722.6 Speed sensor/conductor plate

[whitenemesis]

I know but the others that I have owned, and I'm sure this was the same, if for example I was driving in D and the box was driving in 3rd at 30mph and you hit - it goes from D to 2 in the display, and drops the box to 2nd. Same situation in this car now and the D would change from D to 4 and then hit - again for the display will show 3. Only on the next - will it drop to 2nd?

Mmm, yes you're correct. Just came back in mine and clicked the downshift button and it dropped a gear and went from D to 3. Mine's an AMG but I think the modes behave the same as non-AMG when in S and C.

Perhaps yours requires a bit of recoding?

 

[m3gt2]

Next time it goes in I will get them to try recoding it but don't think I will take it in just for that, assuming it won't cau any damage?

 

[mikeeb]

My 55 AMG K when using the gearstick goes d-4-3-2-1 regardless of gear engaged

 

[bed_sat]

Thought I would update this. Had the plate, plug, filter and gasket changed. Got the kit from One Stop Gearbox Shop on ebay for £150 and the plate has Mercedes part number on so would seem genuine. It seems to have cured every problem except that manually changing down always goes D-4-3 etc regardless of which gear you are in. Would be nice to sort that but if I cant I will live with it!

Good to hear. I'll be doing mine either next Monday or Tuesday, will give another update then

I know there are some good DIY threads out there, but I thought I might give a link to this PDF on replacing the conductor plate - it's written by Febi.

It gives a list of generic codes you get from the cheaper OBDII readers that relate to the plate/solenoids/speed sensor and a pin-out of the plug and wiring diagram for the solenoids - so it's possible to check the plate/solenoids with a multimeter to aid diagnosis before opening up the 'box

http://www.autobiz.ie/techtips/febi/mercedes-automatic-transmission-conductor-plate.pdf

 

[bed_sat]

OK.......

Changed the conductor plate and shift pressure solenoid - filled up with ATF, cleared the gearbox adaptations and the original P2108 (Shift Pressure CONT Y3/6Y2) code, go down the road... and.... straight to limp mode again! :cry:

Put the solus back on, same fault code is back....

So... cleared the code again, and went into the transmission live data screen.

When displaying the currently selected gear it shows "Park", "Reverse1", "Neutral" BUT when you put it into D - it comes up with "Implausible" immediately. Getting a bit stumped.

Now wondering if it could be a fault in the valve body (stuck valve) or the TCU....

going to check the continuity of all the wires from the TCU to the Gearbox plug tomorrow or Thursday to rule out a broken wire (starting with the one for the 6y2 solenoid!) well, you never know...

Oh, and now the Radio is coming up with "cannot find audio" and won't work either! lol!

Any suggestions on possible faults appreciated!

 

[television]

If the tiptronic box the fault might be in the control ecu in the shift box, does it read normally in the display.

 

[bed_sat]

If the tiptronic box the fault might be in the control ecu in the shift box, does it read normally in the display.

It's not tiptronic - the info centre displays correctly.

 

[bed_sat]

I know what to do next....! :arrow: go up the pub! :lol:

 

[bob 6600]

Could it be a faulty selector?

 

[bed_sat]

Could it be a faulty selector?

Sorry, should have said - checked shift lever operation on the Solus. All OK.

 

[bed_sat]

Have checked the wiring at the TCU connector in passenger footwell.

All solenoids check out and the resistance values are spot on - so a wiring/plug/conductor plate or solenoid issue can be ruled out.

Next thought is the TCU.... or maybe a stuck valve in the valve body?

Would that give the error, though - it looks like a purely electrically induced error, i.e. the solenoid has failed an electrical check? Could a stuck valve cause the wrong pressure and give the same message? :???:

 

[bed_sat]

It's not tiptronic - the info centre displays correctly.

Sorry Malcolm, it has tiptronic (I was looking for paddle behind steering wheel, didn't realise it was left/right while in "D" :Oops: )

But the display shows P,R,N,D etc. as it should.

Is there any way to test the TCU without the MB kit?

 

[television]

With the tiptronic box the actual gear is displayed in the cluster.

 

[bed_sat]

I've just checked the TCU power outputs.

Think I may have found the problem..... With the ignition on the TCU is only sending 3.86v down the solenoid supply wire - it should be between 11 & 14v!

Looks like the TCU is toast. Have looked inside and can't see anything obvious, but then with the surface mount technology used I'm not *that* surprised.

Would have been nice to find a dry joint or something obvious, though!

So now will get a replacement and let you know the outcome. Fingers crossed!

 

[bed_sat]

Just changed the TCU, reset the adaptive data and things are looking good. I've moved back and forwards 11 times in the driveway and no more jolting when moving the stick into R or D.

Now I'm off to move the other cars so I can get it out and take it for a proper test-drive!

 

[bed_sat]

OK, so now no limp mode! Yaaaaay!

BUT It will only shift up to 4th...

When I first start the car, with the gearbox now in 'S' mode, I can manually shift 1-2, 2-3, 3-4. When I try to go into 5 it just displays "D" and stays in 4th.

:arrow: Anyone got any ideas????

Can't get it on the Solus 'till tomorrow, so will do a proper adaptive reset (was via accelerator pedal earlier) and code read then.

Right now, I'm off to the pub.........

 

[star]

It will only shift into top above 40mph.

 

[m3gt2]

Well I thought mine was sorted but it stalled today. Not been on star yet but with a generic reader the code P0730 is showing, apparently meaning incorrect gear ratio?

 

[bed_sat]

It will only shift into top above 40mph.

So it should shift into 5th before I'm doing 70 in 4th, then....... ! lol!!!

 

[bed_sat]

Not had a chance to get it on the Solus at all yet work has just gone bananas, so will prob. be Monday before I get the time