I am reaching out because I am experiencing a recurring issue with my Focus 1.5 diesel engine ST-Line. When I accelerate, I receive a pop-up notification stating ‘engine service now’, which then causes my car to lose power while I am driving on the motorway. 

The pop-up notification disappears after I restart the engine.

The problem persists. I have taken my car to a mechanic who suggested that it could be a turbo issue. After further inspection, they recommended replacing the turbo solenoid; however, this has unfortunately not resolved the issue.

If you or anyone you know has encountered a similar problem or can provide suggestions on how to address this issue, I would greatly appreciate your input. 

I am becoming more and more frustrated with the term "Insert name here suggested that..."
Whilst diagnosis is a combination of art and mainly science, there should be investigation with results, evidence, reasoning, justification behind any "suggestion" as evidenced by:
https://intelligentauto.co.uk/services/advanced-diagnostics/

Ask any professional if they will promise:
"If we replace a part and it doesn’t resolve the issue you were experiencing, you won’t be charged for that part."
Otherwise they are just guessing (at your cost)

Reading the codes when the fault is present using Forscan (some basic scanners don't pick up all Ford specific codes) is the starting point for a discussion and investigating live data and a structured plan as above.
For about £30 you can get the lead (V-Linker) and do that yourself to be able to start a dialogue  even if you can't do the work yourself.
Obviously, if you tell them to do something, it's at your risk and cost  but being able to discuss on a similar level based on data is better for your wallet?
Or you can come back here with the full story, codes and get "suggestions" but remember we are at a very long distance so that still isn't ideal but it may be better than continuing to change parts with no real justification (end of rant!)

4 hours ago, Yellows23 said:

I have taken my car to a mechanic who suggested that it could be a turbo issue.

This sounds like another guessing game !!! 🎉🎉

I love these games when we get to have a guess at what might be wrong and Dan @Yellows23 gets to pay the bill even if we guess wrong 🤣

So how to find the fault and fix the car. You can start by doing the diagnostic work yourself using FORScan, or take the car to a Ford dealer who have the diagnostic equipment. Using the Ford dealer for diagnostics doesn't mean you have to get them to do the repair.

Hi,

I am having exactly the same issue, Replaced turbo and selenoid valve - yet same code appearing. Did you ever find out what the issue was?

i had this same problem, and one other problem i had was i had to drop a gear if i was going up a hill.
now i am not saying this could be the fix to your problem but it did fix mine.
the part you could try changing is
https://www.amazon.co.uk/dp/B0G399RHS4?ref=ppx_yo2ov_dt_b_fed_asin_title
i found this fix by accident and for the price its well worth a go as it only takes a few minutes and its simple to do.
just make sure the part number will fit your car, make sure you clean out the old broken part and last watch a few videos of where and how to change.

hope this helps , billiybob