Check the fan relay for the 1996 Cavalier. Also, check the coolant sensor, one of these is most likely bad.
ets and check engine light on in 98 Chevy cavalier
The coolant level sensor is faulty.
If it is the low coolant light, it may mean your coolant is low. If it is not low, it may be the low coolant light sensor malfunctioning.
The knock sensor is located on the side of the engine block near the bellhousing
PO1406 ERG valve pintle position circuit error.
light should go off . if that was the problem, and is now fixed, disconnect the battery for 5 minutes,then reconnect battery this will reset the computer and remove the signal from the warning light if that doesnt work, there is a different problem apart from crankshaft sensor
The check engine light will illuminate.
change coil module
There are many sensors that can trip the check engine light to come on.
Could be the knock sensor.
check this site out