PEUGEOT BOXER VAN KEY CODE & OVERHEATING PROBLEM

Overheating, first, is the coolant leaking, or is the level staying constant? Also is there undue pressure in the rad? Is the rad getting hot? If not then you have a sticking thermostat. In fact that would be the first thing to change as it is the cheapest and easiest. The other possibility is a head gasket problem, but check the thermostat first. Also you might have a blockage in the rad, worth flushing it out if you can. Easily done with a hose. The key has a transducer chip in it, and this is read by a sensor in the ignition switch. For some reason yours is having problems. Do you have a spare key? If so is that the same? When you have this fault, does the starter turn , but the engine doesn't fire, or is everything dead? If the starter turns then the key code is only controlling the cut-off solenoid in the fuel pump. It would be possible I suppose to wire in a manual override for this in the shape of a toggle switch in the cab. You would need a switch as otherwise you would not be able to stop the engine.