2002 Mercedes S-Class Owner's Manual - Page 93

Instruments and controls Operation Driving Instrument cluster display 90 Practical hints Car care Technical data Index Restraint systems Emergency tensioning retractor (ETR) The seat belts for the front and rear outer seats are equipped with emergency tensioning retractors. These tensioning retractors are located in each belt's inertia reel and become operationally ready with the electronic key in starter switch position 1 or 2. The emergency tensioning retractors are designed to activate only when the seat belts are fastened during frontal impacts exceeding the first threshold of the SRS and in rear impacts exceeding a preset severity level. They remove slack from the belts in such a way that the seat belts fit more snugly against the body restricting its forward movement as much as possible. In cases of other frontal impacts, angled impacts, rollovers, certain side impacts, or other accidents without sufficient frontal or rear impact forces, the emergency tensioning retractors will not be activated. The driver and passengers will then be protected by the fastened seat belts and inertia reel in the usual manner. Note: The front passenger ETR activates only if the front passenger seat is occupied. Heavy objects on the front passenger seat can appear to the "SRS" to indicate the presence of an occupant in that seat which causes the passenger front airbag to deploy and the ETR to activate in a crash exceeding the appropriate threshold.