There are a number of security methods in operation in the vehicles built using the Global A electrical architecture, which include the 2010 Camaro, LaCrosse, Equinox, Terrain and SRX. Each method has a specific role. The following definitions are intended to provide an overview of these methods.
The purpose of the security code is to protect the vehicle's security information against tampering.
The security code is a random code, unique to each vehicle, generated at the vehicle assembly plant. The assembly plant stores the security code and the corresponding VIN for each vehicle. A correct security code match is required to allow specific vehicle theft deterrent functions to be performed. An example of this function is the learning of new key fobs to the vehicle.
Environmental ID
The purpose of the Environmental ID is to increase the time and complexity involved in attempting a vehicle theft by swapping control modules.
The Vehicle Theft Deterrent Feature provides the capability to detect if modules have been substituted, indicating a potential theft situation, and will not allow continued running of the engine in that case. The Immobilizer Master (BCM) identifies itself to the Vehicle Identification Devices (IPC, HVAC, BCM, ECM, SDM and SCLCM - if equipped). If the Immobilizer Master is recognized as correct, the Vehicle Identification Devices respond with specific environment identification.
The Immobilizer Master is required to receive a certain number of correct environment identifications in order to authorize the powertrain control module to allow normal engine operation. If the correct number is not received, even after retry, engine pre-release will expire and the engine will start, and then stall. The Security MIL and/or Driver Information Center will display an indication when the Vehicle Environment Identification check has not been successful.
The purpose of Seed and Key is to protect certain control modules from unauthorized reprogramming when they are outside of the assembly plant environment.
Each control module that implements Seed and Key is manufactured with a unique seed value and a corresponding key value stored in memory. The seed is a value that is reported to a reprogramming tool. The reprogramming tool must know the matching key value to unlock the control module so that it can be programmed. The reprogramming tool then sends the matching key to the control module. If the key sent from the tool matches the key contained in the control module, then the tool is granted access to reprogram the control module or to send commands to put it in a re-learn mode for Vehicle Theft Deterrent.
There is no way to read the key value out of a control module. Secured functions can be performed only after successfully determining the key and sending it to the control module. If two incorrect keys are sent, the control module will not respond to another request for seed within 10 seconds. In addition, a control module will not respond to a request for seed within 10 seconds of the ignition turned on.
TIP: Importantly, seed and key and security code are not the same, and serve different purposes.
Security Components
These modules involved in vehicle security are shown in the accompanying schematic. (Fig. 1)
· Body Control Module (BCM)
· Engine Control Module (ECM)
· Instrument Panel Control Module (IPC)
· Heating, Ventilation and Air Conditioning Module (HVAC)
· Electronic Brake Control Module (EBCM)
· Sensing and Diagnostic Module (SDM)
· Steering Column Lock Control Module (SCLCM)
Radio
Although the radio is not part of the vehicle theft prevention system, the radio does have its own theft protection. The radio theft deterrent system is intended to disable or limit radio functionality if incorrect vehicle information is received by the radio.
The radio disables functionality if the VIN information received by the radio does not match the VIN information that has been learned by the radio. A possible cause of incorrect VIN information could be that the radio was originally installed in another vehicle. The radio in Global A vehicles cannot be swapped due to the inability to alter the VIN in a radio once it has been learned.
- Thanks to Jeff Flood, Mark Haning and Kevin Fondaw
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