alfredbraun1

Mercedes GT Roadster Hybrid Fuel Consumption Issue

My 2020 Mercedes GT Roadster Hybrid has increased fuel consumption, the check engine light is on, and there's a hissing sound on acceleration. I suspect a leak in the air intake system after the mass airflow sensor but before the turbocharger. What should I check?

4 comment(s)

I had similar symptoms on my 2018 Volvo XC90 petrol engine: elevated fuel economy, check engine light, and a hissing sound. It turned out to be a cracked vacuum hose connected to the turbocharger. Have you checked the hoses for visual damage? Even a small split can cause issues.

Thanks for the reply. Can you share how you pinpointed the leak? Did you use any special equipment or techniques beyond visual inspection to find the compromised vacuum hose location? More details would help me diagnose my Mercedes faster.

I initially tried a visual inspection, but the crack wasn't obvious. I took my Volvo to a shop, and they used a smoke test. They introduced smoke into the intake system and looked for where it escaped, showing the leak's location. Given the complexity of modern intake systems, a professional diagnosis might be best.

Thanks for the advice. I did similar checks and found a cracked intake hose after the mass airflow sensor. The part cost around 100€. Your experience really helped me resolve this quickly, I appreciate it.

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