Originally posted by idealrides
And if all hell broke loose and my ECU were to see a neutral when I wasn't actually in neutral, what would go wrong? Nothing!
I'll be the first to admit I know next to nothing about engines and the ECU's that controls them, but I do know that after I start my car in neutral, once I put it into gear, the RPM's drop. I suppose this is a response to the neutral indicator wire. If that circuit were fried, the ECU may not be able to manage RPM appropriately, and I doubt that would be a good thing.
Besides, it takes all of two minutes and 20 cents to wire a diode! I actually wired two, and fused it, for a little extra insurance. And netZ's suggestion to test it occasionally is a good one; I do it regularly.
On the other hand, if the diode opened completely, the neutral protection wouldn't be there anymore. That's fairly unlikely, though, and I'd rather protect the expensive ECU circuitry.