DTC P2128: Accelerator Position Sensor 2 Signal Circuit High Input: General Description

The Accelerator Pedal Sensor (APS) is part of the Electronic Throttle Control (ETC) system. Along with the Throttle Position Sensor (TPS) signals is sent to the ECM/PCM, it controls the needed fuel delivery based on the driver's demand. The APS is divided into APS 1&2 and has independent power and ground circuits. APS 2 shows 1/2 the output voltage of APS1. The ECM/PCM compares delta (difference) of APS 1&2 signals. When a fault exists in either APS 1 or APS 2, the opposite (good) circuit will override and go into limp-home mode.