2010 TC transmission/torque converter acting erratic

[Matt416]

I have a 2010 TC, basic model, with about 81,000 miles. I changed the ATF 9,000 miles ago. I have not had any transmission issued up until this point. Transmission fluid still looks clean and full. But now this happened:

 

Thurs 5/12 - early morning on the freeway, torque converter clutch would not lock up in 4th gear, RPM too high for 4th gear going 65 mph (shifting had been 'harsh' on and off for a few days). Orange wrench light came on, OBD2 said pending fault P0741. Went home, found oil in the 9-pin plug that goes into the transaxle. Cleaned out oil and did not find any wire damage. Everything seemed to work fine for a few days, drove roughly 150 miles.

 

Tues 5/17 - afternoon, now the torque converter clutch was not disengaging, so slowing down to idle the engine would die. Also died in reverse (engine runs and idles perfectly). No error codes found. Cleaned the plug again even though it looked clean, and vehicle idled fine in drive and reverse.

 

Wed 5/18 - early morning on the freeway, shifted fine but torque converter clutch would not lock up in 4th gear (RPM too high for 4th gear going 65 mph). Tried disengaging and engaging the overdrive button, and the overdrive-off light came on the first few times, but then would not come on again. Got off the freeway and then back on to go home, shifted manually into 1st, 2nd, and then drive (shifting was not very smooth), but the vehicle would not go into 4th (overdrive). Kept trying the overdrive button, the overdrive-off dash light never came on, and eventually the vehicle went into 4th gear but the torque converter clutch was still not engaged. 

 

Took apart the 9-pin connector, put it back together, double-checked all wires, everything looked good. Test drove in the afternoon, started out on the freeway okay, a little rough shifting, overdrive-off light was working, went into 4th and the torque converter clutch locked in for a little while, then disengaged. The wrench light came on. Got off freeway, drove around the neighborhood, motor did not run rough or die at stops with the transmission in drive, and the wrench light went off. Back on the freeway it would not go into 4th for a while, I tried hitting the overdrive button several times, but the overdrive-off light on the dash would not come on. Got off the freeway, drove around the neighborhood, turned engine off then on, now the overdrive-off light was working, got back on the freeway, now it shifted into 4th but clutch still did not lock up.

 

I am finding this very frustrating. My gut feeling is this is an electrical/computer problem. According to the shop manual (and tracing the wires) there is no transmission module. The PCM controls the transmission entirely. I thought it might be a solenoid in the transmission, but as far as I can tell, there is no specific solenoid in the transmission that controls the torque converter clutch engagement. Any ideas for what to try next would be greatly appreciated!

 

Thanks in advance,

Matt

 

Edited May 20, 2022 by Matt416
typos

[Matt416]

I am still perplexed by how the torque converter clutch is directly controlled. The PCM decides when it should be engaged or disengaged, but I can’t find a specific solenoid, or even an electrical circuit to actually operate the engaging or disengaging of the torque converter clutch. Any ideas?

[G B L]

There must be a solenoid in the Transmission that controls the TCC, I don't have your diagram but there is a solenoid!

You need an upper end Scan tool or Fortrans to make progress.

[Matt416]

I totally agree that there should be a solenoid that controls the torque converter clutch. When I look in my big Ford workshop manual, it has loads of information, but nowhere can I find a TCC solenoid in the transmission. There is a diagram that shows six solenoids, and the description of each don't remotely sound like they would control the TCC. There is also a description of nine wires to the main transmission plug, but again, nothing sounds like it controls the TCC. If I could figure out which solenoid it is, I can then figure out which wire it is and tap into it. I could run that wire into the cab with a voltmeter, then drive around and see if it is the PCM is working intermittently, or if the problem is something else downstream. I've ordered an OBD2 that works with Forscan, so I'll see if that helps. I've attached three photos.

 

Matt

 

[G B L]

Sounds like the two solenoids that control 3 and 4 work in tandem with  a speed sensor to allow the TTC to lock up.

I wonder if there is a kit that contains all the solenoids .  That would allow you to drop the pan and replace all the parts  at once .

The forscan will help.

[Matt416]

I hooked up Forscan and started recording with a laptop, and of course, now the Transit has been running perfectly. So yesterday morning, on the way back I decided to unplug the OBD2 but have the laptop all ready to go. After about 15 minutes of driving on the freeway (flat, 65-70 mph, 4th gear) the TCC unlocked, so I plugged in the OBD2 and started recording. After another 5 minutes of driving, the Transit downshifted to 3rd and stayed there. I tried hitting the overdrive button on and off, but it didn't make a difference. I got off the freeway, stopped, and reviewed the recordings. The OBD2 output agrees with what I observed (the TCC disengaging and the shifting to 3rd gear). I reviewed the options of what could be shown with Forscan, and added a few more to record. I went for another couple of drives after that, but now of course the Transit is running perfectly again. For me, with my limited experience with computer-dependent vehicles, this problem is pointing toward an intermittent PCM problem. I will be out of town until August. When I get back I will try this all over again.

 

Matt

[G B L]

Can you control the transmission solenoids with the Forscan? If so see if they all cycle.

It could be the PCM but a weak solenoid could also cause the condition.

Waiting to hear more in August.

[Matt416]

Hi GBL,

 

   Sorry I have not reported in sooner. I got back in August, drove around with Forscan, and of course the torque converter clutch was working perfectly. Overall, the shifting is better, but not great. It is a little harsh shifting once-in-a-while, and doesn't upshift as smoothly as it used to. The oil is still clean, so I doubt that there is any mechanical issue within the transmission. I went ahead and ordered a new PCM from Flagship One (I know, they don't have the best reviews). I made it very clear to them that I do not have PATS, no chipped keys. They said it would by 'plug and play' (ha ha). I installed it, and my Transit would not start (would not even turn over). I used Forscan, and got an error code B2139 - "The PCM identification was not recognized by the PATS module”. In the workshop manual, it says that if a PCM is replaced, "the parameters MUST be reset in both modules, or the vehicle experiences a PATS no-start. This occurs even if the vehicle is not equipped with PATS." The manual then continues to describe how to reprogram chipped keys. It also says "From the scan tool, follow the onscreen instructions to ENTER SECURITY ACCESS." Is this something I can do with basic Forscan? and not screw things up?

 

Matt