Mercedes R Klasse Starting Problem Solved

My 2007 Mercedes R Klasse with a diesel engine, odometer at 220998 km, is having starting issues. Sometimes it briefly starts, sputters, and dies. Diagnostics show an immobilizer error. I suspect a faulty key programming is causing the anti-theft to engage incorrectly. I've read about immobilizer bypasses. Should I explore that, or is it a deeper electronics or ignition issue?

4 comment(s)

An immobilizer issue can cause those symptoms. If the anti-theft system isn't disengaged, the engine won't run. Have you tried your spare key? Is the key fob battery good?

I only have one key. The battery is new, replaced a few days ago hoping it would fix it. Could the key need reprogramming? Can a standard mechanic do that, or is it dealer-only?

Reprogramming the key is possible. If the car's computer doesn't recognize the key, the immobilizer prevents starting. Get it diagnosed professionally; most workshops can check the immobilizer and key. They can determine if you need a new key or reprogramming. It's complex and best left to experts.

Thanks, I suspected as much. The workshop confirmed the key lost its programming. They reprogrammed it for 45€ and the car starts fine now. Your advice was spot on.

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