[bluGill]

> Wouldn’t the Magnuson-Moss Warranty Act still apply?

The act is intended to allow voiding the warranty after modding the ECU (even though the act predates ECUs and so doesn't mention them). Well your radio warranty would probably still apply, but modding the ECU has potential to damage the engine, and therefore the engine is out of warranty if you touch the ECU code.

[josephcsible]

I thought for something to void the warranty, it actually had to cause the damage, not just have potentially been capable of doing so.

[bluGill]

It is very difficult to mod an engine in a way that will not cause damage. Sometimes the damage won't show up for many years.

[josephcsible]

You're talking about the possibility of maybe eventually causing some kind of damage, but isn't the important question whether it caused the specific damage that the owner wants to be repaired under warranty?