2000 Mercedes CLK-Class Owner's Manual - Page 63

Supplemental restraint system (SRS) Airbags are intended as a supplement to seat belts. Airbags alone cannot protect as well as airbags plus seat belts in impacts for which the airbags were designed to operate, and do not afford any protection whatsoever in crashes for which the airbags are not designed to deploy. The SRS uses two crash severity levels (thresholds) to activate either the emergency tensioning retractor (ETR) or front airbag or both. Activation depends on the direction and severity of the impact exceeding the preset thresholds and whether the seat belt is fastened. Seat belt fastened • first threshold exceeded: ETR activates • second threshold exceeded: airbag also activates Seat belt not fastened • first threshold exceeded: airbag activates, but not ETR Driver and front passenger systems operate independently of each other. Emergency tensioning retractor (ETR) The seat belts for the front 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 steering lock 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. For seat belt and emergency tensioning retractor safety guidelines see page 69. Restraint systems Instruments and controls Operation Driving Instrument cluster display Practical hints Car care Technical data 63 Index