jjsammy

Hello all..I got a 2018 GLS 450 last november...has about 4000 miles on it. Yesterday drove to a restaurant about 30 miles away from home...had great food and after that got into the car and started it and all of a sudden it wont let me change gears..i can only start and stop the car...then nothing in the center console would turn on.. you can see messages in the dash saying blind spot assist inoperable, lane assist inoperable....after leaving the car for about 15 mins..it started and let me the change the gears and we managed to get back home safely but now the engine light was on. took it to the dealership today and once they ran the diagnostics, it was showing them fault codes for loss of communication with the valve body. when they try to run a deeper diagnostic, the response is replace transmission. TheyThis is their 9 speed automatic transmission.... How can the transmission fail all of a sudden...Is there any known issues with the transmission or the valve body for the GLS?? Anybody else experienced this?

iridium18

"jjsammy" - very sorry to hear of your issue. We picked up our '18 GLS450 in October and now have 3,200 miles with no issue. Will be following this thread closely to see other Replies. Thanks for posting. Steve

Peter R.

Modern transmissions are very complex pieces of machinery gouverned by multiple sensors, control units and actors. When communication between systems is lost it can lead to aal kinds of unpleasantness.

From what you have stated it is impossible to diagnose the actual fault. Why I do however know for a fact is that there no 'replace transmission' fault code the MB diagnostic system can throw up. What is more likely is that the dealer sent the diagnostic info to the MB service and warranty department and they recommended transmission replacement. It still doesn't tell you what's actually wrong with it. MB has possibly decided replacing it under warranty is cheaper than trying to fix it under warranty.

Good luck,

Pete

jjsammy

The current scenario is they are going to start by replacing the valve body system. But then since the vehicle is this new, before the dealership does any repairs, they need some kind of approval from benz germany before they do any fixes as benz wants the faulty part sent to Germany to figure out why it failed as according to them this part should not fail for a new vehicle....a quick search did reveal similar issues that affected the earlier models with 7 speed transmission.

I love the car and Everything was running perfectly for the last 4 months and then boom this happens....just bad luck i suppose....

Since this was a major malfunction issue...should I be asking to some kind of warranty for similar thing of not happening...the reason i ask is all kinds of thoughts about lemon law and Mercedes buyback programs were running thru the back of mind....Any links where I can read more about them?

Thanks
Sam

Peter R.

While I can certainly understand the frustration when an almost new and very expensive vehicle starts throwing tantrums, I would suggest it's maybe a bit early to start thinking buyback. I don't know how many of these actuators Benz buys and installs on a yearly basis, but some are inevitably destined to fail before their predicted lifespan.
Why don't yo give MB the chance to fix it ?
The problem with the interwebs is that you only read about the problems that don't get resolved in a - what is considered by the customer - timely manner. All the people that have things going wrong with there vehicles where matters get resolved quickly never bother to post on forums. So my advice would be to hand them the keys and see if they fix it.

Remember : you can't protect yourself against statistics. Not even with a buyback.

Pete

jjsammy

Update: Got my vehicle back on last friday after the dealership replaced the valve body. Went on road trip - texas to oklahoma - approx 1000 miles...no issues at all...the car was gliding on the highways...one of my most comfortable road trips.... Came back home parked my car in the driveway late sunday night, turned off the engine...unloaded my bags...went to start the car and pull into the garage...i started getting the same messages again....blind spot assist inoperable, lane assist inoperable...and engine light comes on......Thank god that this happened right after we reached home...took it to the dealership to have it looked at again.....the service person after talking to somebody (possibly some engineer at mercedes ) said that they also had one other instance of similar messages and symptoms and it had to do something with some connection between the ignition and valve body system. Lets see what they find this time....

This was the notes from the tech from the last repair visit :
4487 VALVE BODY INTERNAL FAULT CONNECTED BATTERY CHARGER RAN SHORT TEST FOUND CODE P060C00 INTERNAL FAULT WITH VALVE BODY RESULT REPLACE VALVE BODY LIFTED VEHICLE DRAIN FLUID REMOVED TRANSMISSION PAN REMOVED AND REPALCED VALVE BODY INSTALLED IN REVERSE ORDER AND FILLED TRANSMISSION FLUID PERFORMED INITIAL START UP TEST DROVE VEHICLE AFTER REPAIRS MILES OUT 4487 MILES IN 4490 FOUND TO OPERATE AS DEIGN AFTER PERFORMING FOUND ALL CODES TO MOVE TO SOFT STORED

jjsammy

Got another update...Turns out there was also a faulty steering column module that was sending false signals saying that Valve body had issues. Also loose connection in the wiring under passenger front seat that was causing the center console to power off whenever the spot assist inoperable, lane assist inoperable messages use to come up. Once these two things were replaced...everything is working the way its suppose to be. The shop guys had nice on the job training with this issue cos they had not seen this one on the new GLS at all before...Just wanted to share just incase anybody else gets the same issue....

iridium18

jjsammy - Thanks very much for the follow-up post. As an '18 GLS450 owner, I appreciate hearing the issues as well as the actual solutions. So thanks again for the update. Steve

AJNV

Hello folks,

To add more on the 2018 GLS450 transmission, I own the same SUV and now have ~3200 miles on it. Following are my observations;
- Inconsistent harsh shifting from D4 - D3- D2. I am unable to tell what triggers that, but some times, I feel a thud in my brake pedal as I am slowing the car to a stop and the tranny goes from D4 - 3 - 2 and stops.
- Some times (I'm still looking at what occasion and terrain causes this) the transmission shifts to D1 and its even more rough getting into D1 and getting out of D1 to D2 or higher gears. I almost feel a push up as if its a sticky clutch.
- Once again does this occasionally. When its running smooth, its runs great. Have also observed that, in long stop & go traffic, this behavior kicks in and automatically goes away
- I have power fold second row seats, the larger seat (60/40 split) seat belt socket gets stuck with the smaller seat (40 split) and completely bends it to a point and then it stops. It took me some time to figure why were these seats not folding all the way down and get stuck when the floor was absolutely clear and found this one out.

Has anybody had these problems with the new car? I'm actually stunned that Merc did not pay attention to the details like power folding seats and least to say the spring loaded head rests (lots of thread already on older models as well)

syedabrar

Were you able to diagnose the issue with of inconsistent harsh shifting from D4-D3-D2 ?

chassis

For future reference, this transmission is the 9G-Tronic in a 2018 X166 GLS 450 with M276 3.0L V6 twin turbo engine.

mike10872

same issue here with 2018 GLS 450 w/83k miles. any update?

dro45

Try resetting the adaptive transmission.

Reset procedure worked! Here it is for anyone else having similar problem.
During this procedure, do not touch anything in the car. Don't fiddle with the radio, etc. Do nothing but the steps below. The exact order and timing are important.

Also, if keyless go, remove the button and use the key.

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 30 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 OFF position.
7. Start the car and drive for 15 minutes.
   
   

chassis

This is the same urban legend floating around the internet for nearly 20 years, associated with nearly every vehicle brand. It doesn't do anything. There is no transmission reset.

dro45

No disrespect here. But, urban legend or not, I was having stuttering shifts D2-D3-D4 and was about to have to go to the dealer. Someone gave me this procedure and I did it exactly as I typed.
My transmission immediately began shifting perfectly.
And that's the truth.

dro45

https://www.mercedesmedic.com/reset-...-instructions/

dro45

https://www.mercedesmedic.com/reset-...-instructions/

ssbreddy

Were you able to get the solution for the power folding split seat? I have something similar problem, when I press the easy entry button on the driver side second row seat it tries to fold but never folds. I can see the leaver getting activated and the front seats moving a little away but nothing happens. The seat does not fold. But the other side seat the smaller (40%) one folds perfectly.