PCM and BCM removed and reinstalled

[Alberta Tahoe]

Quick question as I work through a litany of issues with this 06 Tahoe.
During the course of trouble shooting I have removed and reinstalled (without replacing) the original PCM and BCM.
What are the requirements after this has been done? I understand that a key re-learn is needed if the PCM has been removed. Is that right? Anything else?
Thanks in advance as always.

 

[Scottydoggs]

with the battery not hooked up. plug them both back in, hook up battery, and start it up. all should be fine.

only need the security learn if you changed the pcm.

 

[Alberta Tahoe]

Thanks for that. It may be too late as I've had them in and out some time ago and have re and re'd the battery numerous times as well. However, they are still both the original components so perhaps I haven't compounded the problems by having taken them out in the first place.

 

[Scottydoggs]

none of that should matter really. what exactly is it doing when you try to fire it up?

 

[Alberta Tahoe]

... what exactly is it doing when you try to fire it up?

Nothing.
I've a few threads here about the entire saga.
Started with an intermittent electrical issue.
Progressed to a no start/no crank condition.
Changed ignition switch.
No improvement.
Dash instruments time out after 30 seconds.
Present state: No crank. Key on will activate gauges, turn on various indicating lights. This will time out after 30 seconds or so. Ignition key useless at that point. Dash frozen.
Have to re and re the battery to reset. Now stands as still un-repaired.
If you're interested here's a link to all the related threads. The first listed is the most recent.

https://www.tahoeyukonforum.com/threads/tech-2-no-communication-message.106643/

https://www.tahoeyukonforum.com/thr...ndition-with-radio-also-in-locked-mode.95643/

https://www.tahoeyukonforum.com/threads/electrical-issue-is-expanding.93566/

There's more too...

 

[Scottydoggs]

the security light stay on?

try jumping the starter motor yet?

test for power on the small wire on the starter when the key is turned to crank? thats the signal wire when the key is turned to crank.

 

[Scottydoggs]

quickly looking over your other threads you might have a host of bad grounds.

 

[Alberta Tahoe]

the security light stay on?

try jumping the starter motor yet?

test for power on the small wire on the starter when the key is turned to crank? thats the signal wire when the key is turned to crank.

The security light does not stay on.
I can crank the starter by applying 12v to the start relay winding.
I don't believe I'm getting a signal to the PCM to hit the start relay. Among other things.

quickly looking over your other threads you might have a host of bad grounds.

That's a given I think. And possibly corrupted +v to the PCM.

 

[Scottydoggs]

if you turn the key to run, then jump the starter, will it run?

 

[Alberta Tahoe]

Nope. Just cranks over. In addition to not getting a signal to the start relay (via the key), I'm also not getting anything to hit the injectors. I can't say that I've even heard the fuel pump prime. Pretty sure all that is related to having replaced the ignition switch, electrical portion.