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Discussion Starter #1
I have this 2003 cts. The ecm went out of it (so I thought) so I replaced that. It was doing all the normal stuff when the ecm goes out, except it would run and drive. I got the new ecm from Deerings auto, programmed ready to use. I put the new one on and it fixed everything except now it won’t start. The key still won’t come out of the ignition and the shifter won’t shift.
Any ideas would be helpful.
Thanks.
 

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I have this 2003 cts. The ecm went out of it (so I thought) so I replaced that. It was doing all the normal stuff when the ecm goes out, except it would run and drive. I got the new ecm from Deerings auto, programmed ready to use. I put the new one on and it fixed everything except now it won’t start. The key still won’t come out of the ignition and the shifter won’t shift.
Any ideas would be helpful.
Thanks.
This is what I FEAR is the issue with GM's (Known Issue) Anti-Theft problems.
When the system is triggered, for whatever reason, it takes a bunch of electronics with it and then you are stuck needing to replace MANY different items in order to resolve all of the symptoms.
SO now I am searching and compiling information related to each item. (Just got started searching, don't have much yet)

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KEY REMAINS STUCK AFTER GETTING IT RUNNING:
Well I had the pass key module replaced fixed issue with not turning to off position and starts
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Exactly which symptoms did change when you replaced the ECM ??
 

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Discussion Starter #3
This is what I FEAR is the issue with GM's (Known Issue) Anti-Theft problems.
When the system is triggered, for whatever reason, it takes a bunch of electronics with it and then you are stuck needing to replace MANY different items in order to resolve all of the symptoms.
SO now I am searching and compiling information related to each item. (Just got started searching, don't have much yet)

---------------------------------
KEY REMAINS STUCK AFTER GETTING IT RUNNING:
Well I had the pass key module replaced fixed issue with not turning to off position and starts
---------------------------------

Exactly which symptoms did change when you replaced the ECM ??
The dic information started showing up again. The fuel gauge started working. the speedometer quit working. And the car would not start.
 

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I have this 2003 cts. The ecm went out of it (so I thought) so I replaced that. It was doing all the normal stuff when the ecm goes out, except it would run and drive. I got the new ecm from Deerings auto, programmed ready to use. I put the new one on and it fixed everything except now it won’t start. The key still won’t come out of the ignition and the shifter won’t shift.
Any ideas would be helpful.
Thanks.
This is what I was wondering about, more specifically. "It was doing all the normal stuff when the ecm goes out". Exactly what were the symptoms? When you say doing all the normal stuff, ... or it fixed everything, ..... it is a bit of a mystery what all these things might have been. Did you have any Anti-Theft issues ??
 

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Discussion Starter #5
Yes, there is anti theft issues. That is the main problem. The dic is not working and neither is the fuel gauge.
thanks for the feedback.
 

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'93 SedanDeville 60 Special
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The PCM and BCM share a security code
When you swap either then the new controller is not sync'd to the other and thus BCM is in security mode preventing at start
There is a PCM/BCM relearn process you need to see what it is for your car.

Many times when door is open if there is a security light on dash, if it does not blink then the 2 controllers are not sync'd for the security code
To prevent crooks from stealing a vehicle the relearn process is timely like key on (engine off) for 10 mins then key off for 5 seconds.
This is done 3 cycles so over 30 mins so assure battery is fully charged
If done right then on 3rd cycle the security light will start flashing and a DTC security code is tripped and needs to be erased
Check what your car's relearn process is

To prevent that from happening in future this process can be turned off in a tune
 

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'93 SedanDeville 60 Special
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This is how I do it for like Corvettes

30 Minute Learn Procedure

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.

5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the password on the next ignition switch transition from OFF to CRANK).

Important:

The vehicle learns the password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

Start the engine (the vehicle has now learned the password).
With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).
 
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