Rear emergency tensioning retractor, function - GF91.40-P-4001-04A

Model 163 as of 12/99 

Rear seat belt emergency tensioning retractor, left and right 

In the event of a rear end collision or front end collision (crash with min. actuation stage 1) the restraint system control module (N2/7)  activates the emergency tensioning retractors in the rear of the vehicle. The left rear ETR squib (R12/6) and the right rear ETR squib (R12/7) are simultaneously ignited electrically by the restraint systems control module (N2/7).

The emergency tensioning retractors can only be actuated. once . In the event of a second crash the mechanical protective function of the seat belt is maintained. Without emergency tensioning retractor the reel shaft is locked mechanically by the locking system so that it takes up the entire force of the belt.

The left and right rear emergency tensioning retractors are only activated in the event of a crash when the corresponding seat belts are actually buckled. The switch states of the left rear seat belt buckle and seat belt wear convenience switch (S68/11)  and right rear seat belt buckle and seat belt wear convenience switch (S68/12)  are checked directly by the restraint systems control module (N2/7) 

The emergency tensioning retractors in the rear of the vehicle are not equipped with a belt force limitation feature.