Benz Tips · SteeringMercedes won't start? Check the steering lock

What the steering lock does

The electronic steering lock (ESL, or ELV from the German Elektrische Lenkradverriegelung) is a small motorized lock built into the steering column. When the car is off, it slides a metal bolt into the column so the steering wheel can't turn. It's an anti-theft deadbolt.

It's also a gatekeeper for the whole car. Every time you put the key in or press Start, a quick digital handshake happens:

1. The key talks to the EIS, the electronic ignition switch.
2. If the key is approved, the EIS tells the steering lock to unlock.
3. A tiny motor inside the lock pulls the metal bolt out of the column. That's the short “zip” you hear when you put the key in.
4. The steering lock reports back that the wheel is fully unlocked. Only then is the engine allowed to crank.

Which Mercedes models have this problem

Elite Benz replaces steering locks on these cars all the time, and we've gotten the job down to a science.

Signs your steering lock is failing

A steering lock usually warns you before it quits. Listen when you put the key in: you normally hear the lock “zip” as it unlocks. As the lock ages, that sound gets weaker and weaker until you almost can't hear it. That's when it starts to fail.

While it's failing

• Random no-starts. The car was fine yesterday. Today you go out and it won't start. After playing with it for a while, it starts.
• The zip sound is faint or missing.

When it has failed

• The car won't start at all and leaves you stranded.
• Turn the key to accessory: the dash shows the mileage and backlight, but the other warning lights don't come on.
• On some models the key won't turn.
• The steering wheel stays locked.

We watch for this during your yearly service, so we can catch it early, before it strands you, and you can plan for the cost.

Not every no-start is the steering lock

Here's the part many owners don't hear: on the C-Class especially, it's common to be told you need a steering lock when the real problem is water. A clogged sunroof drain lets water into the car, and it shorts out electrical parts under the carpet. The symptoms look almost the same.

The key can fool you too. A failing key and a failing steering lock act very much alike, so many shops start by replacing the key and hope that fixes it. Without the right test equipment and Mercedes information, it's a guess.

• We test the key to make sure it hasn't failed.
• We check for water intrusion and damage to the electrical parts under the carpet.
• If we find a problem there, we tell you first, before we touch the steering lock, so you don't spend money on the wrong part.

Elite Benz uses licensed MBUSA XENTRY diagnostics, the same factory system the dealer uses, with full access to the Mercedes security system. A steering lock can sometimes be diagnosed in a parking lot, but we recommend letting us look at it in the shop.

Stranded? Tow it, don't trick it

If your Mercedes won't start and you suspect the steering lock, have it towed to us. Skip the YouTube tricks that try to jump or bypass the steering lock to get the car started. They can make the problem worse. Call us first, especially if the car won't go into neutral.

A TRP part: why we need your license and registration

Mercedes-Benz classifies the steering lock as a TRP (a theft-relevant part). TRP parts are parts that could be used to steal a car or give it a new identity, so Mercedes only releases them to verified owners through registered vehicle security professionals.

• To order your steering lock we need your driver's license and current vehicle registration, with names that match.
• The part is ordered from Mercedes-Benz for your car, and we program it with XENTRY.
• Your key and the ignition switch (EIS) are TRP parts too. That's why they all have to agree with each other.

Steering lock emulators: why we say avoid them

Some aftermarket shops and online parts sellers offer a lower-priced steering lock emulator. It's a box that replaces the steering lock and bypasses it and the Mercedes security system entirely.

• Emulators often cause random no-starts. The way they're installed and programmed isn't up to Mercedes standards.
• Because they bypass security, they can upset the signal the key sends to unlock the engine computer.
• Sellers often push an aftermarket key or aftermarket EIS with them, because that's sometimes the only way the emulator works. Avoid that whole setup. (Here's why aftermarket keys cause trouble.)

Already have an emulator?

If your car has an emulator and is having random no-starts, we can usually remove it and install a factory steering lock, and the key catches up to the code that lets the car start. In some cases the emulator has corrupted the software, and we also need to order a new factory key so the key and car are back on the same code sequence Mercedes uses on DAS 3 and DAS 4 cars.

How we replace a Mercedes steering lock

It's a more invasive job than most people expect, because the lock sits inside the steering column:

1. Remove the steering wheel and airbag.
2. Remove the turn signal and shift lever assembly and the lower dash panel.
3. Take the steering column out of the car.
4. Drill out the old steering lock, which is locked in place.
5. Install the new factory steering lock.
6. Do the first start-up and coding with XENTRY, clear the codes, and test everything.

From ordering the part to handing you the keys, it usually takes about 2–3 days.

While it's apart: small fixes, no extra labor

With the steering wheel and column out, a few small things are easy to replace at the same time. You pay only for the parts. There's no additional labor charge.

• Steering wheel buttons that are peeling or worn.
• Chrome trim around the airbag.
• The cover behind the steering wheel, under the dash. On older cars it gets brittle and usually breaks when it comes off.

Little cosmetic fixes like these make a big difference every time you get in the car. Many shops won't offer them. Ask us when you drop it off.

What a steering lock repair costs

Optional extras while it's apart (buttons, chrome trim, the cover behind the wheel) are the cost of the parts only. We confirm everything with you before we order.

Common questions