Afternoon All & thank you in advance for any comments on what my issue could be.

I have an Smax with the same engine as the 2011 ST so hoping some ST owners can shed light on this issue? 🤞

 

The car currently does not create boost (or cannot due to a control system)

I have taken the car to two different garages and they have not been able to diagnose the cause.

Boost control solenoid has been bench tested and works correctly.

Turbo actuator has been manually tested and works as it should.

A vacuum leak smoke test has been done in various places and no leaks were found.

The garage does not think that the turbo is the issue.

 

The garage has informed me that there seems to be no vacuum when the engine is running to control the turbo actuator. I am not familiar with the nitty gritty of this particular engine however have a good general understanding of most bits.

 

Does anybody know if there is more than one boost control solenoid?

Where is the vacuum pump on this engine?

 

I would really appreciate any info you may have on this as its our only car and becoming rather urgent to fix!

Vehicle is on 125k btw.

On 5/1/2025 at 11:48 PM, JamesSvr6 said:

Afternoon All & thank you in advance for any comments on what my issue could be.

I have an Smax with the same engine as the 2011 ST so hoping some ST owners can shed light on this issue? 🤞

 

The car currently does not create boost (or cannot due to a control system)

I have taken the car to two different garages and they have not been able to diagnose the cause.

Boost control solenoid has been bench tested and works correctly.

Turbo actuator has been manually tested and works as it should.

A vacuum leak smoke test has been done in various places and no leaks were found.

The garage does not think that the turbo is the issue.

 

The garage has informed me that there seems to be no vacuum when the engine is running to control the turbo actuator. I am not familiar with the nitty gritty of this particular engine however have a good general understanding of most bits.

 

Does anybody know if there is more than one boost control solenoid?

Where is the vacuum pump on this engine?

 

I would really appreciate any info you may have on this as its our only car and becoming rather urgent to fix!

Vehicle is on 125k btw.

brawl stars online

Hello, normally only one boost control solenoid (BCS/N75 valve) is used for turbo control. Moreover, on the 2.0 TDCi PSA/Peugeot-derived diesel, the vacuum pump is mounted on the rear or side of the cylinder head. It is mechanically driven by the camshaft. You’ll see one or two vacuum lines coming from the pump — one to the brake booster and one into the turbo vacuum system.

On 5/1/2025 at 5:48 PM, JamesSvr6 said:

The garage has informed me that there seems to be no vacuum when the engine is running to control the turbo actuator. I am not familiar with the nitty gritty of this particular engine however have a good general understanding of most bits.

I can only recommend to trace the vac hose back from the turbo.

You will eventually come to the turbo vac feed point, pump or solenoid

Afternoon,

I ended up limping the car to my friends garage 100 miles away.

 

He tested all of the vacuum system and found all parts working as they should but said he couldn't hear the turbo spooling even though the previous garage said they could.

He noticed an exhaust manifold leak and said as the turbo control side all seems to be working the next step would be removing the turbo to see if it spins and if it needs replacing the exhaust manifold leak would be fixed as well. He removed the turbo and part of the inside of the cast exhaust manifold had cracked and broken away which then got sucked into the turbo seizing it. 

Ended up having a new turbo, gaskets, turbo feed and return lines and oil change, filters etc for the warranty.

Unfortunately while under the car he noticed a leak from the gearbox, which meant removing it and fitting a new seal.

An expensive fix even with mates rates

 

Unfortunately 4 months later and now the car is throwing the code P0258 'B' which is fuelling related.

 

This car is the gift that keeps on giving......

Focus 1.0 similar problem.

Changed turbine (very expensive), but it wasn't fixed.

Found out it was the N75 solenoid.