ECM VATS Relearn:

[diesel vein]

Trying to load a tune to adjust for bigger injectors .kept getting no data received .after ten or so tries the truck will not turn over.security light comes on when i lock the doors with the lock button and close them.remote does not work..now it says em is in an unknown state when i try to read the tune in the truck.

 

[slowlb7]

Sorry to bring this back from the dead but had a question do you turn the key off each time then try to start or just to run then start then back to run?

When you switch ECM's, your truck probably will crank, but won't start.

Here's how you "teach" the truck your new ECM:

Turn ignition on
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.

In 10 minutes, the light will go out, and it will start up, and will "marry" the ECM to the BCM permanently.

This will even work with locked "pre-programmed" ECM's so you can test them on other trucks.

I'm pretty sure I've posted this before, but just in case, I posted it again.

 

[duramaxzak]

I have had to do this before and it worked. Leave the ignition on, and make sure you have a battery charger on it so the batteries don't drain down.

 

[shogundogun]

VATS relearn....

You guys just made my day! This is slow and tedious, but it worked!!

 

[x MadMAX DIESEL]

You guys just made my day! This is slow and tedious, but it worked!!

You can change the sercurity time to 10 seconds and make it work in 30 seconds if you wanted

 

[Slick03Max]

Thanks everyone for the info added to this post!!!
Just got my lbz transplant to start today!!!
Had to shut my key off for the 5 seconds between each 10 minute interval!!!! Runs like a charm!!!

 

[firestone]

I tried this but I first read to leave the ignition on and not turn to off. I tried cranking a few times and then started the procedure. I read to do it twice. It didn’t work. Then I noticed the security light wasn’t staying on and I read more and tried the ignition off before restarting. I didn’t wait 5 seconds though, and the security light didn’t come on. Now, it seems the security light won’t stay on ever no matter what, just comes on for a couple seconds then goes off. I am not sure what I have done but I hope I haven’t permanently messed anything up!

LLY/ECM transplanted into an LB7 truck/BCM.

 

[2004LB7]

If the security light comes on when you first turn the key but goes off a few seconds later then I would think that the VATs have been satisfied and it should start. If it doesn't you may have something else wrong that is preventing it from starting. Does it turn over at all?

 

[firestone]

Yes it cranks over for a few seconds and then it stops itself from cranking. All the dash lights cycle and then it will crank again if you try it again. But it always stops the cranking itself afte a few seconds.

 

[Burn Down]

I tried this but I first read to leave the ignition on and not turn to off. I tried cranking a few times and then started the procedure. I read to do it twice. It didn’t work. Then I noticed the security light wasn’t staying on and I read more and tried the ignition off before restarting. I didn’t wait 5 seconds though, and the security light didn’t come on. Now, it seems the security light won’t stay on ever no matter what, just comes on for a couple seconds then goes off. I am not sure what I have done but I hope I haven’t permanently messed anything up!

LLY/ECM transplanted into an LB7 truck/BCM.

Vats is working properly, as mentioned above sounds like something else is going on.

 

[firestone]

I cleared the incorrect security signal error code from the ECM and a crank position code with a cheap scan tool, then it started. I also changed the sensor but I still got the same code later.

 

[05LLYDMAX]

I had no luck with Pats original procedure on an 04 LB7, but I did get this method to work first try.
Turn ignition on, wait 5 seconds before cranking.
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Turn ignition off for 15 seconds
Repeat this process 3 times after the 3rd 10 minute wait the relearn was complete

 

[dndj]

I had no luck with Pats original procedure on an 04 LB7, but I did get this method to work first try.
Turn ignition on, wait 5 seconds before cranking.
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Turn ignition off for 15 seconds
Repeat this process 3 times after the 3rd 10 minute wait the relearn was complete

This is consistent with the factory service manual for the LB7. Need to turn the key off for 5 sec after the security light goes out, then attempt to start again. Starts after the 3rd time.

 

[2004LB7]

I've always had best luck when I turned the ignition off for about 15 seconds instead of 5 to let the ecm fully shut down between each cycle

 

[dndj]

I've always had best luck when I turned the ignition off for about 15 seconds instead of 5 to let the ecm fully shut down between each cycle

No doubt leaving it off a little longer won't hurt at all. Thanks for the tip. :thumb: