Hello
W221 S350 Bluetec diesel. Original mileage 160k KM.
Gearbox changing late and wants do drive 3rd at 50kmh in city and 5th gear in highway 90kmh. 1-2, 2-3 are okay and smooth. Overall every gear changes quite smooth but issue is that they change late.. (changing at about 2100rpm or so)
I switch to manual and "help" changing to higher gear sometimes and then it will stay in high gear. Or just accerelate little bit harder to change at 2100-2200 rpm. No information about previous oil change. Im getting dynamic oil change with filter, updated soft, adaption resets etc done anyway, but there is one anomaly I have noticed couple times -
When fuel tank is empty (dash light is on), car drives perfectly. Good early gear changes and gearbox works like new. When I refuel, late gear changes come instantly back. Did not even turn off my car at gas station.
Anyone can explain this odd fuel level - gearbox behaviour relation?

 

The Mercedes 722.9 automatic transmission has two versions the updated 722.9 Plus gearbox will also have the A89 option code circa 2010/2011
The “Plus” model is a redesign and improvement of the original 722.9. Hardware improvements include a revised torque converter which helps longevity, cooling, and eliminating slip — an auxiliary oil pump for adequate stop/start lubrication and transmission gearset materials designed for reduced friction. As such, the Plus offers quicker and smoother shifts as the byproduct of those hardware and software upgrades.With those improvements, Mercedes determined a new fluid with different characteristics was needed. The early 722.9 model used a red fluid, more in line with traditional ATF. The Plus, however, used a blue fluid with much lower viscosity to help with the redesigned components aiming at reduced friction.

Neither fluid is compatible with the other’s transmission, so ensure you know exactly what you need before pouring any in.

if you run Blue stuff in the early boxes low speed shifts are dramatically improved - but after that all the other shifts are oddly delayed and it refuses to shift down as eagerly as it should

 

Thanks for the information. My 2012 yr W221 has 7G+ i think because I have start/stop system. Anyway, this company is professional MB gearbox specialised workshop and hopefully dynamic oil change solves problem. Ill keep updated.

 

don't forget as its a tractor the emission scandal likely impacted this car - many when updated so they have a chance at reasonable emissions behaved a bit differently post update - and quite a few owners have melt down as the car rebuilds its adaptions and holds on to gears to keep the revs up especially when its DPF regens trying to play catch up

 

Damn that makes sense about gearbox behaviour and fuel level.
In easy words, so ECU is telling car to make preparations for dpf regen and then it drives in high rpm / low gear. When fuel tank is low (light is on) then gearbox works perfectly as it should because dpf system is turned off due to low fuel..

Ive read in other thread that when DPF regen is active, ECO light is yellow? Ive been driving on highway sometimes but eco is always green. Usually I turn it off in comand every time I start driving..

 

mostly all the emission cheats meant thing don't worked the way they should...

E classes of the same era need a 7th gen DPF sensor before that even functioned - then out came the scandal and E class models (where being so much more popular the stories leak out more readily) it turns out mk1 and mk2 NOx sensors never worked (all part of the cheat) so those with adblue need mk3 NOx sensors and to flash the 3 modules with emission fix SW updates - and sly markets trying to recoup costs do the software and within 1000 mile on comes the EML and the try to get the owner to spend $1000 on the two mk3 NOx sensors they needed

Mercedes-Benz parent company, Diamler, was found guilty that they’d installed software into their diesel engines to cheat emissions testing. It allowed Mercedes to provide an inaccurate result during testing on the amount of nitrogen-oxide (NOx) emitted. This reading was in-fact higher when driven by customers on the road and wouldn’t be compliable with EU regulatory requirements.

I just read BMW, as one knew - were also cheating but they covered it up better

 

Dynamic oil change is done. Long gears unfortunately stayed.
Today I had chance to read DTC-s and this one caught my eye:
ISM - Intelligent Servo Module (Drive train CAN Bus)
Abnormal. U010087 - Communication With the engine control unit has a malfunction. The message is missing.

This module controls gearbox and maybe this is the reason why gears are long? However never had issue with putting car on D / P / R etc..
Also noticed today that after longer ride about 50km, when I stopped at the gas station for 5min and then took off, gearbox worked like new. Good low rpm shifts and everything.
Tried restarting car and boom, long gears are back . Not sure if it might be ISM or DPF issue..
I read from google that ISM issues usually are related to changing park/drive etc..
My gear selector works perfectly and not a single message or light in dash..

 

Check/clean the ISM>ECU harness connections?

 

I don't think the ISM does much aside from pushing it mechanically from PRND etc. - other madness on the gearbox electroplate getting muddled from garbage signals it thinks the engine ECU decided were a good idea makes it swap cogs (just when you didn't want it to change)

the last error - might mean the engine ECU is going bad (normal), or some fiddly fingers got at it and changed stuff - there are some hidden settings that can alter pedal feel - I wonder if someone got at them and or fitted a silly bit of junk on the pedal electronics

 

Hard to predict. I hope someone professional with Star can check where the issue is..
From my country local forum someone thought probably there is CAN issue between ECU <-> TCU that can be found only with live monitoring with Star

 

well yours says no comms... Abnormal. U010087 - Communication With the engine control unit has a malfunction. The message is missing.

many of these "speed signal" errors would be normal for a worn out electroplate

like these
P0717 The signal from component (sensor) Y3/8n1 is not available
P0718 Component (sensor) Y3/8n1 is defective
P0720 Output speed sensor circuit malfunction
P2200 The signal from component (sensor) Y3/8n2 is not available
P2201 Component (sensor) Y3/8n2 is defective
P2204 The signal from component (sensor) Y3/8n1 is not available
P2205 Component (sensor) Y3/8n1 is defective
P2767 The signal from component (sensor) Y3/8n2 is not available
P2768 Component (sensor) Y3/8n2 is defective

P0721 The transmission output speed signal is implausible, when compared to the wheel RPM signal
P0722 Output speed sensor no signal
P0723 Output speed sensor is defective
P0894 Transmission component slipping
P2206 The signal from component (sensor) Y3/8n3 is not available
P2207 The value of component Y3/8n3 is implausible
P2502 Implausible gear or transmission slipping
P2505 Gear not engaged or transmission slipping
P2550 Component (sensor) Y3/8n3 is defective
P2711 Unexpected mechanical gear disengagement

P0705 Component Y3/8s1 selection range sensor is defective
P2716 Pressure control solenoid electrical
P2783 Clutch actuator temperature too high

P2806 Component (sensor) Y3/8s1 is not learned - The TCU will have to be re-taught

solenoid issues
P0748 Pressure control solenoid “A” electrical
P0778 Pressure control solenoid “B” electrical
P0798 Pressure control solenoid “C” electrical
P2716 Pressure control solenoid “D” electrical
P2725 Pressure control solenoid “E” electrical
P2734 Pressure control solenoid “F” electrical
P2759 Torque converter lockup clutch control solenoid
P2810 Pressure control solenoid “G” electrical

 

Hello. Update. Seems like previous owner have done DPF and AdBlue off and ECU software is trash/incorrect. So I have to correctly get ECU modified and should be good.