7G box stuck in forth gear

[bembo449]

for the 2nd time recently the 221 got stuck in 4th gear , what I mean exactly is that it wouldn't go any further , so no 5th - 7th , tried all modes , booting it but refused point blank until I had chance to turn it off then on again and bingo ! normal service was resumed , it suggests electrical to me but could it just need fresh box oil / filter ??

 

[Cole@MBS]

I suspect the electric plate is on its way out, doing them weekly now, not cheap and has to be coded on line.........don’t delete the fault codes if you can read them!!!

 

[Taffy7hfa]

I suspect the electric plate is on its way out, doing them weekly now, not cheap and has to be coded on line.........don’t delete the fault codes if you can read them!!!

Would you say the 7 speed box is turning out to be less reliable than the old 5 speed box ?

 

[rifiki]

As above, get the codes read using Star. I had the electroplate changed a few years ago around £500.

 

[bembo449]

I suspect the electric plate is on its way out, doing them weekly now, not cheap and has to be coded on line.........don’t delete the fault codes if you can read them!!!

should my MB11 be able to get the codes for the box pal ?

 

[LostKiwi]

should my MB11 be able to get the codes for the box pal ?

I'd imagine so.

 

[bembo449]

will soon find out when I plug into it pal

 

[John Laidlaw]

Should do

 

[Mr Filipov]

Would you say the 7 speed box is turning out to be less reliable than the old 5 speed box ?

It’s not a case of would you say, it is very much known the 7 is not as reliable as the 5. The magic of tech these days. The more you put in, the higher the chance of something going wrong.

Never had a running with a 5, but both of the 7s I had had issues. The 7+ more so than the older 7. Both would hang on 6th for a period of time, before remembering number 7 exists at random points. On top the 7+ decided when it is not warmed up it will shift like a pig for the first 15 minutes on the lower range of gears 1-4.

 

[bembo449]

ive covered another couple of hundred miles of mixed driving in the 221 and its behaved impeccably , go figure

 

[bembo449]

update , gearbox got stuck again last night , plugged in this morning and got this little lot using MB11
turbine speed sensor VGS defective
no CAN received from instrument cluster
no CAN message from unit A80 ( intelligent select ) OR N15/5 selector lever module
no CAN from N22/1 AAC control unit
no CAN message received from unit N73 ( EIS )or N93 Central gateway unit
no CAN from steering column module
no CAN message received from ESP - BAS control module
Ive cleared them off and nothing has returned as yet but I expect codes will appear once it plays up again

 

[mrmb]

Looks like the electronic plate is going bad. 7G is known with this problem and it actually happens on 7G Tronic Pus is well.

 

[bembo449]

it seems very random , not done it since I cleared the codes a few days ago but on way home to day , came off a round about and it got stuck , pulled over , turned off / on , reset , all good
so what exactly are we talking about here , what is failing ?? is it a job I can repair myself ?

 

[LostKiwi]

It's the electronic speed sensor in the gearbox. As with the 5g gearbox there is an eletroplate in the gearbox which detects input and output shaft speeds and feeds them to the TCU and takes signals from the TCU and operates actuators to control the hydraulics for clutches etc.
No idea how hard it is to change on a 7g though.
MB II should show the return of a turbine fault.

 

[Botus]

just bought one for mine.... its a designed to fail part, as cole says "doing them weekly now...." (that's not unlucky its DTF ! just like it was in the 5 speed boxes)

they can repair many of the designed in issues, but not all of them !!! and at this age a £250 quid repair and £250 to fit it, just for the other bit to fail is not cost effective, buy the new part between £400 to £700 depending on where you get it and give someone £350 to fit it. They were once £1600 I believe.

mine is showing 0722 Y3/8N3 – Output speed sensor (VGS) is not available, been doing on and off for 18 months, twice stuck in first gear, used steering buttons to change up and OK after.





if you have Y3/8N4 you can't fix it. Allegedly stands for the ceramic circuit board failure

you can get any of these repaired

Y3/8N1 – Turbine speed sensor
P0717 – The signal from component Y3/8n1 (Turbine speed sensor (VGS)) is not available
P0718 – Component Y3/8n1 (Turbine speed sensor (VGS)) is defective

Y3/8N2 – Internal speed sensor
P2200 – The signal from component Y3/8n2 (Internal speed sensor (VGS)) in not available
P2201 – Component Y3/8n2 (Internal speed sensor (VGS)) is defective
P2767 – The signal from component Y3/8n2 (Internal speed sensor (VGS)) in not available
P2768 – Component Y3/8n2 (Internal speed sensor (VGS)) is defective

Y3/8N3 – Output speed sensor
P0722 – Output Speed Sensor No Signal
P0723 – Output Speed Sensor (VGS) is defective

Y3/8S1 – Transmission range sensor
P0705 – Transmission Range Sensor Circuit Malfunction
P2716 – Pressure Control Solenoid “D” Electrical

 

[bembo449]

right , I will plug in again and see which codes have returned , I expect to see the turbine speed VGS defective so I guess this will be the part I need to change ?

 

[Botus]

you have to drain out the oil, take off the sump and have it coded the car or it won't start

 

[Mr Filipov]

you have to drain out the oil, take off the sump and have it coded the car or it won't start

Still makes me laugh when Mercedes had the monopoly on the part, saying it was anti theft device. A thief will certainly go “Let me just swap out the electro plate on someone’s drive, hopefully he won’t notice me there for 2 hours whilsts I’m doing this to steal it...”

 

[Submariner1]

right , I will plug in again and see which codes have returned , I expect to see the turbine speed VGS defective so I guess this will be the part I need to change ?

Very, Sorry to hear of your woes.
How many miles had the 221 done ? ( assuming its not your C216) Or is it another dam TIME related issue.

 

[Botus]

time....mines done 55k miles