B0091 00

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The front end sensor has been shorted to voltage, open, or shorted to ground.
The front end sensor current has been above 23 mA for longer than 5 milliseconds.
The SDM has not received a message from the front end sensor for more than 375 milliseconds.