In my recent talks with certain friends in Honda, I have learned some interesting info. If you were to ask your Service Department at your local dealership, they will confirm everything I say.
More advanced Honda ECU's, particularly the 06+ models have very advanced ECU's. The record everything that you do. There are flags for recording that Honda can review with their readers at every service department. These flags include how many times you've hit your rev-limiter, what position your throttle is at, what temperature your engine is before and after the radiator, and what your fuel/air ratio is. When your ECU records a certain "flag" issue, it will record live what your car was doing before, during, and after the time of the flag. Honda will then use these flags timelines to determine if any issue that you are claiming may be a result of abuse on the vehicle or "driving it outside of it's designs."
Some examples of warranty voiding issues:
Lets say you want to go drive your car hard. Maybe you own an LX/EX. These cars are designed for "fun economy." Their rev-limiters are simply for idiot proofing and not designed for you to shift at. Lets say after a night of beating on your car, racing, or whatever you do, you have an issue. Maybe your engine is ticking, or something funky is going on in the transmission. Maybe you simply get an engine light and your car isn't "running right." So you take it in. Now Honda opens up your ECU and finds that you have hit your rev limiter 20 times in 2 days. They then can open it further to find that you have been driving above the car's "intended design." They find you've been accelerating quickly, your engine temp before your radiator is above normal, and you've been basically beating the shit out of your car. Then the Honda rep is called in. He takes the data and determines whether or not they are going to honor your warranty. For the economy type vehicles, the EX/LX type Civics are not designed to be raced or driven hard. Driving in such manner can cause your warranty to be voided permenantly.
Another example would be if you wanted to run nitrous. Say you mis-jet your nitrous, or your engine simply gives out from the added power. Now you take your car into the dealership. They open your ECU to show that your car is accelerating hard, and the air/fuel ration is different than what the engine is designed for. They can break it down to the point that your 02 sensor sees a rich condition, where the wet kit will normally bombard your engine, or the dry kit will cause an instant lean. They can then determine by your engine temperature, your aggressive acceleration, and your tainted a/f ratio, that you have done something to modify the engine and therefore void your warranty permenantly.
I was told that Si's have a little more leeway, as they are vehicles marketed for "high performance." Therefore, hitting the rev-limiter is not harmful, and therefore usually overlooked. However, consitently "racing" your vehicle will void the warranty, so careful who you cut off on the highway, it might just be the guy who sold you your car.
To be candid, if you make an effort to revert your car back to stock before taking it in for service, Honda will usually just honor those things they aren't supposed to in an effort to keep your business and your loyalty. Make a number of trips to the service department, and they consistently pull the same abuse reading from your ECU, they might tell you to take a hike.
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