Zafira diesel 2002 engine management light limp home mode re-occuring?

I have a 02 reg 2 ltr diesel zafira and during driving the radiator light and the engine management light comes on. The the revs counter drops to nil, the turbo ceases to function and the engine sounds very very jumpy. I seems to recover on it own (the lights on the dash go out) and turbo comes back on (including revs counter) but it happens again and come back on again. Very confused about whats causing this as the OBDII machine has no codes. Is it a case of plugging in the OBD machine while its doing this or has someone else managed to cure this? Oil level is fine and radiator level is fine. Passed it MOT with flying colors recently.

This can happen anything up to three times a day and sometimes just once a day.

Anyone got any ideas?

hsingh125 at hotmail dot com

Dave