a170 cdi auto box fault please help

[wiggi28]

loss of drive to wheels will only do ten mph or so
no indication of which gear or if i am in drive on display
car is full automatic with tiptronic option can anybody help or has anybody had the same problem
thanks

[paulfran]

car has gone into emergency mode prob just showing f in the gear select box, auto box is run off its own ecu module you can have the safe mode erased but if prob is in ecu will most likely come back then may be able to reprogramme ecu or worst have to be replaced, hope this helps.

[hanif001]

Originally Posted by wiggi28

loss of drive to wheels will only do ten mph or so
no indication of which gear or if i am in drive on display
car is full automatic with tiptronic option can anybody help or has anybody had the same problem
thanks

My son has an A170 auto exhibiting the same problem. He had it diagnosed this morning. He has informed me that a device called "the gearbox selector module" is reporting a problem.

He has noticed that the 'F' failure on the dashboard is reported when the gearbox heats up during a longish motorway journey. Whilst in the "failed" state, the gearbox wont allow the selection of any of the gears via the selector. When he allows the auto gearbox to cool, the car then allows him to drive off until it heats up again. Previously, we have changed the automatic transmission fluid a few times (incfilter change), checked the pipes and flow of fluid to the auto fluid cooler radiator. Driving on non-motorway roads doesnt cause this problem. This tends to indicate the module is having some sort of temperature related failure.

He has been told that the module will cost around £260gbp + labour. Also told that the part should be reasonably easy to change.

The diagnostics is "GRM P1856-000 Internal Fault component A61 Electronic Selector lever module gear recognition module has detected an implausible lever position."