You get the lightshow because Subaru made a design decision to make a big lightshow as an attention-getter, starting with the 2010 models. Too many people were simply ignoring the lone check-engine light.
The car is illuminating the check-engine light (and thus all the others) because there are a lot of sensors below your self-imposed waterline. Not all of them are waterproof, and in some cases they simply can't work underwater. Example- a catalytic converter simply cannot maintain normal operating temperature when submerged. There isn't enough waste heat to sustain the reaction when it is cooled by water from the outside. So even without water intrusion into the electrical system, the car is being pushed outside its normal operating parameters and it's completely fair to expect a diagnostic reaction. It's just annoying because the display behavior has been cranked up.
It's theoretically possible that they could put yet another sensor under there to determine if the car was in deep water, then use its data to suppress the other warnings. But that isn't something available off-the-shelf in modern automotive management systems, and Subaru's price targets demand high usage of off-the-shelf technology.
The car is illuminating the check-engine light (and thus all the others) because there are a lot of sensors below your self-imposed waterline. Not all of them are waterproof, and in some cases they simply can't work underwater. Example- a catalytic converter simply cannot maintain normal operating temperature when submerged. There isn't enough waste heat to sustain the reaction when it is cooled by water from the outside. So even without water intrusion into the electrical system, the car is being pushed outside its normal operating parameters and it's completely fair to expect a diagnostic reaction. It's just annoying because the display behavior has been cranked up.
It's theoretically possible that they could put yet another sensor under there to determine if the car was in deep water, then use its data to suppress the other warnings. But that isn't something available off-the-shelf in modern automotive management systems, and Subaru's price targets demand high usage of off-the-shelf technology.
