DTC P1270: Accelerator Pedal Position Sensor A/D Converter Error: Description
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 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 then this DTC will set.