Hello !,

I have a question about my Ford Fiesta 1.5 TDCi.

I noticed a hose that seems to be detached near the air filter box.

I'm not sure what this hose is called or what its function is. I've attached a photo of the area.

Could someone please help me identify this hose and let me know if it's a serious issue that it's disconnected? Thank you in advance for your help!

It's part of the vacuum pipework.  But I'm not sure of it's function.  I was expecting it to go to a vacuum reservoir but there doesn't appear to be one on the 1.5 TDCI.  It seems to go to a solenoid at the bottom of the picture, with 3 vac pipes to it, unlike a normal turbo or EGR type solenoid.  That may be balancing the amount of vacuum between the inlet and the vac pump, for the turbo solenoid which is the one in the centre of the picture.  That's the best guess I have unless someone else knows what it's for.  As it only goes to the airbox it can't really do much harm just being disconnected.

**EDIT**  On second look, I can't see another solenoid for the EGR cooler bypass.  So it may be for that, although not shown on this picture.

This is the back of a 1.5 TDCI engine.

Blue circle is the EGR cooler bypass actuator.  Orange circle is the mystery solenoid.  Red lines are roughly following the vac pipework.

On 8/5/2024 at 11:37 AM, TomsFocus said:

This is the back of a 1.5 TDCI engine.

Blue circle is the EGR cooler bypass actuator.  Orange circle is the mystery solenoid.  Red lines are roughly following the vac pipework.

Thank you for your detailed explanation. The idea that it might be balancing vacuum between the inlet and the vacuum pump for the turbo solenoid makes sense given the engine's configuration, I was initially unsure and thought it might be a crankcase ventilation hose or PCV (Positive Crankcase Ventilation) line.