Louie D

PO717 CODE


The 0nput speed sensor detects the primary pulley revolution speed and sends a signal to the Transmission Control Module (TCM) and Engine Control Module.


Is this correct ? I take it its the speeds sensors ? in the transmission ?

Rudeney

Yep, that's the "infamous" speed senor problem with the early 722.9 transmission. I've had that, too. I just keep resetting it in the TCU (with SDS) and driving. I've only had two incidents of "limp mode" and both reset after turning off the engine. I plan to hold out as long as I can until it fails completely.

Louie D

I kind of figured that's what it was, it has been getting worse and worse now. This is the 1st time the check engine light came on though but been in limp mode many times the last 4 months.


Is this this a dealer thing or will my Indy be able to do this ? Have you ever looked into the cost of this I am guessing about 2k with parts and labor.

Glyn M Ruck

I've just been covering this on the W211AMG forum ~ also a 2007. The turbine speed sensor output implausible is actually not a sign of a bad sensor any longer. It is a sign of a bad conductor plate. Siemens & Benz came to terrible blows over this issue of crap conductor plates. On very early transmissions the turbine chewed up it's housing.

You are heading for a new conductor plate. If you end up replacing the TCU at the same time they must flash the valve body calibration data to the new unit. Each valve body is individually flow benched & the TCU calibrated to that valve body.

Rudeney

If it's the speed sensor, you have to replace the valve body, and my understanding is only dealers can do that as it has to be coded with new firmware, downloaded from MBZ with a "live" copy of SDS. And the part itself is very expensive:

http://www.parts.com/parts/index.cfm...earch&siteid=2

Glyn M Ruck

Nah!

In the early days Benz did not trust dealers to reflash calibration data. These days they are comfortable with it. Only on very early units did the turbine chew up it's housing. 2005 & 2006 DTB's in that regard.

Glyn M Ruck

We never replace valve bodies any longer in SA. We fit new conductor plates & cross flash the calibration data.

Louie D

Thanks for the info guys will keep you updated on how things go should have this sorted out in a few days. Now to see if I can track down the conductor plate part # is this correct ? A0002702600


Thanks again

Louie D

Called dealer wants 1600-1800 + 394.00 for the part. Talked to the parts department gave me the part # 000270260088 and its a remanufactured part. Parts department said only the dealer can install this. I take it at this price they flush the tranny fluid also ?


Parts.com has it for 279.00. call to the to the Indy next see if he has the means to do this.

Glyn M Ruck

Remanufactured by who? Benz? Siemens?

Louie D

Hey Glen that's what they did not tell me but I did not asked. Just got off the phone with my Indy he said he cant touch it and I must go to the dealer..

Glyn M Ruck

I'm told that MBUSA refuses to sell conductor plates to the trade any more. I'm intrigued by this remanufactured story.

Louie D

Why does parts.com list it for sale then ? here http://www.parts.com/parts/index.cfm...earch&siteid=2


I am guessing the Reman in the part name means remanufactured I will see if I can find more info out when I see my service advisor next week.


I also did read this blog this morning. look at latest post
http://jayauto.wordpress.com/2011/06...-transmission/

Rudeney

There is a note in EPC on the valve body assembly:

Glyn M Ruck

Interesting. Never seen a reman unit offered here in SA. That is obviously reman under Benz control. Makes sense. The conductor plate is nothing but a crude circuit board sandwitched in plastic. They must have plenty of failed ones lying around that usually end up in the trash.

(after rereading. Rudeney ~ is that note for a reman valve body or reman conductor plate?)

This supply "on again," "off again" thing seems fluid.

We have never had any difficulty getting our hands on conductor plates in SA but this might be because most of the large Benz dealeships in SA are owned by Benz.

Rudeney

Glyn, for the 722.9 (at least under my VIN) I am not showing separate parts for the valve body and conductor plate as I see with the 722.6. Are you able to get a separate conductor plate for the 722.9 in your neck of the woods? Also, in SDS, when researching the repair for the "bad speed sensor" problem, it specifically states to replace the entire "hydraulic control unit" and not even try to fix the sensor.

Louie D

Just as you guys thought. I did had them reset the TCU like Rodney did and we will see how long it will last.


Kind of OT Rodney. Replaced my Battery today did what you said called Mercedes roadside they came to the office replace the battery 180.36 no install fee kind sweet watch him do it from the front window. Cant beat it.

Rudeney

Good deal on that battery. I replaced the last one myself because mine was just beginning to slow crank and I didn't want to argue with the dealer on whether or not I qualified for Roadside Assist. i paid right under $200 for mine (dealer parts counter), then they gave me a core credit of $15 or $20.

Glyn M Ruck

Rudeney,
Benz basic rule with the 722.9 has been with VGS1 version of the valve body they want replacement as a unit whereas VGS2 & newer they will allow dealers to cross flash calibration data to the new TCU & conductor plate. In SA they even repair VGS1 units now but as I say this might be because it's under direct Benz control.

On very early units they had some tolerance/clearance issues & speed sensors chewed up their housing requiring replacement. They also had the speed sensor ring issue at K1 (let me see if I can find the early bulletins.) This is in some respects the same problem. Some due to wear & some to tolerance in manufacture. Tolerance at one or other end of the range in manufacturing.

The upshot now is if we see a speed turbine sensor implausible code we replace the conductor plate & all is well on newer transmissions. i.e. the problem now relates to a poor conductor plate rather than the mechanicals that feed it data.

Yes we can get the conductor plate separate in SA as shown here.

Sorry about poor picture quality.

We have even had 722.9 conductor plates here with & sans TCU. It seems that this has settled to conductor plate including TCU so the separate units might have been experimental. I always assumed this to be a market difference. Conductor plates sold "on again" "off again" for 722.9 by MBUSA have always included the TCU it would appear)

The 722.6 conductor plate is quite a different animal as shown here:





EDIT: here is the speed sensor ring issue on early transmissions requiring a strip down.

https://mbworld.org/forums/attachmen..._27_50_59a.pdf

Rudeney

Glyn, what is the delineation from VGS1 to VGS2? Is it by serial number or part number? I'd love to be able to fix mine myself for less than $2K!

Glyn M Ruck

Rudeney, I have never found any VIN, transmission serial number or date data on when changes from VGS1 to 2 & further took place.

I'm told that this can be established with a Star. I don't have the pleasure of owning a Star to check this.

You might want to take a look with your Star. The grey area seems to be 2006/7

Rudeney

I'll do that - maybe Ill get a chance to play with it this weekend. And yes, 20006/2007 is a gray area - balance shaft issues and transmission issues abound in this time frame.

hungvnvn

My car's TCU is facing same problem with fault code 2768 and 2767. The old conductor plate intalled in my car have MB number 0335457332 (serial number 2202701806). Please can anyone kindly help me - where to buy the new part, please ?