L322 in limp mode, no fault codes

I own 2011, L322, 4.4 tdv8, With an illuminated dash, yes that famous engine management light + DPF is on and I'm stuck in limp mode.
I have taken it to my local mechanic who has carried out a diagnostics check using his snap-on equipment.
There was no fault codes showing, so he cleared the system and turned off the engine management light.
My beloved Range Rover was back driving normal for a few miles when the both the engine management and DPF lights came back on with me back driving in Limp mode.

Any ideas of suggestions would be appreciated.

DPF blocked??

Hi bazbar from what I have read about dpf's is if you do a lot of small miles the dpf clogs up ie doesn't get hot enough to burn off the soot, so at least once a month you need to take it on a good run preferbly m/way at 70mph to burn off the soot for 20 mins to 30 mins.
I have no experience only what I have read.
hope it helps.
greg

If the engine management light is on then there must be a stored code. It sounds like the mechanic's Snap On tool didn't read the car fully.