Chris1979

Hey guys, if you change the torque converter lock up solenoid do you need to program anything? I'm going to do a trans oil change with torque converter flush but while I'm already there was wondering about that. Symptoms are idle unsteady under slight acceleration while maintaining speed.

Plutoe

get a scan biff before you put your finger in the air expecting answers changing anything because you think so
if it was me i would change the trunk liner as the root cause

John CC

I'm sorry, but does that make any sense to anyone? Seems like idling, accelerating and maintaining speed would be three mutually exclusive conditions.

Odd Piggy

You’re have to reread your post and clarify it for people who aren’t seeing it happen.

Have you actually changed the TC lockup solenoid or are you asking because you’re planning to?

How many miles are on the vehicle?

When was the last transmission service?

Plutoe’s reply is sarcastic, but on point.

John CC is a serious member trying to help, but none of us can interpret that symptom description.

Chris1979

Alright guys.

2011 GLK350 115K MILES. I BOUGHT AT 110K. DON'T KNOW MAINTENANCE HISTORY ON VEHICLE. I HAVE NO RECORDS AT ALL. TRANSMISSION SHIFTS FINE WITH THE EVERY NOW AND THEN A SMALL SLIP. HOWEVER WHEN I MEAN UNSTEADY IDLE UNDER SLIGHT ACCELERATION I MEAN KEEPING WITH TRAFFIC AROUND LETS SAY 20-35 MPH. THE IDLE JUMPS UP AND DOWN A BIT FEELING LIKE A HESITATION. I HAVE READ QUITE A BIT ABOUT THIS AND SEEMS TO BE COMING FROM THE TORQUE CONVERTER CLUTCH LOCK UP SOLENOID. I WILL BE DOING A TRANSMISSION FLUID CHANGE WITH A CONVERTER FLUSH. THE QUESTION IS NOT WHETHER I SHOULD, WHY, OR WHAT. THE QUESTION IS IF IT REQUIRES PROGRAMMING OR IF YOU GUYS KNOW OF ANYTHING LIKE THAT. I DO ALL THE WORK MYSELF AS IT IS NOT ROCKET SCIENCE, JUST DON'T KNOW IF IT REQUIRES PROGRAMMING SINCE I HAVEN'T READ ANYTHING THAT SAYS IT NEEDS IT. JUST MAKING SURE!!!!

Odd Piggy

Okay. New to you with no service history. Not performing smoothly under certain conditions.

My GLK350 transmission went 155,000 miles trouble free, but it was maintained regularly. This one probably wasn’t.

Another MB site says that after replacing the torque converter solenoid an “adaptation” should be performed. It doesn’t give details other than it’s to coordinate the ECM and TCU for the characteristics of the new solenoid/clutch pair. It’s dealer “level” according to that site. I suspect there are shops that have access to the process with high end programming tools (Xentry maybe?).

A 3rd general automotive site with a Mercedes section says that it’s a 3 step process that requires monitoring the vehicle performance while driving or on a dyno. It also says that given enough time, the adaptation will be done automatically if the transmission sees enough varied conditions.

Do you have a scanner that can check for transmission codes? It might be good to know if it’s that solenoid causing the driving issue.

Chris1979

Thank you buddy, all I know it's that it was sold as a used vehicle in a MB dealer when it had around 60k miles. However when I bought it looked like last owner drove it and pretty much just did that. I mean the spark plugs were the original ones LOL. I had also read about what you were saying and also read that just to reset the TCM and drive it. My friend has the Autel scanner and we checked for codes all over and there are no codes present or saved. So there's that. I'm going to order the TCC as I already have everything else. Thank you for your response I really appreciated and I'll be on the lookout to see about what you talked about!!

John CC

What we have here is a failure to communicate. The only way to idle at 35 mph is to throw the trans into neutral, at which point it's hard to accelerate.

Are you trying to say that when trying to hold a steady speed between 20 and 35 mph the engine surges?

Adaptation is the process of the transmission control unit evaluating shifts and making adjustments to the way it applies and releases clutches, bands, etc. You can force it to relearn the adaptations, and probably should if you're changing hardware.

Transmission adaptive learn reset procedure:

1. Turn the key to position II (run). Do not start the engine.
2. Press the throttle to the floor. Activate the kickdown switch.
3. Keep the gas pedal pressed for at least 10 seconds. Hold to step 5.
4. Turn key to OFF, position 0. Do not remove the key.
5. Release the gas pedal.
6. Wait 2 minutes. During this process, key is left in the ignition in the 0FF position.
7. Start the car and drive for 15 minutes.

Odd Piggy

I’m interpreting 1979’s idle in his posts as RPMs.
Thanks for the TCM reset procedure.

Odd Piggy

Original spark plugs is a clue to how it wasn’t maintained. No tranny codes, so you’re probably gonna be okay.
I would just go ahead with the fluid and solenoid. Then do the reset to tell the TCM to relearn. Since there is one new solenoid in the system it needs to see how you drive normally. If I remember correctly, it has 3 things to learn with solenoid fill time being the mist important. So don’t take it extra easy or push it really hard.
When you get them right, these X204s are really satisfying vehicles.

Odd Piggy

Forgot to mention this: (maybe you already know)
A 2011 GLK should have a 722.9 7G-Tronic Plus transmission that requires spec 236.15 transmission fluid that is blue.
You can double check your transmission type by entering your VIN into https://www.lastvin.com, calling a dealer and giving the VIN, or buying your fluid from a store that verifies by VIN like FCP Euro or Pelican parts.

Chris1979

Thank you!! Yes I decoded the vin a while back. It does use as you say the blue fluid. I have already bought everything from FCP euro just holding off since I'm going to take off the pan might as well change the solenoid while I'm there. My trans has the option A89 friction reducer i believe is called as well. Thank you guys.

Chris1979

Thank you John, i really appreciated for all the info. I had heard about this procedure, haven't done it yet. However I will and thank you again for the info. These forums are a wealth of knowledge.

Chris1979

Here is a picture of my 2011 GLK350 FOR YOU GUYS. HAVE A GREAT WEEKEND