LaCrosse V6-3.6L (2007)
The engine control module (ECM) employs an internal integrated circuit to continuously monitor the knock control evaluation circuit. The knock sensor
(KS) module contains the circuitry that allows the ECM to utilize the KS signals and diagnose the KS sensors and circuitry. If the ECM detects a fault in
the ability of the KS module to sample these signals, a DTC sets.
Data Link Connector (DLC)
The data link connector (DLC) is a 16-pin connector that provides the technician a means of accessing serial data for aid in the diagnosis. This connector
allows the technician to use a scan tool in order to monitor the various serial data parameters, and display the DTC information. The DLC is located
inside of the drivers compartment, underneath the dash.
Malfunction Indicator Lamp (MIL)
The malfunction indicator lamp (MIL) is inside of the instrument panel cluster (IPC). The MIL is controlled by the engine control module (ECM) and
illuminates when the ECM detects a condition that affects the vehicle emissions.
ECM Service Precautions
The engine control module (ECM), 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 ECM
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 (ECM) detect a condition that could result in excessive emissions, the ECM turns ON the malfunction
indicator lamp (MIL) and stores a DTC that is associated with the condition.
Aftermarket (Add-On) Electrical And Vacuum Equipment
Notice: 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.
Notice: 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
Important: In order to prevent possible electrostatic discharge damage to the engine control module (ECM), DO NOT touch the connector
pins on the ECM.
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 zap of a static discharge.
There are several ways for a person to become statically charged. The most common methods of charging are by friction and by induction. An example
of charging by friction is a person sliding across a car seat.
Charging by induction occurs when a person with well insulated shoes stands near a highly charged object and momentarily touches ground. Charges of
the same polarity are drained off leaving the person highly charged with the opposite polarity. Static charges can cause damage, therefore, it is important
to use care when handling and testing electronic components.
