I have been reading about people buying a spare ECM and TCM. Why is this?

What does it mean when a ECM or TCM is locked?

Can I get a "used" TCM and ECM from a junk yard and be able to use it? What does a new unit cost?

Thanks :)

I have been reading about people buying a spare ECM and TCM. Why is this?

What does it mean when a ECM or TCM is locked?

Can I get a "used" TCM and ECM from a junk yard and be able to use it? What does a new unit cost?

Thanks :)

Some people like to keep their stock ECM/TCM somewhat virgin for those occasional trips to the dealer.

Locking is a feature in EFILive and some other types of tuning software where the tuner can prohibit reading or writing to the ECM using a lock down option.

Yes, you can get a core ECM from a junk yard and use EFILive to reflash it for your truck.