Since Allan quoted and answered #1, I'll take care of #2.
2) get yourself a DVM and some wire to pull the codes. (You don't need a
ripoff "code reader")
Exactly. Analog would work better than a digital volt meter. Also, I
created a setup that will output codes (yes, in the form of flashes - it's
not *that* hard to count them). It's setup specifically for the XR4Ti, but
should be applicable to any EEC-IV.
It's under "3 Dollar Code Scanner" on the Tech Articles page. Even if you
want to use a volt meter to read the codes, this page includes the diagram of
where to plug what and what to jumper.