Isn't Denso part of Toyota? I thought they make all their electrical components............
Yes, Denso is part of the Toyota group.
Denso is owned by Toyota/Lexus.Back to the point about a water temp sensor problem,you would normally have the orange engine man.light on if this was the case,the computor reads all the sensors all the time and would flag up a fault and put the light on.Around 20-25 m.p.g is around right for a rx300 for town driving.