There are 2 ways it can work. One is if you gradually bring it to the redline, it will cut the engine intermittently to bring the engine speed back down. However, there's nothing it can do to prevent the engine from over-revving if you shift into first when you meant third, or if you miss a shift or otherwise floor it out of gear. The revs climb too fast for it to be effective.
If you hit it gradually, you're fine. If not, you might have scrooged something...
Brent
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