Where is the evap emission sensor. I have Code 452

the following links can assist you
P0452 EVAP Pressure Sensor Switch Low
P0452 EVAP Pressure Sensor Switch Low P0452 OBD II Trouble Code P0452 Evaporative Emission Control System Pressure Sensor Low Input How to troubleshoot an EVAP Pressure Sensor problem P0452 GM

Maybe.
Codes 121 and 122 are for the throttle position sensor circuit.
Code 400 is EGR and codes 449 and 452 are for the EVAP system.
Code 1639 is for a problem with the 5 volt reference circuit from the engine computer.
The throttle position sensor could be failing which could prevent the gas pedal from working. And the 5 volt reference problem could shut down the computer which would kill the engine. EGR is an emissions component and EVAP is the system that vents gas fumes from the gas tank.
Codes are only a guide for a mechanic to troubleshoot the circuits involved. They do not mean a component is faulty.

been getting a code of p0452 EVAP CONTROL SYSTEM PRESSURE SENSOR low so i took the charcoal canister apart and found the green wire going to the pressure sensor is broken going into the grey wiring clip that goes onto the pressure sensor

P0446 has nothing to do with the canistor !
DTC P0446 Evaporative Emission (EVAP) Vent System Performance
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.
DTC P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage


How to troubleshoot an EVAP Pressure Sensor problem P0452 GM

EVAP Vent Solenoid Code P0446 The solenoid is stuck open !

(PO452 general motors code, low evaporative emmisions control input) Believe it or not it could be that the gas cap is not on tight or needs to be replaced. Other than that: vacuum line or evap. canister leak.

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P0450 Evap Emission Ctrl Sys Pres Sensor Error
P0451- Evap Emission Ctrl Sys Pres Sensor Range/Perf
P0452- Evap Emission Ctrl Sys Pres Sensor Lo Input
P0453- Evap Emission Ctrl Sys Pres Sensor Hi Input
P0454 Evap Emission Ctrl Sys Pres Sensor Interm
P0455- Evap Emission Ctrl Sys Gross Leak Detected
P0456- Evap Emission Ctrl Sys Very Small LeakDetected)
P0457 Evap Emission Ctrl Sys Leak (fuel cap loose/off)
P0458 Evaporative Emission Sys Purge Ctrl Valve Circ Low
P0459 Evaporative Emission Sys Purge Ctrl Valve CircHigh
P0460- Fuel Tank Level Indicator Circ Error
P0461- Fuel Level Sensor Circ Range/Per

P2408 Fuel Cap Sensor/Switch Circ
P2409 Fuel Cap Sensor/Switch Circ Range/Perf
P2410 Fuel Cap Sensor/Switch Circ Low
P2411 Fuel Cap Sensor/Switch Circ High
P2412 Fuel Cap Sensor/Switch Circ Interm/Erratic

P0453 KIA - EVAP Emission System Pressure Sensor High Input

There is no one magic bullet fix.
Here are the poss issues that trigger the code and light.Evaporative Emission System (EVAP) Pressure sensor harness is open or shorted
- Evaporative Emission System (EVAP) Pressure sensor circuit poor electrical connection
- Faulty Evaporative Emission System (EVAP) Pressure sensor
- Damaged fuel tank pressure sensor (same part as above)

Evaporative emission control system pressure sensor, is showing high (453) & low ( 452) input. Check all hoses to vapor canister, as well as connections. Link below will give you an idea where/what to look for.

http://alflash.com.ua/evap.htm

code 452 is EVAP emission control system pressure sensor low
motor is surging?
EGR may be blocked
Cheers Rob

This indicates that a part of the Evap control system  is no longer functioning correctly. The Evap system consists of many parts, including (but not limited to) the Gas Cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a cars fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.
A code P0440 could mean one or more of the following has happened:
The gas cap is not installed or working properly
The purge solenoid has failed
The canister is plugged and not working properly
TRY this first: Remove and reinstall the gas cap or replace, clear the code, and drive for a day and see if the codes come back.
Inspect the Evap system for cuts/holes in tubes/hoses
Inspect for damaged or disconnected hoses around the Evap purge solenoid
Check and/or replace the sensor
Check and/or replace the purge valve

P0452 Evaporative Emission Control System Pressure Sensor Low Input

Good luck and hope this helps. Recap star with the simple and replace the gas cap with a dealer OEM not a after market. If that does not fix it then change the sensor as indicated with the P0452 code. You can get the sensor from Auto Zone and they can give yo the step by step instruction to get the job done. Good luck and keep me posted.