Within a month of purchasing the car, it often stalled after long stints of straight driving. This was remedied by the dealer clearing the computer. Since then there have been no problems.
Radiator fan sensor went out after 20,000 kilometers causing the car to approach overheating at very long idles (OK, I know this is not an ecologically savvy thing to do anyway, but...). Dealer replaced this within a few minutes.
I should note that there are only two models of the sedan offered here in Japan and both are fully loaded; the only difference is in the choice engine (2liter or the V6). All models are automatics.
As for the automatic, I find it to be brilliant. It is true that it is not a racer, but it is no slug either and is very smooth in its shifting. I don't realise it is there. It is also very good at down-shifting automatically on down-hills which saves on break wear. I don't feel that I am in a constant process of compensating for its shortcomings, which, in my mind, makes it the best automatic transmission I have ever dealt with.
I am 189 centimeters tall and after my cramped experience in the Mazda 626, sitting in the Peugeot 406 was like slipping into heaven (which is why I bought it). Gone are the pains in my upper back and right knee which pestered me even when not driving.
The downside to this is that being tall, I have the seat all the way back, and from that position, getting out of the car requires my right thigh rubbing on the door pillar. Because the rubber door moulding is so soft, my trousers are constantly getting unsightly black stains. In addition, as the lock catch protrudes, the keys in my pocket catch onto it resulting in all of my trousers having black stains and holes in the pocket area. An unforseen maintenance cost!