Spare ECM issues on 08 LMM - security issue

[u00bse1]

Need some help, missing something here.

Got a used 08 LMM diesel ECM to have as a spare. Truck is also an 08 LMM. With factory ECM, truck is perfect. When the spare ECM is in it, I get the dead key and security message on the dic. I did license the spare ECM, programmed it fine with a know good tune, changed the spare ECM VIN to match the truck. Tried the 30 min key learn (3 separate 10 min cylces) several times and nothing. Still dead key and security light.

What am I missing? Something different in the 08 vs the 06/05 down I am not aware of?

Factory ECM I can program and truck runs perfect. Spare ECM I can also program, but dead key and security issue.

[tc1]

Did you write entire?

[tc1]

Did you write entire?

After vats delete.

[mecanicman]

HPT does not do a write entire to the LMM pcm(not sure about any dmax pcm)

[u00bse1]

I will say Yes, I did push the full write button, I have read it really only does a partial as Mecanicman says. So what really happens regardless of what button you push is maybe the issue????

I will say I wondered about writing the security parameters. I did try and turn off VATS on the used ECM, as well as change the Key cycle count and seconds of wait on the VATS and it did not appear to take effect. I cant see that it changed those area.

So, what other questions.

Thanks guys. I appreciate it.