IF one was the devious sort... you could remove the engine (spark plug cover) and mist some water all over that area - with the engine running. That might be enough to make an SES or ECL come one and give you the needed code to have all the coil packs replaced.
Btw... IF you get your dealer to replace all the coil packs you might want to twist their arms some for new plugs while they are at it and new injectors. Replacing all three items will make your car idle and drive like a new car.
