Well I don't think anyone has a true wright up with step by step yet.
But it takes a volt meter and a jumper wire / paper clip.
I know it's described in the manual on how to pull the codes and also a list of codes.
The manual is in the manual section > over 216 manuals > montero it covers your truck It's like the 4th one down.

codes http://www.mightyram50.net/vbulletin...uble+Code+List