I guess the knock sensor could cause this,anything is possible, but I have never seen a knock sensor do anything like this. The first step is it get your vehicle hooked up to a Subaru scan tool, and get the engine light fixed.
There are numerous warning lights for a Mazda RX8. Some of the warning lights are for engine oil, charging system, ABS, and check engine.
check warning lights
There are several warning lights on a 1997 Grand Am. Some of the warning lights are the ABS system, oil lights, and the check engine light.
By "OFF," I have to assume that your question means that the ignition switch is "ON", but the engine is not running. IF that is what your question means, then the reason the engine warning lights turning on is that the manufacturer designed the system that way to show you that those warning circuits and lights are working, and ready to warn you after you start the engine, should there be a failure in one of the systems they represent.
2003 Nissan Murano "engine service", "VDC Off" and "slip" warning lights on. What does it mean?
The warning lights on a 1988 Toyota Celica will usually mean that your engine is needing to be serviced. However, the warning lights can also mean that your brakes need to be serviced or repaired.
small engine symbol
small engine symbol
There are several reasons why a Toyota's warning lights may come on. The lights may come because there is a problem with the engine, low oil, or even bad brakes.
Warning lights on a 2008 Honda Accord include the gas light and the check engine light. There is also lights that come on when doors are open.
Most of the light on the dashboard are Warning Lights; different warning lights that might flash up on the dashboard. Some of the more common warning lights are shown below. 1 = Oil pressure warning light 2 = Battery charge warning light 3 = Brake system warning light 4 = Engine warning light
The Vectra warning light is called the engine management warning light. It tells you that you need to get your Vectra checked by a mechanic.