Sounds similar to what I've experienced in the last couple of weeks. Check to see if you've got an EOLYS tank underneath the car. Typically these need to be refilled around 36000 miles, altho mine went to 41000 before dropping out to limp home mode. I'm still off the road while the garage reslove all the issues from running with an empty EOLYS tank. This stuff is needed under an EU (yes those bar stewards!) emissions regs and makes liquid gold look as cheap as dishwater - £47+ per litre
. Without it tho, it seems like permanent limp home mode.