Ranger 4WD L4-153 2.5L SOHC VIN C SFI (2001)
Seat Belt Tensioner: Description and Operation
As part of the supplemental restraint system (SRS), the safety belt buckles are equipped with pretensioners. The safety belt buckle pretensioners remove
excess slack from the safety belt webbing. The pretensioners are activated by the restraints control module (RCM) when the module detects a crash event
force exceeding a programmed limit.
The driver and front outboard passenger safety belt buckle and pretensioner are secured to the front seat assembly on the seat track. This allows the front
safety belt buckle end to move with the front seat.
The belt and buckle assembly pretensioner is a pyrotechnic device that removes excess webbing from the safety belt system. The belt and buckle
assembly pretensioner uses the same crash sensor system as the air bag Supplemental Restraint System (SRS). When the belt and buckle assembly
pretensioner deploys, the buckle moves downward, pulling excess webbing from the lap and shoulder safety belts.
If the safety belt buckle and pretensioner assembly is deployed, a new assembly must be installed.
