Vibe FWD L4-2.4L (2009)
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:
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The MIL illuminates when the ignition is turned ON, with the engine OFF. This is a bulb test to ensure the MIL is able to illuminate.
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The MIL turns OFF after the engine is started if a diagnostic fault is not present.
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The MIL remains illuminated after the engine is started if the control module detects a fault. A diagnostic trouble code (DTC) is stored any time
the control module illuminates the MIL due to an emissions related fault. The MIL turns OFF after three consecutive ignition cycles in which a
Test Passed has been reported for the diagnostic test that originally caused the MIL to illuminate.
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The MIL flashes if the control module detects a misfire condition which could damage the catalytic converter.
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When the MIL is illuminated and the engine stalls, the MIL will remain illuminated as long as the ignition is ON.
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When the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition is cycled OFF and then ON.
Fail-Safe Function
When a malfunction occurs within the engine control system, the PCM maintains control over the fuel injection system, the idle speed control system,
etc. The PCM controls these systems by using calculated values and/or backup programs stored within the PCM.
This function is called the fail-safe function. With the fail-safe function, a certain level of engine performance is available even when a malfunction
occurs. The fail-safe function prevents a complete loss of engine performance.
The systems covered by the fail-safe function are as follows:
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The MAF sensor
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The IAT sensor
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The APP sensor
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The TP sensor
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The HO2S heater circuits
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The KS system
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The TAC system
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The CPU in the PCM
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The fuel cut-off for ignition system failures
Control Module Learning Ability
The powertrain control module has a "learning" ability which enables the control module to make corrections for minor variations in the fuel system.
This learning ability can improve driveability. Disconnecting the battery resets the learning process. A change in the vehicle's performance may be
noticed when a reset from a PCM power down occurs. Operating the vehicle under varying conditions will enable the control module to regain any lost
vehicle performance.
In order to initiate the control module learning ability, warm the engine to operating temperature and drive the vehicle at part throttle with moderate
acceleration. Continue to drive the vehicle while including steady cruise and idle speed operation. For the best idle speed quality several key cycles with
a short drive and long idle periods is recommended.
Check Mode
The PCM has the ability to operate in the Normal mode or in the Check Mode. The 2 modes of operation are similar. When the PCM is operating in the
Check mode, the PCM has an increased ability to detect malfunctions. The most significant feature of the Check mode operation is that all B type codes
now run like A type codes. In order to request that the PCM operate in the Check Mode, scan tool communication with the PCM is necessary. For
information on the use of the Check Mode in diagnosing driveability concerns, refer to Service Bay Test (See: Testing and Inspection/Monitors, Trips,
Drive Cycles and Readiness Codes/Service Bay Test).
PCM Output Controls
