Mercedes CLK Diesel power loss and check engine light

I own a CLK myself, and your description sounds eerily familiar to an issue I encountered some time ago. Reduced engine power and that illuminated check engine light are certainly unsettling. Did you notice any unusual behavior with the throttle body itself, such as erratic movements or unusual noises? Have you tried checking the connections to the accelerator pedal module? A loose or corroded connection can sometimes mimic a more serious problem. What diagnostic codes are showing when you read the check engine light? This might help narrow down the possibilities.

I appreciate you sharing your experience. I haven't specifically observed any erratic movements or unusual noises from the throttle body, but I will certainly pay closer attention. I haven't checked the connections to the accelerator pedal module myself, as I lack the necessary expertise. I haven't had the opportunity to read the diagnostic codes yet. Could a faulty throttle position sensor also be a potential culprit?

Indeed, a faulty throttle position sensor could contribute to the symptoms you're experiencing. However, given the potential complexity of the issue, and your understandable hesitation to delve into the electronics yourself, I would strongly advise seeking the expertise of a qualified technician. It's better to have a professional diagnose the problem accurately and prevent any further complications. This sounds very similar to the problem I had, and after some diagnostics at the workshop, it indeed turned out to be a defective throttle valve.

I extend my sincere gratitude for your valuable insights and advice. I have taken your recommendation to heart and consulted with a trusted mechanic. After a thorough inspection, it was confirmed that the throttle valve was indeed defective, just as you suspected. The repair cost came to approximately 265€, which, while not insignificant, is a reasonable price for restoring my CLK to its former glory. Thank you once again for your assistance.