Remapping thoughts.
 

Took on board the comments about tuning boxes. Spoke to a local company that remaps the ECU either on board or removing the ecu and doing it on the bench. The advantage is that they are only 12 miles away and have their own rolling road tuning facility.
There are three levels and the mid range takes the power to 217 BHP and 450Nm torques as they say on Top Gear.

It was suggested that they could eliminate the potential EGR issues by removing it electronically from the system.
I was advised that this would not alter the MOT requirements and it isn't really necessary as it is an EU/US related issue.

I would be interested in thoughts as the cost is £350 and not to be considered lightly.

Is this a game of guess the engine code?

Not sure what you mean, but Volvo seem crash anything other than their own Code reading system.
It does seem that there are a great many codes thrown up by differing issues which do not necessarily point to the real issue.
Cleaning the EGR system on the XC90 does not fill me with glee.

I mean there are 5, 6 and 8 cylinder petrol and diesel engines with specific engine codes and variations through different model years and you've not told us which engine you have.

This was a general question about the principal of remapping and not necessarily about my specific engine which incidently is the 185bhp D5.

You've posted in the specific XC90 technical section.
If it's general question, why not post it in the General Section?

My last 2 cars were remapped and the one prior to that chipped. I do not see issues as long as done by a reputable tuning company and you maintain the car well.

It was an important point as the answer will vary. For example 163 BHP D5 - be careful because the gearbox will struggle. V8 petrol forget it as there is hardly anything to be had. T6 petrol - no one would recommend it.

From May this year a car will fail the MOT if the factory EGR is modified, removed or bypassed. Hard to tell if done electronically but the advise seemed to be suspect.

You

Hi PRC68/Tannaton
Many thanks for the sensible answer as apposed to snarky comments not exactly geared to make people feel welcome.

Nobody likes a smartass particularly another smartass!

That is why I mentioned a reputable tuner, who will know the car well and it's HW limits better. Diesels are quite easy to chip (code is much simpler than that of a turbo petrol), but knowing the limits of the hardware is real important, otherwise thing will break quickly.