Have suggested that to him before... there are two, one in the cat and one in the dpf. when they fail they put a D5 into a restricted power mode (not the normal limp mode) where you ave no lights or messages on he dash and it wont rev past about 3k but you have good power otherwise. Generic code readers will report this as "temperature sensor bank a" or similar, VIDA as always will tell you exactly what is wrong and even give you a diagram as to where it is...

I had a similar problem on my s80 D5 on a 06 plate.

Cleaned the egr and the right angled egr pipe and all has been well since.

Any update from taxi_driver?

This seems to be a relatively common problem. The rear one on my XC90 was replaced under warranty and the dealer told me that it was a known problem that particularly affected 2010 models (faulty batch of sensors?); on mine I had a warning light but no effect on power.
We recently had the same problem on my son’s 59 reg XC70, but in his case, he had the exact power loss symptoms as the OP. We changed the rear sensor and all is back to normal.

The last one I did was on a '59 plate V50 D5 - no power above 2,800 rpm but no lights/warnings.

Hi there,

Can anyone help with the part number? This seems like the issue with my mothers 2012 xc70.

Much appreciated.

I had that problem also, compounded by the dealer snapping the sensor trying to get it out, then they didn't have the correct tap to drill it out, then they had to take it off to drill it out, resulted in a bill for £300. They did however also change a sensor on the inlet side of the engine also. Had no lights on dash just symptoms of the turbo being switched off momentarily.
As I was towing the caravan at the time looked a real boy racer as the front tyres lit up when the power came back in.

Paul.