Fuel Cutoff Mode

WARNING: This page is about a different car, the 2005 Buick LeSabre. However, it is still accessible from the selected car via links, so may be relevant.

The PCM cuts-off fuel from the fuel injectors when the following conditions are met in order to protect the powertrain from damage and improve driveability:

The ignition is OFF. This prevents engine run-on.
The ignition is ON but there is no ignition reference signal. This prevents flooding or backfiring.
The engine speed is too high, above red line.
The vehicle speed is too high, above rated tire speed.
During an extended, high speed, closed throttle coast down. This reduces emissions and increases engine braking.
During extended deceleration, in order to protect the catalytic converters.