AWX 1.9Pd limp mode at 60 degree Centigrade

[Chopperman]

My 2001 AWX PD 1.9 with 95,000 miles goes into limp mode at 60 degrees C.
I have check the fuel pump in the tank. New fuel filter. Taken the turbo apart, nice and clean for a diesel. The turbo works throughout the Rev ranges as it should but only below 60 c.
I have put the MAP & MAF sensor on from my other AWX but still the same.
No fault codes.
Now, when I put an immobilised and chipped ECU on it, it goes as it should. Lumpy but ok, though it does kinda go into semi limp mode when it gets 90c for a short while then normal. Any ideas?
As a note, the electric fan runs.
I also did a throttle reset using my VAG007 OB11 tonight. Bloody hell. It went like a lunatic!