2002 Mercedes SLK-Class Owner's Manual - Page 56

Emergency tensioning retractor (ETR) The seat belts are equipped with emergency tensioning retractors. These tensioning retractors are located in each belt's inertia reel and become operationally ready with the key in steering lock position 1 or 2. The emergency tensioning retractors are designed to activate only when the seat belts are fastened during frontal and front-angled impacts and rear 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, roll-overs, certain side impacts, rear collisions or other accidents without sufficient frontal or rear impact forces, the emergency tensioning retractors will not be activated. The driver and passenger will then be protected by the fastened seat belts and inertia reel in the usual manner. For seat belt and emergency tensioning retractor safety guidelines see page 61. Note: The passenger ETR activates only if the passenger seat is occupied. Heavy objects on the 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 treshhold. Restraint systems Instruments and controls Operation Driving Instrument cluster display 53 Practical hints Car care Technical data Index