Hi all,
only getting 1/4 boost, with engine management light and esp that wont turn off.
checked codes and got following
p0075
p0076
p0078
p0079
p0102
p0245
p0458
they all look to be sensors that are low.
I have changed maf, and no noise so thinking not filter housing, it could be boost solenoid but would this cause all codes or any ideas of electrical issues which could be the cause?
Thanks in advance for any help
Kev.

 

boost pipe jubilee rotted and popped off?

 

You have 4 different codes for 1 part - the Intake Valve Control Solenoid Circuit. Sometimes it's too low, some times it's too high.
That makes me think you have a wiring defect with the signal wire sometimes shorting with ground and sometimes with Battery voltage.
The other 3 codes are all a signal too low.
Maybe there's a loose connection in a connector and/or resistance somewhere where all these wires are in a common connector.

 

Thanks for the suggestion, all hoses/ pipes seem secure, a smoke test may prove otherwise though.

 

I was thinking electrical myself, is the intake valve control solenoid otherwise known as the boost solenoid, as part looks the same?
on another forum a thread has the same codes and traced it to oil temp sensor on oil filter housing, changed housing and all ok.

 

No, the intake valve control solenoid is NOT the boost solenoid.
This solenoid controls the position of the inlet camshaft on engines with VVT (Variable Valve Timing).

 

Thats what I thought, but when I look online all I get are boost control solenoids, does snyone have a part no. for the intake valve control solenoid?

 

Found a fuse blown under bonnet fuse 35-powertrain control module, sensors, solenoids and crank heater element.
changed fuse and cleared codes started up and no codes idled perfectly and revved good, until i drove it and popped the fuse again!!

 

Short circuit probably in a connector.
I have seen this (DTC's on both signal too low and signal too high) several times, although be it with other sensors.

 

It wsn't on a Focus ST Just a normal shopping model Zetec or whatever, but had a similar fault kept blowing a fuse, found loom was shorted where the loom passes around the bellhousing. under the inlet manifold.