Hey there. I have been noticing that every once in a while my 2004 V8 will not lock up the torque convertor. it happens when the cruise is on and going down hills then hitting the other side. passing people once in a while. If I leave the cruise on and throw it into 4th it shifts like it is supposed to and I can tell it locks then. i will put it back in 5th and it locks up like supposed to. Playing around I noticed that this does NOT happen at all if I do not use the cruise. I have put MANY miles on playing with this now and have figured out that much. There are not any idiot lights on inside or anything and it runs great in every other aspect. This is just annoying. Do you have any ideas?!?! Thank you in advance!!
Annoying cruise issue
- Thread starter luvmyt4r
- Start date
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That is correct. It performs flawlessly when I do not use the cruise. When I am using the cruise is when it acts up. So that is why I was trying to figure out how it is run. hmmmm. Vacumm huh? Maybe a plugged or leaking hose? I am just grabing for ideas here. What if there is a loose connection somewhere? Where is the ECU on these? I JUST bought it a couple of months ago, so I am trying to find things yet.
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No, not vacuum controlled. Older vehicles were vacuum run, wire pulled, method. The systems were always going out. The pump would die, the tube would leak.
Now, most are pure electrically controlled. Toyota, as with most makers, have moved toward none cable controlled throttle. The ECU directly controls it via the pedal position sensor or the cruise control.
As for why your truck would NOT be locking up in cruise control is beyond me. Toyota has an adaptive learning system for throttle response. It could be that the computer "thinks" it is best anticipating your needs?
Now, most are pure electrically controlled. Toyota, as with most makers, have moved toward none cable controlled throttle. The ECU directly controls it via the pedal position sensor or the cruise control.
As for why your truck would NOT be locking up in cruise control is beyond me. Toyota has an adaptive learning system for throttle response. It could be that the computer "thinks" it is best anticipating your needs?
Yea. Man, that is tough. I k now mechanics... but unless you are a Toyota tech or engineer, beginning to figure out the software in the ECU that is being used to determine the cruise control relationship to the transmission lock up... ick. Beyond me.
I do know that you can pull a fuse and "restart" that adaptive learning. Essentially send your 4runner back to kindergarten.
Perhaps doing this will change how the ECU controls cruise. Obviously, if the tranny is working flawlessly when not in cruise control, then it doesn't sound mechanical. It sounds software... and ICK, good luck with that.
Maybe one of our helpful toyota dealer techs on here can help...
I do know that you can pull a fuse and "restart" that adaptive learning. Essentially send your 4runner back to kindergarten.
Perhaps doing this will change how the ECU controls cruise. Obviously, if the tranny is working flawlessly when not in cruise control, then it doesn't sound mechanical. It sounds software... and ICK, good luck with that.
Maybe one of our helpful toyota dealer techs on here can help...
rtuck1
New member
I have the same exact problem and have yet to figure it out. My buddy has a lexus ls430 and it did the same lexus first replaced the transmission and then replaced the tcm which fixed his issue. I have learned to live with it.
For the record I did search. Thanks for jumping on me right of way. I apprecate how people jump there right of way and expend the energy into typing that rather than giving some REAL advice. If you are the pro of it...how about posting a link then? Thank you very much for your help!
Learn to google bro.
http://www.toyota-4runner.org/probl...en-torque-converter-cruise-control-issue.html
http://www.toyota-4runner.org/4th-gen-t4rs/13473-creeping-tach-while-cruise.html
http://www.toyota-4runner.org/maintenance/8769-torque-converter-lockup.html
http://www.toyota-4runner.org/4th-gen-t4rs/22622-lock-up-torque-converter.html
kthxbye
Acidmeld
New member
I thought I would throw in my two cents on this one. The torque converter unlocking on any sort of grade is completely normal. Going uphill it unlocks to give the transmission more torque before attempting to shift down to fourth gear. The torque converter is simply designed for fuel mileage on a flat cruising surface.
TRUE. You are correct....But it SHOULD lock back up on its own also. THAT is the issue I am having. I think I need to say this also. I worked on cars for 16 years before this carreer. SO....I know what the TC is supposed to do and how it is supposed to work. I am trying to figure out why mine isnt doing what it is supposed to be doing. There. That is my disclaimer. So please before I get told anymore what the TC is supposed to be doing....I know that. Read a bit more carefully please and see what mine is NOT doing. Thank you.
Nope. Unhooking the battery didnt have it relearn anything....next idea?
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Acidmeld
New member
I've been doing this career for 5 years, went to UTI and Toyota advanced education, and I can tell you that what you learned about transmissions 10-15 years ago means absolutely nothing in relation to how they are operated now. I constantly am having to explain the differences to the older guys in the shop.
That being said I can expand on my last post. The torque converter will not relock because the ECM now believes that the hilly terrain is going to continue. Since it thinks that it is going to have to unlock the tc soon it attempts to reduce wear by not locking. This is an attempt by the engineers to be smarter than the driver. Whether it works or not has yet to be seen but since the trannys are lasting pretty much forever I'd say it's doing pretty good.
End of rant. My apologies to the innocent bystanders.
That being said I can expand on my last post. The torque converter will not relock because the ECM now believes that the hilly terrain is going to continue. Since it thinks that it is going to have to unlock the tc soon it attempts to reduce wear by not locking. This is an attempt by the engineers to be smarter than the driver. Whether it works or not has yet to be seen but since the trannys are lasting pretty much forever I'd say it's doing pretty good.
End of rant. My apologies to the innocent bystanders.
rtuck1
New member
I do understand what you are saying and how this is supposed to work. However, the truck does not do this when i, the driver, have my foot on the throttle. This only happens when cruise is engaged. If anything it should happen less when the cruise control is engaged because the computer is choosing the throttle position etc. Just my thoughts, i could be way off base.
BOTH are very valid points. Thank you. I do have a 3 hour drive tomorrow, maybe I will just leave it and see if it does lock back up on its own. If it doesnt....then not sure where to go.
BY the way. I didnt mean to come across as a #$!#$. I am just tired of people on here jumping at the search and then also answering in the extreme simplest way. NOT saying you did. I didnt mean it like that, just saying. I also JUST got out of working on cars about 1.5 years ago.
Thank you though and I DO mean that.
Acidmeld
New member
I also JUST got out of working on cars about 1.5 years ago.
I don't blame you. It's become a **** industry to be in. Seems like the more training I get the harder I have to work for less money. Gets frustrating.
