P1795 code - 00 Kia Sportage

[beej67]

My car is showing 2 codes:
P1624 Mil request signal from TCM to ECH
P1795 4WD switch signal malfunction
gives probable causes:
1. Open or short circuit condition
2. Poor electrical connection
3. Failed 4WD low switch
The vehicle has recently had a new battery installed and a new fuse for the brain (I assume the computer, thats just what someone called it to me). Ran fine for 2 weeks and now the hold light is flashing and the check engine light is on and the vehicle is rough running.
The vehicle also has about 80K and we've never changed the timing belt. From reading various posts here, I'm guessing we should do that soon also.
Any suggestions of where to start on this? Thanks in advance for your help.

[LMP]

Originally Posted by beej67

P1624 Mil request signal from TCM to ECH
P1795 4WD switch signal malfunction
Ran fine for 2 weeks and now the hold light is flashing and the check engine light is on and the vehicle is rough running.

1624 just tells a code has been sent...and this code is 1795, and you have properly identified the cause. ...and all of this keeps the HOLD light flashing and the CEL ON....SO check under for wiring to transfer case switch..otherwise this is not a real cause for concern...unless some speed or rpm limitation applies by cutting ignition when 4low is detected...not sure of that assertion but a possibility. So better clean that problem ASAP.
http://i250.photobucket.com/albums/g.../lowswitch.gif
http://www.avigex.ca/kia/P1795.pdf
Why was it necessary to change the fuse for the "brain" ?????

except for the above "assertion", rough running would not be related to the above....and spark problems generally pop codes very easily..so keep checking for other relevant codes. Without codes, it is more trial and error....
If you are talking in miles,80,000 is indeed time for, at least, preventive maintenance.
About rough running, lets have it with more details: rough idle can be related to idle air valve sticking, as some have reported, ; just clean it. If it gets "rough" only when accelerating, spark can be a problem....
So....the basics : spark plugs, spark plug wires, coils ,must be cleared before looking for the complicated. These elements are really sensitive on this engine, and oil contamination on 4th (rear) spark plug is common. Valve cover gasket leakage is a common issue.
www.geocities.com/lmp4203/kiasport/kiatop.JPG
www.avigex.ca/kia/gasket1.JPG
www.avigex.ca/kia/gasket2.JPG
www.avigex.ca/kia/gasket3.JPG
If you already have the CEL ON, another code can come....and go without your knowing, so check codes frequently, right after any "incident".