EIS-Equipped Mercedes Locksmith
619, Curbside

Yes, on most Mercedes through model year 2019. The list of serviceable chassis covers the W204 and W205 C-Class, W212 and W213 E-Class, W221 and W222 S-Class, W164 and W166 GLE, and related platforms from roughly 1998 through 2019. The procedure runs on the Autel IM608 paired to VVDI MB and other EIS-compatible tools: read the Electronic Ignition Switch, pull the security PIN, pair the new key. That work finishes at your address anywhere across San Diego County, no tow. Post-2020 cars on FBS4 or FBS5 require online Xentry server authentication that only opens through dealer-authorized channels, and we check your VIN against that boundary before any appointment goes on the calendar.

KEYLESS-GO is the Mercedes marketing label for the passive proximity entry and push-button start system that first appeared on the 1999 S-Class W220. Antennas placed around the door handles and inside the cabin detect the fob's presence, so the doors unlock and the engine starts without any button press on the fob itself. Programming or replacing a KEYLESS-GO key requires syncing the new fob to the Electronic Ignition Switch module using professional tools that can read and then write the EIS data. There is no owner-side self-programming sequence on any KEYLESS-GO equipped Mercedes, regardless of what any video on the internet suggests.

This is the dominant complaint we get from post-2015 KEYLESS-GO owners in San Diego County, across the C-Class, E-Class, and GLE lineup. The likely causes in order: a low CR2025 or CR2032 in the fob, a weak 12-volt vehicle battery (especially common after summer heat in Santee or El Cajon has worked it over), RF interference from recently-installed cabin electronics, and, less commonly, a failed vehicle antenna or EIS module. First test: hold the fob directly against the start button. If both fobs fail in tandem with fresh batteries, the fault is vehicle-side rather than fob-side. We work through the diagnosis on the call before dispatching.

Mercedes-Benz USA itself sells a key protection plan that covers replacement up to $800 per occurrence, which is the clearest signal of what unprotected dealer pricing looks like. On complex all-keys-lost calls on the newer platforms, that threshold gets cleared regularly once tow and labor stack on. Our pricing for Mercedes EIS-compatible programming on supported model years runs significantly below that figure, covers the blank, the cut, and the on-site programming in a single visit, and requires no tow. See the pricing table above for the figures by key type.

Yes. Every KEYLESS-GO equipped Mercedes carries relay-attack exposure, where two operators use signal amplifiers to extend the fob signal from inside the house out to the car in the driveway. Documented real-world thefts have been reported on the 2018 GLC and the 2015 C63S AMG using this exact method. Mercedes responded by introducing motion sensors in KEYLESS-GO fobs starting with the mid-2019 GLC facelift, which drop the fob into sleep mode after about 20 seconds of inactivity and shut down the relay capture window. For pre-2019 cars, double-pressing the lock button on the fob disables KEYLESS-GO broadcasting. The cheapest defense is a Faraday pouch on the kitchen counter overnight, and it eliminates the attack vector entirely.

EIS is the Electronic Ignition Switch, the module Mercedes uses to store all key data, verify transponders, and authorize the engine to start. Unlike nearly every other brand in the industry, where the key data lives in the body control module, Mercedes centralizes it in the EIS. That means any new key job begins with reading the EIS password before anything else can happen. The password gets extracted via OBD-II using tools like the Autel IM608 or VVDI MB, and it is then used to generate a key file that gets written to the new fob. If the EIS itself has failed (or if the directly-coupled Electronic Steering Lock has failed), the whole programming sequence becomes more involved and may require module replacement before new keys can be paired at all.

Use the chrome release button at the end of the fob to slide the hidden metal blade out. Find the door cylinder in the driver's door handle (some chassis hide it behind a small cover) and unlock manually with the blade. To start: on most E-Class and GLE models, pull the start/stop button outward to expose an ignition slot behind it, insert the blade, and the car starts from there. On C-Class and GLA models, drop the fob into the center console cupholder on the marked key symbol, press the brake, and push start. On S-Class models, the backup fob placement lives in a marked space in the center console or in a dashboard slot, depending on the chassis. The fob's RFID chip communicates passively with no battery power needed once it is positioned correctly.