Peugeot 406 coupe hdi, mapped and lowered

[Poodle]

Turbo pressure is usually a sticky actuator or boost leak on these iirc. The pre-heating relay is just that, same as on the 306 - four glowies in a unit that plugs into the coolant circuit. Don't know where the relay is, but it's unecessary and won't bring up the eml. Helps the car warm up quicker though, should improve mpg a bit on short journeys and mean your windscreen clears quicker.