Turbo Underboost and Limp Home Mode (1.6 TDCi)

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Hi, recently joined here and created a topic about the upgrade capabilities of the DLD-416/DV6 engine and learnt a lot. Unfortunately, before any of these plans came to fruition, my 2009 Focus has been giving me a heap of confusing problems.

For the last number of months, the car's been entering limp home mode state only when flooring it up a hill. My general opinion on this has always been that she gets like this when she needs an oil/fuel filter change. This normally fixes the problem for at least a couple of months (which is admirable because she's basically my commute and also my only hobby so is driven hard and often).

However, this time limp home mode is happening more frequently, even on the day of the oil/fuel filter change. Having theorised injectors/fuel pressure, she's going to the garage on Monday to get the seals (and hopefully just the seals!) replaced. 

Today, I had a completely different limp home mode, whereas normally she'd just lose power, today I had the fabled 3,000rpm limiter AND a check engine light (the latter of which persisted even after she'd exited limp home mode). OBD reader gives code P0299 - Turbo Underboost and on research I've been told to check basically the whole engine but the general consensus is to order a boost pressure regulator and check the turbo/intercooler pipes for splits. Is this correct? I also hope this means the problem is turbo-only (which hasn't blown or anything) and not to do with the DPF.

Sorry if I'm rambling, I just find that most forums are quite non-descript and I want to document the issue.

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Well, it seems she's come full circle. Turbo's gone, as well as some other parts making it economically unethical to fix. 

Absolutely loved my Focus, saying goodbye to this particular one breaks my heart. If I had all the money in the world, I'd do everything to keep her running. 

RIP, lovely car 😞

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