Key won't go into the ignition

Pull the starter relay to isolate the ignition switch from the starter solenoid.

KEY WILL REMAIN IN IGNITION LOCK UNTIL CAR IS IN PARK FULLY. PERHAPS THE CABLE TO THE SHIFTER IS TO BLAME

Security. Turn the key to run. Let it sit for ten minutes, off for thirty seconds. Then try to start. Do this three times for a relearn. Don't try to start.

Might flash computer. Sounds like security is locking ignition out thinking something was stolen. This happens when car parts are changed sometimes.

bad battery or altenator

I have a 2004 impala that did the same thing..the ignition switch needs to be replaced

I have the same problem

May have to replace the key lock cylinder for the ignition. Do you have any other original spare keys that might work better?

Add Duplicate Key (PK3 or PK3+ key)
1. Insert an existing key into the ignition cylinder.
2. Turn the ignition cylinder to ON (RUN) and back to OFF.
3. Remove the existing key and, within fifteen seconds, insert the new key
and turn it to ON (RUN).
4. The security light will light up for two seconds to indicate success in programming
the key into the vehicle.
Originate New Master Key (PK3 or PK3+ key)

1. Insert new key into ignition cylinder and turn it to the ON (RUN) position.
The security light on the dash will illuminate and stay on for ten minutes.
2. When the security light goes out, you have one minute to start the next
step. Turn the ignition cylinder to OFF and then back to the ON (RUN)
position. The security light on the dash will illuminate and stay on for ten
more minutes.
3. When the security light goes out, you have one minute to start the next
step. Turn the ignition cylinder to OFF and then back on the ON (RUN)
position. The security light on the dash will illuminate and stay on for ten
more minutes.
4. After the security light has gone off the third time, the key has been programmed
into the vehicle’s computer and will operate the car. It has replaced ALL the
previous electronic key codes and is the ONLY key programmed into the
vehicle’s computer.

Add Duplicate Key (PK3 or PK3+ key)

1. Insert an existing key into the ignition cylinder.
2. Turn the ignition cylinder to ON (RUN) and back to OFF.
3. Remove the existing key and, within fifteen seconds, insert the new key
and turn it to ON (RUN).
4. The security light will light up for two seconds to indicate success in programming
the key into the vehicle.