Second Hand Mercedes-Benz CLS Seat Belt Pretensioner

Yes, all generations of the Mercedes-Benz CLS are fitted with seat belt pretensioners as standard — they are a core part of the passive safety system and fire alongside the airbags in a collision to lock the belt tight. The CLS has always been a premium model, so this safety equipment was never an optional extra; every variant, regardless of engine or trim, will have them. If your pretensioner has fired after an accident, it will need replacing as it is a single-use device.

These sit in different generations: the first-generation CLS (W219) ran from 2004 to 2010, while the second-generation CLS (W218) ran from 2011 onwards, making a straight swap across that 2010–2011 boundary very unlikely. The mounting points, belt architecture and SRS system changed between generations, so a W219 pretensioner will generally not transfer to a W218. Always confirm compatibility with the breaker using your exact registration number before purchasing.

The CLS was offered in various specification levels — such as SE, AMG Sport and AMG Line on the W218 — and while interior trim and seat style can vary between these, the underlying seat belt pretensioner design may also differ if seat or belt anchor configurations changed. Because pretensioner variants are not always straightforward to confirm from spec alone, you should give the breaker your full registration and ask them to match the part to your specific trim. Never assume a pretensioner from a different trim level is an identical fit.

Yes, side matters — nearside (NS, left-hand side, kerb side) and offside (OS, right-hand side, driver's side in a UK right-hand-drive car) pretensioners are handed parts and are not interchangeable. When requesting a quote from a breaker, always specify whether you need the NS or OS unit, and also the row (front or rear) if applicable. Getting this wrong means the part will not fit correctly, which is a serious safety concern.

Seat belt pretensioners are safety-critical components that work in conjunction with the airbag and SRS system, and incorrect fitting or coding can mean the system fails to protect you in a collision. We strongly recommend having the part fitted and the SRS system checked by a qualified technician, who will also confirm there are no fault codes stored after installation. This is not a job to cut corners on, as a poorly fitted pretensioner offers no protection.

The second-generation CLS (W218) received a facelift in 2014, and while the overall body structure remained the same, interior and trim updates at a facelift can sometimes alter belt or seat anchor configurations in ways that affect pretensioner compatibility. Because pretensioner variants are listed as something to confirm rather than assume, you should check the part number from your existing unit and ask the breaker to verify it against the donor vehicle's registration. Do not assume a pre-facelift and post-facelift W218 pretensioner are identical without that confirmation.