louis_scholz1
Seat Leon Diesel engine losing power
Summary of the thread
A 2023 Seat Leon Diesel is experiencing a significant loss of power, a check engine light, and increased fuel consumption. The issue is suspected to be related to a boost pressure control fault, possibly involving the turbo system. A faulty vacuum switching valve is identified as the cause, and replacing it resolves the problem, restoring the car's performance.
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4 comment(s)
louis_scholz1 (community.author)
How can I check the boost controller and intake manifold myself? I'm not super mechanically minded, but I'm willing to have a look before taking it to a garage.
paultiger1
Yeah, poking around might reveal something obvious, but messing with the turbo system without knowing what you're doing can cause more harm than good. If you're seeing reduced engine power and the engine light is on, it's likely the ECU is pulling back the boost to protect the engine. Given the symptoms, especially the poor engine response and higher fuel consumption, I'd say get it checked by a pro. A faulty vacuum switching valve sounds plausible, especially if it's affecting the boost pressure. Turbo lag can also increase.
louis_scholz1 (community.author)
Took it to the shop, and you were spot on! It was a faulty vacuum switching valve. They replaced it, and the car runs like new again. Cost me 140€. Thanks a million for the help!
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SEAT
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LEON
paultiger1
Oh, that sucks! Check engine lights are the worst. Sounds like your turbo's having a rough time. Is it happening all the time or just when you put your foot down? Could be a dodgy boost controller messing things up. Is the intake manifold making weird noises? Compressor surge can sound pretty scary. I had similar issues on my old ride, turned out to be a cracked hose causing a massive vacuum leak.