PatNeuMan

SL Generator Fault Symptoms and Replacement

My 2004 Mercedes SL with a gasoline engine is giving me fits. I'm experiencing reduced engine power and a warning light is illuminated. It struggles to start, and the lights are weak and flicker. The error memory shows a fault with the generator. Could a defective generator really cause all of these symptoms? I am seeing a voltage drop and am worried the car won't start completely.

4 comment(s)

Sounds familiar. I had similar issues with my SL. Weak lights, struggling to start... classic signs. Have you checked the serpentine belt? If that's loose or damaged, it can affect the alternator issue. That said, your symptoms do point towards a failing generator. Did you try testing the starter motor?

The serpentine belt looks fine, no obvious damage or looseness. I haven't tested the starter motor specifically, but it seems to be working, albeit weakly, since the engine does eventually turn over. When you say 'alternator issue', do you mean the whole generator needed replacing, or was it just a component like the voltage regulator?

In my case, it was the whole generator. The shop told me the internal components were shot. Honestly, diagnosing those things can be tricky, and you can end up chasing your tail. Given your symptoms and the error code, I'd say bite the bullet and get the generator replaced. It’s not worth getting stranded. My advice is to take it to a professional.

Appreciate the input. Based on your experience and the symptoms, I've decided to go ahead with the generator replacement. The workshop quoted me 960€ including labor. Hopefully, this resolves the voltage drop and starting issues once and for all. Thanks for confirming my suspicions.

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