Savana 1500 RWD V6-4.3L (2007)
Engine Control Module: Description and Operation
Powertrain Control Module Description
Powertrain
The powertrain has electronic controls to reduce exhaust emissions while maintaining excellent driveability and fuel economy. The powertrain control
module (PCM) is the control center of this system. The PCM monitors numerous engine and vehicle functions. The PCM constantly looks at the
information from various sensors and other inputs, and controls the systems that affect vehicle performance and emissions. The PCM also performs the
diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp
(MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that
is set. The control module supplies a buffered voltage to various sensors and switches. Review the components and wiring diagrams in order to
determine which systems are controlled by the PCM.
The following are some of the functions that the PCM controls:
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The engine fueling
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The ignition control (IC)
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The knock sensor (KS) system
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The evaporative emissions (EVAP) system
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The secondary air injection (AIR) system (if equipped)
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The exhaust gas recirculation (EGR) system
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The automatic transmission functions
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The generator
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The A/C clutch control
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The cooling fan control
Powertrain Control Module Function
The powertrain control module (PCM) constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle
performance and emissions. The PCM also performs diagnostic tests on various parts of the system. The PCM can recognize operational problems and
alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The
problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. The input
and output devices in the PCM include analog-to-digital converters, signal buffers, counters, and output drivers. The output drivers are electronic
switches that complete a ground or voltage circuit when turned on. Most PCM controlled components are operated via output drivers. The PCM
monitors these driver circuits for proper operation and, in most cases, can set a DTC corresponding to the controlled device if a problem is detected.
Malfunction Indicator Lamp (MIL) Operation
The malfunction indicator lamp (MIL) is located in the instrument panel cluster. The MIL will display as either SERVICE ENGINE SOON or one of the
following symbols when commanded ON:
The MIL indicates that an emissions related fault has occurred and vehicle service is required.
The following is a list of the modes of operation for the MIL:
