash operations. The transmission side of the PCM uses the SCI
communication bus to flash new software. However, diagnostics is performed via the vehicles J1850 bus for the transmission side of the PCM.
IGNITION SENSE- PCM INPUT
The ignition sense input informs the Powertrain Control Module (PCM) that the ignition switch is in the crank or run position.
PCM GROUND
Ground is provided through multiple pins of the PCM connector. Depending on the vehicle there may be as many as two different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground side relays, solenoids, ignition coil or injectors. The signal ground is used for any input that uses
sensor return for ground, and the ground side of any internal processing component.
The PCM case is shielded to prevent RFI and EMI. The PCM case is grounded and must be firmly attached to a good, clean body ground.
Internally all grounds are connected together, however there is noise suppression on the sensor ground. For EMI and RFI protection the housing and
cover are also grounded separately from the ground pins.
PCM
The PCM receives input signals from various switches and sensors that are referred to as PCM Inputs. Based on these inputs, the PCM adjusts various
engine, transmission, and vehicle operations through devices that are referred to as PCM Outputs.
NOTE: PCM Inputs:
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Air Conditioning Controls
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Ambient Air temperature Sensor
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ASD Sense
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Baro/Tip (Turbo)
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Battery Voltage
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Battery Temperature Sensor
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Brake Switch
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Camshaft Position Sensor
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Clutch Upstop Switch
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Clutch Interlock
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Crankshaft Position Sensor
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Engine Coolant Temperature Sensor
