Vibe AWD L4-2.4L (2009)
Engine Control Module: Description and Operation
Powertrain Control Module Description
The powertrain control module (PCM) is a precision microprocessor that is an essential part of the electronic control system. The PCM is responsible for
engine and automatic transmission operation. The PCM is located in the engine compartment. The PCM communicates with other vehicle control
modules using the controlled area network (CAN) communication protocol. Outside communication with the PCM is through the data link connector
(DLC) located below the left side of the instrument panel (IP).
The PCM performs the OBD II diagnostic tests of the emission related systems. The PCM supplies a buffered voltage, called reference voltage, to the
various information sensors and switches. The PCM controls most components with an electronic switch that completes a ground circuit when turned
ON. The electronic switch is commonly referred to as an output driver. The PCM is also responsible for a self-diagnosis function and a fail-safe function.
Self-Diagnosis Function
The powertrain control module (PCM) diagnoses any troubles which may occur in the engine control system when the ignition switch is in the ON
position with the engine running. The PCM indicates a malfunction by illuminating the malfunction indicator lamp (MIL) when a fault occurs in any of
the following systems:
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The heated oxygen sensor 1 (HO2S 1)
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The heated oxygen sensor 2 (HO2S 2)
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The engine coolant temperature (ECT) sensor
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The accelerator pedal position (APP) sensors
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The throttle position (TP) sensors
*
The vehicle speed sensor (VSS)
*
The intake air temperature (IAT) sensor
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The mass air flow (MAF) sensor
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The camshaft position (CMP) sensor
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The crankshaft position (CKP) sensor
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The knock sensor (KS) system
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The evaporative emission (EVAP) control system
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The electronic throttle control (ETC) or throttle actuator control (TAC) system
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The CMP actuator solenoid system
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The misfire detection
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The fuel-trim
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The catalyst monitor
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The central processing unit (CPU) of the PCM
When the PCM detects a malfunction in one of the above areas, the PCM will illuminate or flash the MIL in order to notify the driver of the occurrence
of a fault.
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:
