HowToRepairGuide.com: Engine will not Crank after relearning Theft deterrent module?

First of all,i will say that this types of problems are very common on many other car models with TDM.
In this case this problem was noticed in 2003 Buick century car model.

After replacing the TDM,the relearn procedure was done,but still the security light does not turn off and the engine will not crank.

So in this type of problem you have to confirm that you have tried relearn procedure correctly.

If you dont know how to relearn,then check the link below :---------

Buick theft deterrent module Relearning?

http://howtobyme.blogspot.com/2012/01/buick-theft-deterrent-module-relearning.html

So first confirm yourself that you complete the steps exactly as stated ... After you turn the key to the crank position and released it to the run position and the security light was on... after returning to the vehicle 10 to 12 minutes later... are you waiting for the security light to turn off each of those time periods?

In some cases like this We may need a battery charger before too long. If system voltage goes low, that will affect it as well.

And due to low battery voltage also,TDM will not relearn.

But if you have tried all the steps correctly and Theft deterrent module is not getting relearn then .........

It appears as if there is a communication fault between the theft deterrant module and body control module. Often there is an intermittant concern and the relearn procedure above will at least get the vehicle started. Your condition is apparently not intermittant. The theft deterrant module is in the steering column and must transmit the proper signals to the body control module at the proper time. The BCM must interpret the signals and then in turn send the proper message to the PCM (powertrain control module) to enable fuel and cranking. You will likely need a dealer scan tool or equivalent to determine if the fault is in the theft module, bcm or pcm. Most often it is the theft deterrant module but on occasion it can certainly be a wiring issue or BCM failure.

The theft module is in the column, the bcm in the dash and the pcm under the hood.
As per 2003 Buick century car model details ..............

Your system should be passkey system.
If you have access to a digital volt ohm meter what you can do is check the resistance across the pellet in the ignition key.
Then go under the dash and locate the c207 connector. This should be two white wires and is usually in an orange insulation.
Insert the ignition key into the cylinder and read the resistance between the two wires at the c207 connector going into the steering column. What we're testing here is the wiring though the steering column and the cylinder. The resistance should be close to what the resistance of the pellet in the key alone was.
If it is not or it is open then we need to replace the ignition cylinder.
You will need your old key to have the pellet read by a special tool at your dealers parts department(there are 15 different pellets) and a new key cut for the replacement cylinder.

Test it several times and while turning the ignition key back and forth with the meter leads attached to the column harness. Often the wires can make intermittent contact while the ignition is being turned. Just a double check before you passing this component and moving on.

This details will help you thanks.

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