Check eng light is on

These codes appear to relate to your throttle poistion sensor(s) - check your throttle cable linkages and in particular the position sensor on the throttle body.

What brand part did you use ? Dorman ? OE ? Did you test the circuitry ? Did you just read the code an replace the part ? 2009 Chevy Silverado P2138 Accelerator Pedal Position Chevy is same as pontiac ! Drive by Wire training

P0411 is an air injection pump code
P1125 and P2138 are both accelerator pedal position sensor codes

P1125 and P2138. One is for the TPS and the other is for the gas pedal. the pedal sensor is going bad, because it sends a false signal to the throttle position sensor. all of these codes are pedal position related. Hope this helps you out!

Check coolant level and strength ,thermostat,coolant sensor and temperature sensor,171 dirty fuel filter,dirty MAF sensor,bank 1 sensor 1 O2,PVC valve,vaccum leak,exhaust ,you can try smok test.

Generic OBD Error Code Details for P2183 Engine Coolant Temperature Sensor 2 Circuit Range/Performance
You could have a stuck open engine thermostat.

Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion.

P0700

The transmission of a vehicle which has suffered a transmission problem will send the P0700 code to the vehicle engine control module (ECM)

P0705 Transmission Range Sensor Circuit Malfunction

Possible causes

- Open or short park/neutral position switch circuit
- Poor park/neutral position switch circuit connection
- Misadjusted park/neutral position switch
- Park/neutral position switch may be faulty

P0455. A code p0455 most likely means one or more of the following has happened:

A loose or improperly affixed gas cap

A non-conforming gas cap (i.e. not factory/original brand)

Other leak or damaged piece in EVAP system

P1125 Accelerator Pedal Position (APP) System

P2125 Throttle/Pedal Position Sensor/Switch "E" Circuit

P2138 Throttle possition sensor

There is a GM service bulletin on this particular item. basically covers both codes your getting.
#07-06-04-019A: Intermittent MIL/SES, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector)

Models: 2005-2008 GM Passenger Cars and Light Duty Trucks (Including Saturn)