When the P2127 OBDII diagnostic code is set, it indicates that the Powertrain Control Module (PCM) has detected that the Throttle Position Sensor (TPS) has an excessively low voltage. Depending on the vehicle model, the limit of this voltage can be between 0.17 to 0.20 volts.
It should be noted that the “E” description of this code may refer to a particular circuit or sensor. If the PCM sets this code, it is because the signal is below 0.17 V and caused by a short to ground or lack of reference voltage.