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Mercedes CLK immobilizer problem

My 2010 Mercedes CLK with a gasoline engine has an immobilizer issue. The engine sometimes starts briefly then stops. Diagnostics show an immobilizer malfunction, likely from incorrect key programming. What are possible fixes, like key programming or immobilizer bypass? Can the security light flashes help diagnose the fault? The key signal seems weak, and I suspect the ignition control module.

4 comment(s)

I had similar symptoms with my Mercedes C-Class. The engine would sputter and die, and the security light flashed. I suspected a faulty fuel pump relay or crankshaft position sensor. Check the battery voltage, as low voltage can cause immobilizer issues. Before considering an immobilizer bypass, make sure the key transmits properly. My issue was a corroded connection in the ignition switch. I was stranded for hours!

Regarding your C-Class, can you explain the corrosion in the ignition switch? Did you fix it yourself, or did you need a professional? Did diagnostics show error codes pointing to the ignition switch, or was it a process of elimination?

The corrosion was minimal but disrupted the signal. I tried cleaning it, but I lacked the tools and expertise. A Mercedes-Benz workshop found the problem quickly with their diagnostic equipment. They advised against immobilizer bypass due to security risks and insurance issues. A workshop visit might save you the trouble I had.

Thanks for the advice. A technician confirmed faulty key programming. Re-programming the key fixed it. The cost was 45€. Thank you for guiding me away from the immobilizer bypass.

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