2013 Transmission Severe Lock - momentarily and rarely

[Tom L]

I just got a 2013 XLT Premium with 53000 miles on it. I drove it 500 miles on a trip on day 1 and the transmission jerked the car rather severely 2 times. Both times I had reduced my speed such that I was not in the top gears and I was just starting to push the gas gently. It really slammed the car - as if it locked up for a quarter second or so. Other than that - it runs great - shifts fine, no slipping, and no noises.  I took it to the ford dealer and they checked and said there were no bulletins on it and that a connection of the vehicle to their computer showed no error codes. They also test drove it with no problem. As I'm fairly competent at car repair and also an engineer - I have a theory as to what is happening - but why is what the real problem is. As it operates perfectly 99.9% of the time - I have to determine what could cause such a violent jerk very rarely. All I can come up with is that the vehicle is downshifting when I slow down, and then upshifting as I start to accelerate.  My thought is that the transmission is actually going into 2 gears at once - momentarily. If you don't understand how an automatic transmission works, then don't reply that this is impossible or crazy.  I know there are clutches and bands in there that are engaged and disengaged with electric solenoids. A wiring problem could easily create total havoc in the transmission operation. I am guessing that I have one of 2 problems:

1, the solenoids are not energizing due to a wiring problem, connector, ..

2. a band or clutch is hanging up somehow and not properly disengaging  

So my questions are (and other theories are also being solicited)

1. exactly what does the computer monitor in the transmission

         are there sensors/switches that actually verify the solenoid positions or maybe just the voltage is monitored

         can the computer determine if the vehicle is actually going into 2 gears somehow - band or clutches hanging or energizing abnormally

2. does anyone have all the possible error codes for the transmission

3. does anyone have the wiring diagram for the transmission

4. where is the transmission computer

 

I'm assuming that my transmission is pretty much ok now - but it will self destruct with a few more of these severe jolts.

I'm open to any ides/suggestions

Thanks

Tom

[mrtn]

I have seen this happen with a bad throttle position sensor/wiring/connection. The computer gets a reading of a pedal fully depressed and reacts by kicking down two or more gears. Then self correcting again.

 

You can search for Focus codes as the Connects have the same drivetrain.

Edited March 2, 2018 by mrtn

[Tom L]

Thanks for the info!!  I will definitely check that first thing in the morning.  I would love it to be that simple as I really like the van otherwise. 

I’m not seeing any error codes or engine light.  Does the throttle position sensor problem you mentioned throw an error code?

Thanks

Tom

Edited March 3, 2018 by Tom L

[G B L]

If you get a good grade scanner and record a drive  the shift history should provide valuable information.  I do not have any experience with  a gen 1 but if it has a drive by wire throttle the pedal should be checked also.

[Tom L]

I pick the part up this afternoon Motorcraft sensor.  I’ve learned my lesson multiple times on the off brand stuff.  

After thinking about it - the sensor could easily cause exactly what I’m am experiencing. I’ll check throttle this sfternoon also. 

Thanks again!!!!

tom

 

 

[mrtn]

Throttle position sensor would not throw an error code as any reading within the accepted range is good. It may not be good in relation to real life condition but mathematically it’s sound.

[Tom L]

I put the new sensor in this morning - now the wait begins to see if the problem reoccurs.   This generation has the sensor attached to the throttle body - not drive by wire. I just replaced the sensor itself instead of the entire assembly.  I saw a video where a guy replaced the entire assembly.  I was thinking that this sensor would not throw an error with the sensor detecting the accelerator floored as that would be a normal condition.  It would also be within normal possibilities to floor the car and immediately let up - start to pass on a two lane road and the see an oncoming vehicle.  In my case it amounted to an instant downshift at a rather low rpm - causing a severe brake feeling. 

[mrtn]

I thought the TPS is integrated in the accel pedal itself as it is in the diesel models in Europe. It's known to fail occasionally.

[Tom L]

This one is tied to the air intake. 

 

[G B L]

That is a good video, The throttle is by wire there is an electric throttle module on the top of the accelerator pedal that signals the throttle body how much to open.  If what you changed does not solve the issue the pedal signal could still be a cause.  If you have a data view scanner you can check the throttle signal from the pedal

[mrtn]

Some kind of data logger would help a lot.

[Tom L]

What is a good reasonable data logger model?  In the event I need to check that. 

Thanks

tom

[mrtn]

I guess ELM327 + Forscan is the tool of choice usually.

[Tom L]

I was thinking on my problem last night - as  it is somewhat nerve wracking to drive and think the car can slam into a lower gear at will. Anyhow - if the problem was related to the accelerator position sensor, that could explain my problem.  But - this should also accelerate the engine.  It would also really be bad for ford - if a simple single sensor could accerate the vehicle without warning. I would assume there are 2 sensors in there - and any hint of a discrepancy  would throw an error code. Of course, I could be wrong as I’m definately no expert on this

tom

[Tom L]

I’ll order one of those scan tools when I get home again. That is definitely cheap enough to purchase. 

Tom

[Tom L]

I found the schematic - there are two sensors in the accerator position sensor. Image attached..

[mrtn]

4 hours ago, Tom L said:

I’ll order one of those scan tools when I get home again. That is definitely cheap enough to purchase. 

Tom

 

Found a warning on Forscan site that some ELM327 clones are not manufactured to specs and miss some features. Read up.

 

Regarding acceleration: no, as the butterfly does not move and there’s no extra oxygen available the car cannot accelerate. The injectors may squirt some extra fuel for a split second but it has no effect as the fuel mixture is way off. One thing to analyze as well.

Edited March 5, 2018 by mrtn

[PhotoAl]

I purchased this OBD interface from Amazon for $29.99.  It worked without a problem for me but some have had issues with it.  https://www.amazon.com/gp/product/B01F0GVBWY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

I'm running Windows 7 64 bit on a Dell notebook and let it install the drivers it wanted when I plugged the device into the USB port - it was not plugged into the OBD port at the time.  It did take a couple of attempts fiddling with the switch on the box to get it to work.  I think one position is a demo mode or something.

[Tom L]

“Regarding acceleration: no, as the butterfly does not move”.  

 

So, the butterfly is also opened by the accelerator pedal? It’s raining here or I’d look under the hood.    On my sons Honda - the accelerator does not move the butterfly - which I considered to be what ‘drive by wire’ means.  That’s the first I’d ever seen like that.  I’m more old school - rebuilt a lot of engines in the 60’s, then single body injection, then early Explorers where there is no accelerator position - other than the butterfly sensor

[G B L]

The diagram shows the engine sensor actuator and the  actuator run by the foot petal

Edited March 6, 2018 by G B L

[mrtn]

On 3/4/2018 at 8:05 PM, Tom L said:

This generation has the sensor attached to the throttle body - not drive by wire.

 

On 3/6/2018 at 12:37 AM, Tom L said:

So, the butterfly is also opened by the accelerator pedal? It’s raining here or I’d look under the hood.    On my sons Honda - the accelerator does not move the butterfly - which I considered to be what ‘drive by wire’ means.

 

I don't know, I'm just following your discoveries.

[G B L]

If you look at the Video on the changing of the Throttle body that you posted , when the throttle body is removed the tech only disconnects the wiring harness and the bolts. There was no throttle cable , it must be drive by wire.

[Tom L]

Sorry for delay - been traveling.  I’m up to 1500 miles now with no problem. Yep -  I looked at mine last night and when I depress the accelerator, nothing under the hood moves. 

I feel much better now driving it - not expecting a jolt without notice at any moment. 

Tom

[Tom L]

Update. I have around 5 k miles now on the van and have had no further problems.  Thanks to all who replied and helped - I don’t think I could have found this problems fix on my own

tom