Originally Posted by TWong1200

I think it's ridiculous for the dealer to say that the engine is bad because the knock sensors detected piston slap. Untrue. Knock sensors do not detect piston slap. They are Knock sensors, period. Now the dealer could say that they themselves hear piston slap but saying it's because the knock sensors are sensing it is completely false.

If you're getting an engine light and it points to the knock sensors, I'd say figure out if the car is truly knocking or not. Has it had a tune-up lately? Do you run the proper grade fuel? If you've done that and are running good fuel, then you could just have a bad knock sensor(s). Start with the small things first.

To clarify, do you hear it most when started up first thing after it sitting and getting cold? And does it lessen as it heats up? These are typical signs of piston slap.