Hi I have just got home from a fast return journey, total mileage 140miles, from around the M25. Faultless journey until I came off the M25 at J8. About 10 minutes later the car went into limp home mode with the spanner light on and the car would not go over 20 m.p.h.
Stopped the car, turned the ignition off then on again and continued home as normal, with no problem.
Read the engine fault codes which showed:-
P0234-5A Boost pressure control circuit negative deviation.
Where would you think I should look to fix the problem?
My car is a 2004 2.2DTI Vectra.
Thanks for any help.