Advanced Restraint System - Operational Characteristics
TSB 06-26-801/08/07
RESTRAINT SYSTEM - AIR BAG DEPLOYMENT STRATEGY WITH ADVANCED RESTRAINT SYSTEM
FORD:
2001-2002 Crown Victoria
2002 Taurus
2001-2002 Windstar
2003 Expedition
LINCOLN:
2001 Town Car
2003 Navigator
MERCURY:
2001-2002 Grand Marquis
2002 Sable
ISSUE
This article supersedes TSB 02-17-5 to update the vehicle application and model years. Questions about the operation of the air bag system may occur with normal air bag/pre-tensioner deployment strategies. Example: the passenger air bag may deploy when the driver air bag does not deploy.
ACTION
This TSB is provided as a resource to better understand the system operation and address customer inquiries about the operation of the Advanced Restraint System equipped in these vehicles. Refer to the following Service Information for details.
SERVICE INFORMATION
Advanced Restraint System Overview:
2001-2002 Crown Victoria/Grand Marquis, Windstar, 2003 Expedition/Navigator, 2001 Town Car, and
2002 Taurus/Sable are equipped with the Advanced Restraint System that manages deployment of the driver air bag, front passenger air bag, driver safety belt pretensioner, and the passenger safety belt pretensioner separately. The Advanced Restraint System has the ability to shift the frontal air bag deployment thresholds based on crash severity and whether the safety belt is buckled or not. In some circumstances only the driver airbag or only the passenger airbag may deploy as explained below.
Normal System Operation Example:
The most common example that causes customer questions is one in which the driver is belted, the front passenger seat is unoccupied, and the vehicle experiences a low-to-moderate severity frontal collision. In this scenario, the customer may observe that only the front passenger airbag deploys. Because the driver observes the deployment of a single air bag, the customer may be concerned that the restraint system is not working properly. The customer's concern may be addressed with the understanding that the system independently tailors protection for belted and unbelted occupants.
There are different threshold levels of crash severity that initiate activation of the advanced restraint deployable technologies. Safety belt pretensioners have the lowest activation threshold and may activate without any airbag deployments. The driver and front passenger airbag deployment thresholds for UNBELTED occupants may be the same or slightly higher than the safety belt pretensioner threshold. The driver and front passenger airbag activation thresholds for BELTED occupants have the higher levels.
Given the differing threshold levels for the activation of the safety belt pretensioners and front impact airbags, a number of different deployment scenarios may occur as a result of different combinations of frontal crash seventies and safety belt use. Thus, in the example discussed here (belted driver, unoccupied front passenger seat, low-to-moderate impact severity), the deployment scenario may be one in which the safety belt pretensioner deploys for the BELTED driver while the front passenger airbag deploys for the UNBELTED position. Therefore, deployment of only one of the airbags is not cause for concern but reflects advancement in safety system technology.
WARRANTY STATUS: Information Only
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