Hi all. I’m really hoping someone with any experience with this issue can help me. I purchased a 2014 1.6 diesel Fiesta in September of 2017. After 6 months the car fell into a ‘limp mode’ and it’s never really left it. I’ve spent £100’s of pounds in several different mechanics trying to figure out the issue and the same topic is ‘turbo’ problems comes up in conversation. The diagnostics have always come up with under or over boost failures and have had the sensors replaced in this department. The car seems to always experience this issue in higher weather temperatures usually over 15degrees. Usually the months of March to October it’s a nightmare. I’m currently sitting on 73,000 miles and I usually drive up to 50 - 70 miles a day communing to work and back. The ‘Service Engine’ (spanner) light comes up on the dash whenever the car loses it’s power and has barely any acceleration. I’m wondering if this has happened to anyone before with this model? I am at a dead end and no one can figure out the issue. It’s got to the point of turbo replacement but thought I’d try some forum pages to see if anyone can give me any advice before I make that VERY expensive decision. Could it be a DPF issue? I’m not very experienced with cars what so ever so any advice would be greatly appreciated! Thankyou.

Hi Chloe,

This engine is usually pretty reliable, it's the older 1.6 that had common issues with turbo, DPF, EGR etc.  The only common issue on these 8v engines is injectors but that doesn't sound like your problem.

Have you had any Ford diagnostics done on it at a Ford dealer?  If not, the best thing you can do is get Forscan.  It can find many more fault codes than the generic OBD scanners they use at independent garages.  Can be used with either a laptop or smartphone, wired or wireless.  You don't really have to know anything about cars to use it.  

Adapter can be bought here - https://tunnelrat-electronics.fwscart.com/ELM327/cat4541937_3675533.aspx

If you can do that and post any fault codes on here, we might be able to make a better suggestion of the fault.

 

Do you know exactly which parts have been replaced so far?  I'd guess MAF sensor, MAP sensor and boost solenoid?

Hi there, Thankyou so much for responding. I haven’t been to a Ford dealership themselves just several different independents but I will definitely look into purchasing a Fordscan Thankyou! 
 

So far what I know, I’ve had the boost solenoid replaces last week I believe, it worked for a few days with no issues, in a heatwave and it was perfect however sadly fell back into lymp mode. When I took it back to my mechanic the code read that it was an ‘underboost failure. I’ve had the fuel filter replaced a couple of days ago and had some cleaning solution put in to help? 
I will post some codes once I can get my hands on a fordscan! 
 

if it helps, the car doesn’t perform well when it’s higher temperature or if I’m on the dual carriageway (which includes 2 roundabouts, shifting in and out of gear seems to trigger it usually too) the road is 25-30 mile route to work. It always jumps straight into limp mode if I shift into 5th gear which is a nightmare. 
 

Thankyou again. 

+1 for forscan and tunnel rat, the amount of times I've scanned my car in the last couple of weeks, if I was paying a garage £40 a time, I could've bought a new car. I got the WiFi one, keep it in the glove box, if anything goes wrong, scan on my phone, clear codes and see if any come back. 

It does seem odd that it's so temperature dependant.  There's an intake air temp sensor in the MAF so that seems like a potential suspect if not already replaced.

Underboost can also be caused by a small leak anywhere between the turbo and the MAP sensor, but it should be fairly easy for any garage to find if that was the issue.

Hopefully Forscan can provide us with a more useful code.  

Hi, 

Was there any fix found for this, as I have the same problem and faults which also seems weather dependent. 

Thanks