Still having dramas with my 2.7 2007 RRS....engine system fault code coming up as P023D-22 'MANIFOLD ABSOLUTE PRESSURE - TURBOCHARGER BOOST SENSOR A CORRECTION'.....the garage says that a cracked exhaust manifold that they have seen is causing it, but another garage who have worked on more RRS say that they have never seem this and more likely intercooler pipe split or inlet manifold.....anyone else come across this issue????

The garage says that to change the exhaust manifold whole engine needs dropping and not a cheap job!!!

Sounds as if you need to find a different specialist - one where they know what they are talking about.

That code usually means there is either a problem with the turbo (often a seized actuator linkage) or a crack in the intake manifold.

This is what the workshop manual has to say for that code:

Check the intake air system. Check the turbocharger
mechanical condition and operation. Check for DTCs
indicating a listed sensor fault. Rectify as necessary.
Using a data logger function, monitor the
turbocharger actuator position and command the
actuator to 5% pulse width modulated (PWM), then
95% pulse width modulated (PWM) in 5% steps.
Check the results. There should be a smooth curve
between the minimum and maximum values. If not,
install a new turbocharger. Clear the DTCs and test
for normal operation.

Cure for the turbo problem might be as simple as soaking the linkage with penetrating oil or similar and working it back and forth with a length of stiff wire (coathanger or welding rod). Its' a common problem especially with 'school run specials'.

If that is successful then just make sure you give the car a good bootful on a regular basis (but only when engine is thoroughly warm) to help prevent it seizing again.

If it's crack in the intake manifold (diagnose with a smoke test?) then the manifold needs replacing - bit involved but it is NOT a body off job. 2008 MY Java Black TDV8 HSE