2009 Chevy Impala key stuck in ignition

This is how you do a security system reset on an Impala. I hope you have the transponder receiver connected on the new column.

https://www.vehiclehistory.com/questions/how-do-i-perform-a-chevy-impala-security-reset-93585

Chevy Impala Won't Start Security Light - It Still Runs

https://itstillruns.com > chevy-wont-start-security-light-...
Make sure the security light is flashing. After 10 minutes the security light will stop flashing and either turn off or stay on steadily. When it does, then ...

How to reset anti theft system on a 2008 chevy impala - Fixya

https://www.fixya.com > ... > 2008 Chevrolet Impala
Sep. 1, 2019 - Turn ON the ignition, with the engine OFF. · Attempt to start the engine, then release the key to ON (vehicle will not start). · Observe the SECURITY light, after ..

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Does the car have floor shift or column ?
Ignition Key Cannot Be Removed from the Ignition Lock Cylinder (Column Shift)
Ignition Key Cannot Be Removed from the Ignition Lock Cylinder (Floor Shift)

Ignition Key Cannot Be Removed from the Ignition Lock Cylinder (Column Shift)
Step
Action
Yes
No
1
Did you review the Steering Wheel and Column Description and Operation and perform the necessary inspection?
YES - Go to Step 2
NO - Go to Steering Wheel and Column Description and Operation
2
Verify the key cannot be removed from the ignition lock cylinder.
Is the key stuck in the lock cylinder?
Go to Step 3
System OK
3
Is the vehicle equipped with a manual transmission?
Go to Step 7
Go to Step 4
4
Turn the ignition key to the OFF position.
Can the key be turned to the OFF position and be removed?
Go to Step 7
Go to Step 5
5
Verify the adjustment of the automatic transmission cable. Refer to Range Selector Lever Cable Adjustment .
Can the key be turned to the OFF position?
System OK
Go to Step 6
6
Inspect the linear shift assembly and cable for damage.
Is the linear shift assembly or cable damaged?
Go to Step 9
Go to Step 7
7
Inspect for a faulty lock cylinder.
Is the lock cylinder damaged?
Go to Step 10
Go to Step 8
8
Inspect the ignition lock cylinder case.
Is the worn, damaged, or loose?
Go to Step 11
Go to Step 12
9
Replace the linear shift assembly. Refer to Linear Shift Assembly Replacement .
Did you complete the repair?
Go to Step 12
--
10
Replace the ignition lock cylinder. Refer to Ignition Lock Cylinder Replacement .
Did you complete the repair?
Go to Step 12
--
11
Replace the ignition lock cylinder case housing. Refer to Ignition Lock Cylinder Case Replacement .
Did you complete the repair?
Go to Step 12
--
12
Operate the system to verify the repair.
Did you correct the condition?
System OK
Go to Step 2

wheels could be turned, also make sure your not missing a release button on your steering column.

Hi there all the things you explain are and need power to operate, make sure your battery has 12.6 volts or more and try again , if your battery doesn't have that voltage then you will need a new battery, hope this helps

Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator: If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The column ignition lock system consists of an ignition lock cylinder control actuator, and a park position switch that is located in the automatic transmission shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.

Does your impala have floor shifter ?

Locksmith.

Somtimes you need to turn the steering wheel a little to allow the lock to engage.

Try depress the unlock button while moving the steering back and forth a little. Try a lot..
If not work, drape a scarf or towel over steering column to hide key in ignition, and use spare key to open door lock. You do have spare key?
Check your insurance, you may have lock smith lock out coverage.
Good luck.

If you mean remove the ignition tumbler from the steering column, you will have to remove the steering wheel and lock plate, then you will need to remove the turn signal lever and screws, and then pull the turn signal switch up and out of the way, you should then be able to see the housing for the ignition tumbler down in the steering column. Look at the tumbler housing and there should be a small slot towards the end of the housing that you can put a small standard screwdriver into and depress a locking latch that is built into the tumbler. When this latch is depressed you will be able to pull the ignition tumbler straight out of the column.

push the key in all the way with the ignition ( key holder) toom with one hand, with the other hand turn the lock steering wheel side to side while depressing the brake pedal - good luck

Not sure what you mean by a head unit, but best thing to do is to start taking it apart again 'till the key is again free...then look to see what was binding.