4R70W tc not locking up all the time

[Dono]

I've been noticing that my rpm's on the highway are indicating that my tc isn't locking up all the time.

Im not sure whats different as I do the same drive every day, and some days the tc won't lock up. No codes, No head wind, flat......Whats going on? Is this correct?

[MENTION=81804]4pointslow[/MENTION] has a thread that is very helpful. http://www.explorerforum.com/forums/showthread.php?t=395226&page=2 Its a 5r55e, but I 'think' the pcm control is the same.

4pointslow, did you happen to run across the pid that commands the tc to lockup? Im not seeing it in my list of pids, although that does not mean its not there. The names of the pids can be a bit cryptic.

I'm also guessing that I'd be seeing a trans code if the pcm was commanding lockup, and the tc wasn't locking. So, if this is the case, what are the conditions the pcm looks for to command tc lockup?

 

[boominXplorer]

Are you running stock valve body? If so check out baumeen engineering, they make a great upgraded kit for the valve body for under $200. Torque converter lockup is night and day after. I recommend sticking with the stage 2 upgrades as stage 3 is pretty firm (what I did) and 4 and 5 are race only.

On a side note fluid condition does effect tc lockup but I'm guessing yours is pretty fresh.

 

[JK080]

The computer might not command lock up if the engine is not at operating temp. Missing or a stuck open thermostat can cause this.

 

[Dono]

The computer might not command lock up if the engine is not at operating temp. Missing or a stuck open thermostat can cause this.

Yes, I think the first step is for me to figure out what that pid name is that commands lockup and log it.
I do know the pid name for open loop/closed loop. I'll try to spend more time on it tonight.

 

[JK080]

The PID you're looking for should say "TCC" something, it may vary with scanners.

You can watch the TCC solenoid if you see that.

 

[4pointslow]

Tcc

Dono,
Are you using the X3 to datalog?
Also what is your PCM "strategy" number as read with the X3?
I will look up the TCC command for you if you have that number.

On Mine it is TCC_DUTY_CYCLE
May be the same on yours. If there are 2 "TCC_DUTY_CYCLE" listed just pick the first one.

If you have no idea what I am talking about let me know and I will post screenshots of LiveLink 6.5

To check for a stuck open thermostat let it idle and warm up, then drive it down the highway while having someone in the passenger seat watch the coolant temp sensor reading on the X3 or other scan tool, if it drops below the thermostat rating (195? F) then it is stuck open. I find most at 160 F when stuck open.

Brake light switch or TPS problems could also cause it but thermostat is more likely to cause it without setting codes.

Also are you driving down the road and then applying the brake to see if the RPM jumps up a few hundred RPM?

 

[Dono]

I'll get my strategy. I had no idea the name could change by strategy code. Wow.

Since Im not getting codes, I really do think the pcm is not commanding lockup very often.

Today going to work, no lockup at all. At about 65-70mph I am around 2000rpm in lockup, out of lockup I'm around 2500. I can also tell by either easing on the gas slightly more and seeing the tach climb instantly or touching the brake gently and the rpm's not jumping.

There is a big enough difference in rpm's between lockup and non-locked that it definitely affects gas mileage. Not to mention trans wear and heat.

Strategy is REAC4A2

I'm just plowing back some supper and I'll head out and pull the pids in to livelink

 

[4pointslow]

set up file

I made you a set up file with some good pids like coolant temp and TCC stuff.
I just emailed it to you.
Let me know if you have trouble using it, my instructions are half assed sometimes.

 

[Dono]

Ok, this is worthy of an 'OMG', or is it a 'WTF".

whats worse, in the time it took me to do this, 4pointslow already sent me a config file for logging. I guess that's what intelligence and knowledge does. Thanks!

Ok, lets see if I can get this config file loaded up.

 

[4pointslow]

Live Link

You are not using Live Link 6.5
You are using Live Link Gen2
May work but looks different and I made the file I sent with 6.5

 

[Dono]

I wen't for a quick test drive, and lockup isn't being commanded.
LOCKUP_DES_FLAG stays at 0. I'd think it should go high at some point.

On the test drive, I can confirm that the tc did not lock, even though I was at a consistent speed of about 65mph. Coolant temp was a average 193 degrees.

I'll have to keep reading on what stops tc's from locking up in the pcm.

I'm sure 4pointslow will be extremely helpful. I do find this one interesting(Yes, my truck is perfectly driveable).

 

[Dono]

I'll log on the way to work tomorrow.
I added some pids that might tell us whats flagging the pcm to tell the tc not to lock up.

 

[4pointslow]

Tcc

You can see in the picture that TCC duty cycle is never commanded. Sometimes "flags" like LOCKUP_DES_FLAG, don't work in Live Link. I found my flag for open/closed loop doesn't work. I also found way more problems with LiveLink Gen2 but SCT is working on it and every once in a while an update come out and more stuff starts to work. Gen2 has more pids available too, if they work.
That datalog proves the coolant temp is reaching 190F so no stuck open Thermostat. I wonder what the transmission temps are supposed to be on this transmission. It is running at 140 something.
Open and closed loop status would be another good pid to look at, if it works. Maybe LTFT and STFT too. There are a lot of more pids under trans in Gen2 I see from your screen shot so try them too. This is an interesting one.

 

[4pointslow]

Tcc

Try making a datalog from a cold start with Trans temp being datalogged. It should show it warming up as you drive it. If it stays the same temp all the time could be a bad Trans temp sensor or wiring etc.

Datalog the OSS or output shaft speed sensor if you can find it too.

And make sure the reverse lights come on in R.

 

[Turdle]

Want to see the TPS counts also.

 

[Dono]

Ok, reverse lights work.
I didn't have time to add TPS counts or look for output shaft sensor as I was rushed this morning (Like every morning).

I emailed the log to 4pointslow. Turdle, if you would like a copy I could send it to you also.

As 4pointslow pointed out, we don't even know if the pids I'm logging actually work.

I was hoping that the tc would go in to lockup on the drive to work at some point to see in the log what happened when lockup occurs, but it never did.

I'll add tps counts and hopefully find output shaft speed sensor for the drive home while logging.

 

[Turdle]

I believe the brake switch will also unlock the torque converter. Does your cruise control work normally?

 

[Dono]

I believe the brake switch will also unlock the torque converter. Does your cruise control work normally?

Yes, cruise works (at least it worked last time I checked), but I will confirm this on the way home tonight. Good thought.

 

[Turdle]

Another thing to try is to disconnect the battery to reset the PCM, then, go for a drive to see if the TC locks. Do this only as a last resort, and, yes I am going somewhere with this last suggestion.

 

[Dono]

ok, battery negative pulled (ill leave it off for the next couple of hours).
found and added OSS, and TPS Absolute for logging.

All bases are covered. I really wish I could confirm which pids are working. Maybe I'll get lucky and the tc will drop in to od while logging so we will know what the pids look like in lockup.

More to come after my drive home (At least part of it will be with the cruise control set).