Peugeot 406 HDI wont rev above 2000 RPM

[MontyC]

My Peugeot 406 HDI engine managment light has come on and now will not rev above 2000ish RPM. It idles fine and starts straight away though, any ideas why would be appriciated?

[S0 What]

On any diesel i allways start with an air and fuel filter unless the MIL is on then i allways start with reading the codes

[davepoth]

I'm going to guess at a loose turbo hose. But if you plug it in you'll know for certain, so do that.

[MontyC]

I have had a loose turbo hose and you can normally hear the leak/whine. It turned out after reading the codes to be the maf sensor, when I removed it you could see a resistor had broken off part of it over time so simple fix.