2003 Chevrolet Impala Ignition Lock Cylinder Replacement

This post is for replacing an ignition key tumbler kit in a 2003 Chevrolet Impala but it applies to most General Motor Vehicles from the late 1990’s to 2007

With a small screwdriver depress the retaining pin, rotate and pull the tumbler assembly from the sensor housing.

The retaining pin can be seen in the picture below. It is the angle piece pointing down. Before further disassembly place your thumb on the locking bar and take the key in and out of the tumbler assembly so that you can get a feel for how the locking bar should drop into position when the key is inserted. This is helpful to know later when assembling the new tumbler

The retaining bar will have to be removed.

Use a small screwdriver to pry it out of the housing.

After the bar is removed, take all of the springs out.

Next take a pick and lift out one tumbler at a time.

Make yourself a chart so that you can write down the numbers that are on the individual tumblers and keep track of their positions in the tumbler housing. This is your key code. You can get this code from your dealer if you need to but you will have to show a photo id and proof of vehicle ownership.

The original tumblers are brass colored and the replacements are silver colored. There are numbers stamped on each one and they range from 1-4

In particular, if you have never done this before and do not have any spare parts, make sure that the package is unopened. This will save you a lot of grief.

Install the new tumblers in the proper order and check with the key to make sure that the locking bar drops in evenly when the key is fully inserted and the tumblers are pushed in to make contact with the key.

If the bar does not drop in evenly you have either assembled incorrectly or your key is worn out.

Remove the key and push all of the tumblers fully in, light pressure with a small screwdriver or pick is all that is needed. With the tumblers pushed in, place the new springs into position

Ignition Switch 21

Install the new retaining bar.

Install the new spring and angled retainer. Not shown but it should go in the square hole that is pointing down at the right hand side of the tumbler housing.

Insert supplied grease into the tumbler assembly and install in the new sensor housing.

There are detailed instructions that come with the kit you should read and fully understand before actually attempting this repair. The information I am providing is meant to be an aide to the factory instructions.

10 discussions on “2003 Chevrolet Impala Ignition Lock Cylinder Replacement”

  1. Just bought the car two months ago did 3 oil changes oil was dirty lucas and good oil starting to think i got it too clean just put a trans in it its weird tho as soon as that security light hit it knocked im really good with the back yard mechanic stuff this security light poped up and wham knock

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