“My Mercedes Benz refuses to start when I turn the key”
Driving a Mercedes Benz is a great pleasure. Despite this brand’s high quality, though, Mercedes’ can develop problems with or without regular car maintenance. There are a few theories about why your Mercedes refuses to start when you switch the key in the ignition.
Signs of a Car Problem
It is infuriating to slide behind the wheel, turn the key, see dash lights blink, but the engine won’t turn over. When you least expect it, running late on your way to a special event, you try turning the key again. This time, you have enough power to activate accessories like the interior lights, the windshield wipers, and the windows but still no engine.
In many Mercedes models, a relatively minor problem that occurs in its electrical system disables the entire. This might have happened to you.
- Could you turn the ignition key all the way to the start position?
- Did the vehicle lock in Park?
- Did you hear any signs of life whatsoever when you attempt to crank the engine?
Electrical Systems Malfunction in Mercedes Benz
As noted, Mercedes owners share this faulty ignition problem more often than other drivers. This is largely due to its complex electrical systems, and extensive, theft-deterrent features designed to protect your Mercedes Benz. While these systems deliver a flawless performance in good working order, they can cause severe problems when they fail.
The components that you’ll be focusing on here are your car’s keys, its electronic ignition system (EIS), the battery, and some of the sensors connected to the electrical system. Damage, neglect, or even ordinary wear and tear in any of the parts named above can jam your Mercedes’ ignition, rendering it impossible to start the car.
Possible Causes for Your Mercedes Benz Problems
Key Problems: If your Mercedes’ key fob has a dead (or dying) battery, it may not communicate properly with the Electrical Ignition System (EIS). If your model has an IR-equipped key fob, it may need to be reset (see below) to communicate properly.
EIS Problems: If the ignition system itself is to blame, it may have intentionally locked down your car’s engine to prevent theft. This can happen if the EIS is damaged or if it does not recognize your key as valid.
Battery Problems: In many cases, a dying battery will have just enough power left to run
secondary electrical systems but not enough juice to turn the car’s starter motor. In this event, all you’ll need to do is replace the battery.
Sensor Problems: There are multiple components attached to your car’s electrical system that are also connected to the ignition security system. (The crankshaft position sensor is one example.) If these sensors are damaged or disconnected, the car will refuse to start.
Repair Mercedes Benz Electrical Ignition System
As noted above, a battery replacement will frequently solve this problem. To determine whether or not your problem is with the battery — without going to the expense of buying a brand new one — use another car to jump start your Mercedes. If this is successful in getting the engine to start, you’ll know your issue is with the battery.
If you can’t even turn your car’s key to the “start” position, you can be certain that the problem is either the electrical system or the key itself. If you have backup ignition keys, give them a try. You’ll have to get a dealer to help you with a key that isn’t recognized by the EIS. If your keys have an infrared connection (check your owner’s manual) you may be able to fix the problem yourself. Check your owner’s manual.
If the issue is a lost signal between the fob and the EIS, you can force a manual reset by placing the key in the ignition and leaving it for five minutes.
Fixing problems with your Mercedes’ sensor suite is a repair for Desert Oasis Auto Repair. Locating a faulty sensor requires that advanced diagnostic equipment that we use in our shop. Further, Desert Oasis only uses OEM parts from Mercedes-Benz to perform a repair.
