Some of you said this code might be appearing in low temperatures due to a sensor problem.

I have a diesel 95hp T300 too and this code poped out during last winter (I live in a warm coast area in Spain). At that time my car would sleep in the street so temperature could get lower than 5º during the night which might be cold enough.

Also, I noted down this code appeared while I was having a trip in a very cold zone of inland Spain during that winter.