DTC P1270: Accelerator Pedal Position Sensor A/D Converter Error: Description
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) reads analog data from the accelerator pedal position (APP) sensor and processes the analog data into digital data in order to interface with the powertrain software. If the ECM microprocessor can not perform this task, this DTC will set.