Why Does My Mercedes Not Turn Over When I Turn the Key?

Driving a Mercedes is an exhilarating experience, and the brand’s quality is second to none. However, problems can arise even with regular maintenance and care. If your Mercedes is not turning over when you turn the key in the ignition, it’s time to call for help!

Check The Battery Connections

First, check your battery level. If it’s low, you might need a new one.

If your battery is ok, but the engine won’t start, it could be because of a bad Electronic Ignition Switch (EIS). You’ll need to get one installed before you can get the car running again.

You might also need to replace your transponder coil wires if they’re detached and stuck in the wrong position. This is a common problem that can cause the key to unlock and work but not turn over the engine.

It’s best to take it to a trusted mechanic for inspection and repair. Otherwise, you might end up with a major mechanical issue that could make it impossible for you to drive the car at all!

Bad Steering Wheel

Another reason why your Mercedes may not start is because of a faulty steering wheel. If this is the case, you need to call for roadside assistance so that you can be towed to a reputable repair shop.

Your steering wheel might be locked up, which is a common issue that Mercedes drivers face. This can happen for a number of reasons, and you need to contact a technician for inspection and repair as soon as possible.

Once you’ve ruled out all of the other causes of a faulty steering wheel, it’s time to try and get your car started again. This might be as simple as a stuck ignition key or it might be more complex, such as an EIS module that needs to be replaced.

Clean The Keyhole

You might want to clean the EIS keyhole with a dry cloth, but be careful not to use liquid in order to do so. You should also check the fuses to make sure that they’re not blown.

If the key is jammed, you can clean the jam using a spray lubricant. Some mechanics recommend using silicon or graphite-based lubricants, which will dispel any debris that has built up inside the ignition cylinder.

When you’re done cleaning the ignition cylinder, you can insert the key and see if it will turn over. Be sure to shake the key when you’re done to ensure that it’s fully inserted into the ignition.

Replace The Battery

The most likely reason that your Mercedes won’t start is because of a dead battery. The battery is the main power source for your vehicle, and it supplies the CAN contact between the N73 Electronic Ignition Switch (EIS) control module and the Smart Key remote.

A faulty battery is the most common cause of a “Mercedes turn key nothing happens” situation, but there are several other issues that you might need to look into before you settle on this solution.

You might also have a faulty Drive Authorization System, or DAS, which checks your drive authorization each and every time you insert the key into the ignition to start your vehicle. This is a security feature that was introduced back in 1996 and has since undergone many upgrades.