LaCrosse V6-3.8L (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 that 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 DTC is stored any time the control module
illuminates the MIL due to an emissions related fault. The MIL turns OFF after 3 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.
PCM Service Precautions
The powertrain control module (PCM), by design, can withstand the normal current draws that are associated with the vehicle operations. However, care
must be used in order to avoid overloading any of these circuits. When testing for opens or shorts, do not ground or apply voltage to any of the PCM
circuits unless the diagnostic procedure instructs you to do so. These circuits should only be tested with a DMM.
Emissions Diagnosis For State I/M Programs
This OBD II equipped vehicle is designed to diagnose any conditions that could lead to excessive levels of the following emissions:
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Hydrocarbons (HC)
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Carbon monoxide (CO)
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Oxides of nitrogen (NOx)
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Evaporative emission (EVAP) system losses
Should this vehicles on-board diagnostic system, powertrain control module (PCM), detect a condition that could result in excessive emissions, the PCM
turns ON the malfunction indicator lamp (MIL) and stores a DTC that is associated with the condition.
Aftermarket (Add-On) Electrical And Vacuum Equipment
Caution: Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle
components or systems.
Caution: Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent
damage to the vehicle.
Aftermarket, add-on, electrical and vacuum equipment is defined as any equipment installed on a vehicle after leaving the factory that connects to the
vehicles electrical or vacuum systems. No allowances have been made in the vehicle design for this type of equipment.
Add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include
equipment not connected to the vehicle electrical system, such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain
condition is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, the problem may be
diagnosed in the normal manner.
Electrostatic Discharge (ESD) Damage
Note: In order to prevent possible electrostatic discharge damage to the control module, DO NOT touch the connector pins on the control module.
The electronic components that are used in the control systems are often designed to carry very low voltage. The electronic components are susceptible
to damage caused by electrostatic discharge. Less than 100 volts of static electricity can cause damage to some electronic components. By comparison, it
takes as much as 4,000 volts for a person to even feel the effect of a static discharge.
