So I acquired a free 2008 Kia Sedona but with all free cars you get free problems. So here we go. The previous owners son attempted to jumpstart the van and reversed the positive and the negative, not good, and this has caused some problems. The main one being that the transmission will not shift out of 3rd gear when I am in drive no matter what I do, I think it is in limp home mode. Unfortunately the issues don't end there. The OBD2 scan tools that my dad has will not connect to the van but they will connect to every other vehicle in the driveway. The previous owner in order to fix the issues assumed that the ECU was dead and ordered a new one but did nor get the ECU flashed to the VIN number. He also replaced the fuse box with a new one.
Here is what I have done so far. I have checked all the fuses under the dash and under the hood and tested them with a meter. I have checked the ECU plugs and the fuse block plugs for bent pins and or bad connections.
Unfortunately it has started to rain on me so I am stopped for a bit. So here I am GRM looking for some help. I usually let my old man (Toyman01) handle the posts on here but I figured I would try my hand at this one.
Bumping this for the week-day crowd.
To bring it up to date, we have been through every fuse in all three fuse blocks, replaced the IPM under the dash, tested an assortment of wiring, and got nowhere. The PO replaced the ECU. We have also pulled the ECU plugs and checked them for corrosion and bent pins. No luck.
The car starts and runs perfectly. All lighting works. The radio works. All the power windows work. All the power doors work. The speedo and tach work. The only problem it has is it won't shift. It starts off in 3rd and stays in 3rd. It has a CEL and ABS light on. I am assuming because of the speed sensors on the transmission, but without access to the OBD2 system I have no way to know.
Neither one of my OBD2 scanners will connect to the ECM. Doing some reading, we are supposed to be getting between 60 and 120 ohms of resistance on the data lines at the OBD2 port. We have nothing. The rest of the day was spent digging through the wiring diagrams to see where those wires go. No luck so far.
Kia has another diagnostics port under the hood that appears to have the same data lines. We have ordered an adapter to try to access the ECU through that port. It should be in today.
The transmission sensors are only $14 each so they have been ordered as well and will be installed to see if that takes care of the transmission problems. They should also be in today.
If anyone has access to the wiring diagram for the OBD2 port, that would be appreciated. The only thing I can find is a diagram that shows the data lines going to J/C M12, which I assume is a junction connector or similar.
If anyone has any other ideas, they would be appreciated as well.
Probably not much help, but is there a chance that the transmission control module is not "paired" to the new ecu?
What are the chances of getting a hold of the factory ecu?
I would swing by a Kia dealership and try to talk to one of the techs. Bounce it off of them and see if its worth bringing it in to assign the ECU to the car. Might be cheap.
I read this, not sure it applies here but it was interesting enough to post:
"
The TCM (transmission control module) is located in the ECM (engine control module) and it gets information about what "gear" you select (DRN12) from a "range" switch located on the top of the transmission... This switch is moved every time you move the gear select lever.... This switch also provides the power to the reverse (back up) lights.... (your original problem)... The Mechanic probably removed and cleaned this switch... If this switch is not properly aligned the TCM may get confused as to what selected "gear" you want and may throw the transmission into what is called a "limp" mode (third gear ONLY) until you put the car into "park" and restart it..."
MY first thought was incorrect ecm or not properly programmed.
In reply to bobzilla :
Slippery, The factory ECM for the car was thrown away. No comment on that. 
Correct, the TCM is in the ECU. Checking that series of switches is on the list while we are replacing the speed sensors.
Bob, that was my first thought as well, but from my reading, the ECU on this particular car doesn't need to be flashed with the VIN. This car doesn't have any anti-theft and the engine starts and it drives fine other than the transmission issue.
In reply to Toyman01 + Sized and :
mY OTHER THOUGHT IS wrong PCM? Right for the engine enough to run, wrong pins for the harness and trans? HArd to know since they pitched the old ECU. You might take the VIN and go onto the Kia parts sites and get the PCM part number and compare it to the one you have to verify
Bob once mentioned to me that Kia wa known for a lot of mid-model run parts changes. This often required VIN to look up parts. This makes me wonder what was this PCM sourced from? As Bob eludes to the Sedona and Sorento used the same engine but does this make the PCMs interchangable?
Were there any transmission changes during the product run?
Seems that your body style ran from 2006 - 2012. The 2006-10 are all 3.8L w/ 5 speed automatic. For 2011 the body stays the same but 3.5L and 6 speed automatic????
Aside from that, there could even be changes from '06-'10
All good thoughts and worth looking into. Thanks.
I know when I was looking at a second ECU for my tuned forte, there were 4 VIN breaks for a 2010 2.4 Manual
After doing some digging, it looks like all the Sedonas from 06-09 use the same ECU part number.
After doing some digging, changing the speed sensors on the trans, and using an adapter to plug into the Kia diagnostics port under the hood, we are exactly where we were before. Still won't shift out of 3rd. Still can't connect to the ECU.
Tomorrow the plan is to dig under the dash and find the J/C M12, whatever that is.
With all due respect to you trying to fix it on your own, why not pay the 1 hour diag time to a neighboring Kia dealership to diagnose it for you? Seems like the simplest and most pragmatic solution.
In reply to Loweguy5 (Forum Supporter) :
That is an option. But not much fun. 
We actually discussed doing that this afternoon. We aren't quite to that point yet.
I know I know, it's not a fun option. But in my estimation working on a Sedona isn't much fun either.
In reply to Loweguy5 (Forum Supporter) :
I enjoy anything I haven't done before. It's the every day stuff that bores me to tears.
And with a few spare cars we aren't in a big rush to get it on the road.
So, this morning we went back to LKQ and picked up the front area module and the ECU out of the van we pulled the interior module from. The assumption being if it was a vin issue changing all the modules would solve it. Also if it was an ecu issue it would be solved as well.
The OBD port now works correctly and the transmission shifts as it should.
Total cash outlay, $100. Total time spent, about 10 hours.
I think it's going to be a pretty decent van considering. It only has about 140k on it and is in pretty good shape. Well worth the $100 in parts and the time.
Needless to say, my son is super stoked we got it figured out. His only complaint about it so far is it is only rated to tow 1000 pounds.
