2008 Sorento EX Transmission not downshifting under throttle.

1471 Views 24 Replies 6 Participants Last post by Yogi-4, 6 d ago

mmccarrell

Discussion Starter · 3 mo ago (Edited)

Edit - I'm in the US so it's the V6 gasoline engine.

I recently bought a Sorrento with 176K miles on it. It's part time 4x4 and it won't down shift when I mash the pedal or go up a hill. The trans shifts normally in auto mode only from a stop. It is maybe a bit to quickly to get in to 4th or 5th but it does it on it's own. However once in 4th or 5th it won't downshift. I can floor it and it does nothing. The ESC off light is lit.

I can manually shift the truck without any problem I can tell. Both up and down work just fine.

There had been a CEL for a lean condition (P0171 - P2187) that I believe I sorted out buy checking the intake for leaks and cleaning the crap out of the throttle plate.

Also there is no 4x4 right now. When I switch to 4 hi (trans in neutral) nothing happens. When I switch to 4lo the 4 low light blinks and still no 4 wheel drive.

I've reset the whole truck by disconnecting the battery for a few hours and I also reset the trans a few hours later by removing the fuse.

I tried to check the TPS but it's not like one I've ever seen. It has 8 pins I think and looks like it also has the throttle actuator on the same connector. What's up with the coolant line to the throttle body anyhow? There isn't any trans codes or my cheap scanner can't read them I shows "No codes found" when I select the A/T section.

Any thoughts or suggestions are welcome.

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gee6

· #2 · 3 mo ago

May or may not be relevant: I have previously seen "Esc OFF" + "no 4wd" reported as an abs wheel sensor issue. You would probably have to diagnose each wheel sensor (unless it is obvious!) without any other clues to guide you. I can't remember if there was a satisfactory conclusion. However, with other issues present it could be something else entirely........

mmccarrell

Discussion Starter · #3 · 3 mo ago

gee6 said:
May or may not be relevant: I have previously seen "Esc OFF" + "no 4wd" reported as an abs wheel sensor issue. You would probably have to diagnose each wheel sensor (unless it is obvious!) without any other clues to guide you. I can't remember if there was a satisfactory conclusion. However, with other issues present it could be something else entirely........

I can totally see that being the case for the 4x4 but I'm not sure how that could affect down shifts but I certainly won't say honest to goodness.

Is there a scanner use regular shade tree wrenchers can afford that will scan ABS? I'd have thought the ECM would have codes for that.

gee6

· #4 · 3 mo ago

mmccarrell said:
I'd have thought the ECM would have codes for that.

Agreed, but not sure on that.

Yogi-4

· #5 · 3 mo ago

I'm actually in the same exact situation. ESC OFF light is on and no 4X4. No power going up hill like it's stuck in one gear. I'm using a Bluetooth OBD2 adapter and getting the error code P1739. Evidently it has something to do with the transmission. As far as I've been able to research, (so far) it may be a shift solenoid. I've got lots of critters around here, so I'm gonna look at the wiring and see if something tried to munch down on some wires. Hopefully it's something that easy, worse case is pulling the trans pan and testing the solenoids, one, by, one. I haven't tried using the sport shift yet.

leo42.2875

· #6 · 3 mo ago

P1739 - Kia Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis (dtcdecode.com)

DTC KIA P1739 Short Explanation - Bing video

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mmccarrell

Discussion Starter · #7 · 3 mo ago

Yogi-4 said:
I'm actually in the same exact situation. ESC OFF light is on and no 4X4. No power going up hill like it's stuck in one gear. I'm using a Bluetooth OBD2 adapter and getting the error code P1739. Evidently it has something to do with the transmission. As far as I've been able to research, (so far) it may be a shift solenoid. I've got lots of critters around here, so I'm gonna look at the wiring and see if something tried to munch down on some wires. Hopefully it's something that easy, worse case is pulling the trans pan and testing the solenoids, one, by, one. I haven't tried using the sport shift yet.

What has me confused is the lack of any code other than the lean condition. I'm planning to check the wiring also since who knows what gremlins could be lurking about in there on a truck this old. I've seen some crazy things in wiring before.

Yogi-4

· #8 · 3 mo ago (Edited)

Did you clear those old codes and try again?? Weird that we have exact same symptoms, but we have different fault codes. I checked and found no gremlins chewing at the wires.

Edit: I did find where in my case, the transfer case isn't getting the signal from one of the ABS systems (front or rear). Things are starting to point towards the motor on the transfer case or the actual EMC is bad. Also, it looks like we're both in 'Fail-Safe' mode.

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mmccarrell

Discussion Starter · #9 · 3 mo ago

Sure did. I drove around for a few miles after clearing the codes and cleaning the throttle body and nothing has set again. It just refuses to downshift. I will down shift when I come to a stop and then start again but it won't kick down so to speak. The 4x4 still doesn't work and the only light on is the ESC OFF light.

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Lou O.

· #10 · 3 mo ago

Something is telling it not to downshift when in auto mode, because you verified in manual mode it will shift thru all gears.
Might be a speed output sensor acting up. Has the trans fluid been changed? You might try taking it to a parts store that can put a code reader on and see if any codes exist. Or, take it to a trusted mechanic and see what they have to say....Keep us in the loop please, and good luck!

mmccarrell

Discussion Starter · #11 · 3 mo ago

Lou O. said:
Something is telling it not to downshift when in auto mode, because you verified in manual mode it will shift thru all gears. Might be a speed output sensor acting up. Has the trans fluid been changed? You might try taking it to a parts store that can put a code reader on and see if any codes exist. Or, take it to a trusted mechanic and see what they have to say....Keep us in the loop please, and good luck!

I'm leaning toward a mechanic but it's hard to have one I trust since I do nearly all my own work. I might pay the dealer to run the diagnostics and go from there. I got a few other things to check first.

CochiseG

· #12 · 3 mo ago

If ESC is on, then the car is in limp mode so you wont have access to some on the transmission function/gears. try to screw the gascap on with a click

mmccarrell

Discussion Starter · #13 · 3 mo ago

CochiseG said:
If ESC is on, then the car is in limp mode so you wont have access to some on the transmission function/gears. try to screw the gascap on with a click

Gas cap was one of the first things I thought about and did check it. The check engine light isn't on now. Other than the ESC OFF light and it not having 4x4 or downshift everything seems OK.

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Yogi-4

· #14 · 3 mo ago

Welp, I fixed it... kinda. Since I don't have the time or weather at the moment to do a complete wire check, I removed the TCCS fuse. I now only have rear-wheel drive and the transmission shifts as it should... BUT... I lost SAFETY features. So do this at your own risk. I lost ABS and my dash lit up like a Christmas tree, but it drives and shifts as it should, so it is no longer in 'Fail-Safe' mode. The fuse panel is by the driver's left foot. This will be fine for me until I can get to diagnosing it properly. Hope this helps and drive SAFE.
Also, during my internet scavenger hunt for answers, I did find a piece of info that could help others. It's a PDF explaining the TOD system along with wiring diagrams and code meanings like I posted earlier. I'd give credit to whomever or wherever I got it from, but I had so many tabs open it's impossible to recall.

mmccarrell

Discussion Starter · #15 · 3 mo ago

Yogi-4 said:
Welp, I fixed it... kinda. Since I don't have the time or weather at the moment to do a complete wire check, I removed the TCCS fuse.

That is an interesting idea to disable TCCS at the fuse. I'm curious if this "fixes" mine. I'll have to check and see. Obviously I want a permanent fix and will post back here when I find one. I hope I find one.

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gee6

· #16 · 3 mo ago

Removing TCCS fuse (14) disables the transfer case but, with the facelift (2006.5+) you do loose other feature. That is why it is reserved for pre-facelift as a recommendation except for testing. The P1739 (et al) specifically relate to an issue with the shift motor mounted on the transfer case so disabling the transfer case electronics perfectly explains the "fix" in those circumstances. The issue still exits, unfortunately.

mmccarrell said:
That is an interesting idea to disable TCCS

But, as observed, without the pointer (P1739 or similar) it is not obvious that it would be a similar solution.

Yogi-4

· #17 · 14 d ago

Just to give an update on my P1793 code. I pulled the motor off the transfer case to check it with a multimeter. Watching a YouTube video on how to do it, I can't remember the exact ohms, I think it was supposed to be in the ballpark of 4 ohms. Mine was reading 40 something. So I ordered a new one. HINT: shop around, as I got a TRQ brand (new, not rebuilt) for under $100 shipped. I changed the fluid in it. Good thing because it was black. And there was no way 1.5 quarts was in it, more like 3/4 of a quart. And yes, you'll have to take the dampeners off (the 2 round weight thingies beside the motor) in order to get to the fill plug. Take out the FILL plug FIRST before even touching the drain plug. If for some reason you can't get the fill plug out, and you've already drained it, you're toast. My plugs had Teflon tape on them, so evidently someone was in there already. I put tape on the plugs and filled it back up. I just used Valvoline Maxlife ATF. Put the old motor back on, put the TCCS fuse back in and fired it up. Holy crap, it worked!! No more error lights!! But it only lasted a couple of days. I will say, it does drive quieter now. The new motor came in yesterday and I replaced it. It just has 4, 10 mm bolts and the wire connector. I could not, for the life of me, figure out how to undo that connector!! Let's just say that I've might have said a cuss word or 20. I got it back together and secured (with zip ties). But now when I put it into 4 High, the drive train light flashes and in 4 Low, the 4 Low light flashes. Thinking maybe it's that little compressor by the battery. But that's to be diagnosed on another day. I hope this helps someone.

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mmccarrell

Discussion Starter · #18 · 6 d ago

It's appreciated. I've got a bit of an update myself. I took it to a shop and they diagnosed it as a fail output shaft sensor but were unable to do the work to replace it. Apparently you take the transfer case out to get to it so that will be fun. It's looking like I'm doing this one myself since no one wants my money and I'm screwed on the vehicle so I'll break out the tools. Anyhow another shop pulled all the codes for me and here they are

ABS system
C1627 CAN Time-out 4wd
C2112 Valve Relay
C2402 Motor electrical

4wd system
U010 ECU ITM Malfunction
P1739 General Position Encoder Fault

So I think I'll get an encoder motor first and see what that does for me. I need to find a way to pull all the codes for myself too since I can't afford to get the codes run at the shop all the time.

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gee6

· #19 · 6 d ago

Not sure how they get from those codes to their diagnosis

If there is a problem with the output shaft sensor, before you pull the transfer case completely, drop the propshaft at the T/C. Check for play (fore and aft) in the T/C yoke. This is held on by a staked not so should not come loose, but it has been known. This allows the sensor ring to move and cause issues. (Typically symptom is a bouncing speedo needle). You never know.

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mmccarrell

Discussion Starter · #20 · 6 d ago

gee6 said:
Not sure how they get from those codes to their diagnosis

The shop fellow said that when he drove it he saw no reading from the output shaft sensor and was confident enough to order the part.

What loses me is the other codes and that they are from different systems. I guess if the wiring is buggered it could be doing funky things and I'm going to check all the grounds for sure.

I'll check the yoke but the speedo is stable so I doubt it but it's worth looking before doing anything crazy. I'm not looking forward to pull the case but if that's what it takes. It's not like I can find someone who wants my money right now. The blows my mind. I've called about a dozen shops and they all are either not interested or "we can get to it in September"

I'm getting tired of this economy right now. Whole damned world seems turned upside down. I'll keep updating though. Maybe my struggle will help someone else. Thank you for the suggestions and keep them coming if you don't mind.

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