Question on '92 Dynasty

I have a 1992 Dodge Dynasty, 3.3, A604, 134000 miles. Yesterday I did the
on-off-on-off-on to check to see if their were any codes stored. I do this
about once a month. Last month there were no codes, but now I get a code 12
and code 35.
A code 12, I believe, means that the battery has been disconnected. I
don't understand why I have a code 12, since the battery connections has not
been touched for almost a year. So why a 12 all of a sudden?
A code 35 relates to the fan relay. If the fan relay shorted for an
instant before it opened, could this have caused the computer to think that
a power loss from the battery had occurred (hence the 12)?
Any help would be appreciated!
Thanks.

Bret

 

Code 35 basically means either the relay failed to energize or de-energize
when commanded by the computer. So either its not working, or its stuck on,
or the sensing circuit is faulty (check for corrosion on the under side of
the relay socket).

 

IF your battery gets LOW it also can trigger the 12. It can be just
low enough that it won't cause visible problems ,but if you cranked a
long time or left a light on or something to drain the battery. Yes,
even the fan may have stayed on abit to drain it.

 

Because contrary to popular belief, there are two
definitions for code 12 depending on how it is extracted.
Code 12 extracted via a scan tool means the battery has been
disconnected. (like-wise, a scan tool never reports a code
55 directly.)
Code 12 extracted via the method you used means "beginning
of fault code report." (55 = end of fault code report.)

No. Battery voltage is monitored by a different circuit.
Code 35 can indicate eother an open or a short, basically
it's telling you that the SBEC did not 'see' the anticipated
current value change across the driver that controls the fan
relay.

 

Ok, that explains the 12. I still can't find the reason for the 35.
Everything appears to be operating normally. Fans come on and go off in
relation to engine temp just like always before. No bad or corroded
connections were to be found. Ah well, I guess I'll just need to keep
looking.. This weekend I'll get the codes cleared and see if they come back.