Possible Causes

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

AAT sensor voltage above 4.8 volts.
AAT sensor.
(G31) AAT sensor signal circuit shorted to battery voltage.
(G31) AAT sensor signal circuit open.
(K4) Sensor ground circuit open.
PCM.