I thought I'd share this to get it out there. On a recent trip with my new (two week old) D40 the engine went into limp mode when towing a caravan (1300k into the trip). Switch the car off and everything was fine, back up to 100 and straight back into limp mode. After all the usual stuff getting towed and sitting around for days waiting for the car to be fixed I was told it was ready and to come and pick it up. The dealer had followed the advice of Nissan Aus and cleaned all of the vehicles earths etc. and extensively tested the vehicle with no problems. I put the van on the car drove 10k out of town and straight back into limp mode. When I got back to the dealer and the computer was put on the car (note the engine had not been shut down) an error came up with a faulty exhaust sensor. Apparently this error for some reason wasn't being stored in the computer (something to be aware of). Long story short two hours later I was back on the road and drove for the next 6 hours no problems. My own dealer had advised me that this had happened to another vehicle towing a van over Christmas as well.