Recurring issue only when slowing down from speed (50/60mph plus) to stop/near stop e.g. at a roundabout, and never around town at 30-40mph, though once it starts problem will then continue around town too.

It only happens once engine is warm and turning off engine resets the problem after about 3-4 mins. However if repeat slowing down from speed on same journey (e.g. still warm and I have just waited briefly to reset problem) it will reoccur quite quickly with same driving behaviour. Seems to be linked with deccelerating from speed as approaching roundabout from driving at 40mph won't cause problem whereas slowing to roundabout from 70 will.

Engine seems to go into limp mode and there is very little power or acceleration. Can get to 70+ with a downhill slope/slip road and stay there on motorway/dual carriageway but then down to max 50 with a mild uphill slope. Will not rev above 2800/3000 revs and engine sounds more like an old standard diesel than a turbo diesel when trying to rev up in lower gears. Only once when this has occurred has a warning light or code come up and then it was 'turbo pressure sensor circuit high'. Most times no light or code.

The above means it's basically long journeys it happens on, which can be quite annoying when you have to face an hour plus of limping!

Any help directing my mechanic what to look at would be greatly appreciated as there seems to be lots of similar but different problem around!

Hi,

I had the same problem with my Cmax before, the problem was that my car had a dirty throttle body and a very dirty air filter. Open the bonnet and see the throttle body and air filter they are easy to clean specially for the Cmax without the need to see the mechanic.

Here is a link for the throttle body just copy and paste the link :

This is a link for the air filter.

after cleaning those my car was fine.

After cleaning those see if it fixes it. if it does not and the problem is still there you may as well go to the mechanic because sometimes other parts of the engine needs replacing or cleaning.

Hi

thanks for your reply - I don't think it is this because the air filter was changed at the service without any difference (unless there is another problem that is clogging up the filter really quickly) and I am fairly certain he looked at the throttle body for me too, although I may mnisremember that!

As I say the problem is hard get him to look at when it is actually occuring, as it only happens on long journeys which are most often at the weekend visiting family, so can't run it round to him. It clears itself when engine is off and completely when cooled.