Shifting problem

Photo and video uploaded as further documentation.

Good afternoon.

Can you tell me the last code listed at the bottom? The picture is too small and dark to read the codes.

Roy

P1719.

The problems tend to occur when the car is hot and driven for awhile. Gear issues are noticeable particularly on straightaways in slow-moving traffic.

Anyone with advice?

Too me it sounds like the transmission is low on fluid, you have a you have a turbine speed sensor that is not plugged in or is bad. Can I ask if this problem happened directly after the work was done?

Here is how you check the fluid level. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Fluid was checked at least three times and changed twice. This problem has existed for over five months. This issue is a true "gremlin." I cannot get it to happen for a mechanic because it must be driven for awhile first and then shows up under mysterious conditions. Codes I have been able to read from time to time include P1719, P0700, U2107, C0561.

Those transmission and network codes can be a computer problem or an internal transmission problem. Let do a pin to pin check to make sure we are not chasing a connection problem. I see an Ignition relay that can be shorting out which would cause the problem.

https://www.2carpros.com/articles/how-to-check-wiring

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here are the engine and transmission wiring diagrams so you can see how the system works and the ignition relay location.

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Ken,

What makes you think it may be the ignition relay? Also, is that number 31 on the fuse block?

Does an intermittent problem suggest something going on inside or outside of the transmission? I am thinking something electrical because crazy things happen like ABS, brake and Stabilitrak going on and off and the gas gauge going nuts. Do you think these lead back to a faulty relay?

Big time, if the connection is weak or has high resistance (hot) to will stop powering a leg of the computer which will make the communication codes. Can you see if the PCM - IGN fuse has power with the key on? I would also check the power train relay #31 as well as #47.

I do not like cars with computers. :( I long for the good old days of uncrowded engine compartments.

Yes, those where the days when only three things can be wrong. Today many many more options. Does the PCM - IGN fuse have power with the key on?

I wanted to update this issue. I fixed the ABS/brake light/stabilitrak issue. It was a broken speed sensor - cracked in half. I managed to fish both pieces out and replace them. No more problems related to that sensor.

However, I am still having the transmission issue. Mechanic says he cannot do anything until the car goes into limp mode while he has it. I cannot force that to happen. The problem is intermittent. Logic tells me that this is more likely to be an electrical than a mechanical problem. If it was mechanical, it would likely be constant and getting worse. I can go days and hundreds of miles without this issue occurring. Then the transmission starts slipping and banging into gear again. A hard bang causes the ETC light to flash on briefly. A few hard bangs and it goes into limp mode. Let it sit twenty minutes or so and it is out of limp mode.

How do I fix this? I am afraid to go any real distance in this car. I attached a screenshot of my scanner results when it was in limp mode.

P0700 - Not a "real" code, it is a code to tell you you have a code in the transmission control system. It will pop up on the code readers that cannot talk to the rest of the system.

P1719 - Improper shift detected. This code sets if the TCM detects the conditions in the attached image. The long list on top basically says, everything in the transmission is working fine.

Then you get the flare and banging which is what is in the reasons the code sets.

You say the fluid was checked 3 and changed twice, How was it changed? Through a flush or did they remove the pan and change the filter?
The flare issue is caused by the transmission losing internal fluid pressure and the clutches slip. It could be a bad pressure solenoid or even a chunk of crud floating around in the system blocking a port. Did it start after the head gasket repair or was it going on prior to that? With 104,000 on it there is also the possibility that it is just a worn seal that is failing and a refresh is needed.

This started way before the head gasket repair. It has been going on for at least five months. It does not seem to have any particular trigger. The only thing that is always true is that it never happens when the car is cold/in the first fifteen or so minutes of driving. Sometimes I can drive one hundred miles and it does not happen at all. What do you feel would be the proper approach to diagnosing and fixing this problem? I do not want to just throw money at it by guessing.

Thanks in advance for your help!

I found some possible causes for this code. they are listed below.

All these checks can be done without the issue happening. It can be checked by the tech looking at freeze frame data stored with the code.

Roy

P1719
Descriptor
Probable Causes
1-2, Reverse Clutch
1-2, Reverse Clutch Control Valve Stuck
2nd Clutch
2nd Clutch Sprag
3-4, 4-5 Shift Solenoid Valve Assembly Stuck
3rd Gear Band
4-5 Clutch
Control Valve Body Assembly
Control Valve Body Interior Dirty
Direct Clutch
Forward Clutch
Low Clutch Sprag
Low and Reverse Clutch
Reverse Shift Solenoid Stuck
Second Clutch Control Valve Stuck
Shift Pressure Control Solenoid Stuck
Shift Pressure Relay Valve Stuck
Torque Converter Clutch (TCC) Lock-Up Pressure Control Solenoid
Transmission

Only occurring once warmed up would match up with internal seals that are starting to wear, the colder fluid and seals will work different than hot fluid.
You might try one of the trans fluid modifiers out there but I wouldn't expect a miracle.
I am afraid the final repair will be top open up the transmission and rebuild it. They are made to very tight tolerances and even wear that you cannot see will cause issues.

It is not a bad trans problem it is clearly a signal of when to and when not to shift “electronic” pull the transmission to rebuild it and the tcm will display the same symptoms with the rebuilt trans.

So you put a rebuilt in it and it still does it or am I reading your reply wrong?