I have multiple codes Chevy 1500, p2120, p2125, and p1125

Question

I have a 2004 Siverado 1500 4x4 with a 5.3 liter engine,
also have reduced engine power mode

Answer 1

P1125 APP 1 (Accelerator Pedal Position) Sensor and APP 2 Sensor is more than the predicted value.

P2125 APP 2 sensor circuit

P2120 APP 1 Sensor circuit

In order for these code condition to occur the APP sensor are outside the predicted value. Without the throttle being depressed APP 1   and APP 2 should be at 0.24 volts - 2.24 volts. When these 2 code appear the ECM see a voltage less than 0.24 volts are more than 4.49 volts. To see more than 4.49 volts this would be a disconnection at the harness if the ECM see less than 0.24 volts look into the harness for moisture that can have enter in there creating corrosion. This should be done with a scan too that read the APP position . 1 and 2, The refferrence voltage for the APP sensor also needs to be measured with a volt meter either at the APP sensor or the ECM