Hello, my name is Mark and I will try help you with this.
Have you checked the oil level at the correct temperature.
It should take about 3.3 litres when you drain and fit a new filter.
You will need the use of a suitable scan tool to check the level properly.
I have used genuine mercedes dipstick to check but still out of the range (above the scale).Car was parked on leveled surface. Everything is related to F fault as alredy changed the automatic gearbox gear selector module bit still nothing.
Did you run all the gears through with the engine running?
And i have added the oil through the dipstick hole.
Click on the link above.
Yes and R and D gears seems to bang in to place whhen changed
Do you have a scan tool
Did you read the link I sent?
Yes carsoft 7.4 and P123F is constantly showing under EGS section but I can not find the translation of what it means
Are you able to measure the transmission oil temperature
Did you read the link I sent.
I done it on both cold and above 80C
Check the connections at the shift selector board for fault P123F
If you have too much oil in the gearbox, then you need to remove some.
Already did and pcb from selector reconditioned by ecu testing.com but still after 10min. Drive F appears on dash but usually disappear next morning.
Check the wiring plug connections for oxidisation.
Checked. Still nothing. :(
What about checking the wiring for damage, chaffes or breaks.
all wires are fine
I think you should start again.
Drain the gearbox oil and only put enough in according to the dip stick. If that means only using 2 litres then that is all you should put in.
Then raise the gearbox to operating temperature and recheck the oil level. If it requires a bit more then add it but only to the max line on the dipstick.
If the fault code still doesn't clear and you are 100% certain there is no fault with the wiring or the position sensor as you have stated then either the gearbox is faulty or the control unit is faulty.
At this point you will need specialist gauges to check the oil pressures in the gearbox under certain test conditions.