Oracle

My seven speed has long had a minor problem: When coasting to as stop, such as coming along a highway off-ramp, it will not downshift and even when full stop it remains in a high gear. If I try to drive it is like the clutch on a manual is slipping. No manual shifting will change the gear it is in.

Or, sometimes it will lock into 2nd gear. In either event it hasn't been an issue because the very quickest stop-start of the ignition resets things and off I go. Never fails, just a quick restart to (I guess) reboot the trans computer and set things right.

Until yesterday.

Now it is doing both of those things constantly, and not dropping into proper gears no matter what I try.

First - any ideas? Second - where is the transmission computer located so I can check my connectors?

Thanks!

Klinh

Sounded like your tranny "body Valves" is defected/stucked and not open/close to change gears. All these valve is working under fluid pressure.

Glyn M Ruck

The 722.9 TCU (electric control module) is built into the transmission & cooled by the transmission oil. You have no access.

The transmission is entering one of it's limp modes which is now not being resolved by a reboot by restarting.

You have an early 722.9 transmission. They were known for speed sensor failure which usually means a new valve body (electrohydraulic control unit). Benz will not even allow their dealers to touch the valve body. It has to be replaced as a complete unit from Germany. Benz will usually co pay for a repair because it is expensive.

Firstly.
- Has the transmission had it's regular 39K miles fluid & filter changes?
- Do you know if it has a new valve body?
- Do you know if it has the new pan & spill tube? It was redesigned.
- Do you know if it has the latest software flash?

The first step is to get this car onto a Star or Snap On Solus or similar and read the transmission codes that are being stored. That will stop a lot of guessing & then we can guide you as to what to do to resolve this problem.
Good luck

Oracle

Thanks Glyn. I am suspicious that it isn't limp mode only because limp mode should always default to the same gear (2nd I think) and now when I restart it may be in a high or a low gear.

Always had its proper service, last new fluid about 15,000 miles ago. Can't tell you if it is the latest rev because I haven't been into a dealer for about two years. It was current then but perhaps there is a new rev since then?

Don't know about the pan or upgrades.

Two codes, one is for engine. P0717 seems to apply. the other is P2006.

Glyn M Ruck

The 722.9 does not only default to 2nd in it's multiple limp modes. 722.6 did. 722.9 does many strange things with implausible signals.

Bad news, it looks like you have the dreaded speed sensor problem. You are going to have to get the car onto a genuine Star to decipher Benz specific transmission codes. There will likely be more stored that a standard OBDII reader can't read & we need to make more sense of the P2006 with regard to Benz specific codes.

There is nothing you can DIY apart from service on this transmission. I would get it to a dealer. Let them check & quote & then take it up with MBUSA. I can give you examples such as Karo's car (C350) on the W203 forum where Benz picked up the entire cost of the Electrohydraulic Unit replacement on his early 722.9.

Sorry to be the bringer of bad tidings. Let's hope for the best outcome.

P0717 = Input/Turbine Speed Sensor Circuit No Signal

P2006 = Intake Manifold Runner Control Stuck Closed

P2006 B2/5b1 (intake temperature sensor) (P0110)
P2006 check B6/1 (camshaft Hall sensor). Signal too strong. Short to positive
P2006 check B6/1 (camshaft Hall sensor). Signal too weak. Short to ground
P2006 Component N15/3(ETC control module) is faulty.
P2006 fuel pre-supply pressure sensor implausible
P2006 fuel pre-supply pressure sensor signal value too large
P2006 fuel pre-supply pressure sensor signal value too small
P2006-001 B2/5b1 (outside air temperature sensor) signal, positive/wire open cause
short [p0113]
P2006-002 B2/5b1 (outside air temperature sensor) signal, overload short [P0112]

Glyn M Ruck

See my posting here for pan & spill tube revision.

https://mbworld.org/forums/clk-class...ce-thread.html

There have been many software upgrades to the 722.9

Oracle

Yeah, and my nearest dealer is two hours away. Just kind of a hassle. I have sent their service department a note asking how best to proceed, but in all instances I am sure it involves me bending over.

And since I am not the original owner I doubt I will get any help from MBUSA, although I plan on trying. Forty years of driving these cars and they are horribly unreliable.

And my biggest concern is how can this avoided after the repair? A one year warranty won't do me any good if this comes back in three years.

Glyn M Ruck

Karo was not the first owner of his car. MBUSA know that some Electrohydraulic Units are troublesome & are sympathetic. The problem has been fixed & no longer occurs - only early units. The 722.9 is their scalable transmission going forward.

Oracle

OK ... here is the status, and I appreciate any comments.

Brought it in to the dealer. $500 diagnostic fee before a wrench touches it

The transmission problem is this: apparently there is a plate between the valve body and tranny, and it is this plate which needs to be replaced. They say MBUSA signed off that this will correct the problem, and I was direct in questioning whether there is any chance of future failure after this work. $1000.

They also found the engine tensioner is getting weak so that gets R&R $400.

Now here is the interesting one the 2006 - It seems the intake manifold is a two piece item and is coming apart. Cost to repair $1700. What in the world? Anybody know about this issue?

What the hell kind of car does Mercedes make anyway? Forty years driving these things and nothing but major problems with every one. Time for a Subaru.

Glyn M Ruck

OK that's the conductor plate & that makes sense - the speed sensors & solenoids are connected to the conductor plate. Johnand informs me that Benz USA is now allowed to replace the conductor plate only. Anything further & the above applies - complete electrohydraulic unit replacement from Germany. The conductor plate costs about $150 but there is quite a lot of labour involved in changing it.

I know nothing about intake runners coming apart. Maybe someone else can comment. Poly V belt tensioners are a common problem on all Benz engines.

Oracle

Not that I can do anything about it, but I am curious - Why would the transducer plate fail? And with low miles too.

Further, has the replacement part been modified so it too will not fail?

Glyn M Ruck

This part is in it's third generation & will hopefully now be fine. It is only early units that gave trouble as they did on the 5 speed in 2000/2001. All it is, is a glorified circuit board moulded in plastic with conductors running through it. Some German component suppliers need their butts kicked.

Thank heavens they are not talking the whole valve body. Once fitted the whole shebang needs to be SCN coded on a live link with Benz for "security reasons" with a Star DAS.

If you look at all the Indy transmission shops they are complaining that Benz will no longer sell them the conductor plate or any valve body spare parts.

This is the conductor plate.

MB_man_from_fin

I'm sorry I do not speak English, this is translated google translator.

Could you tell me how I can test my car to an automatic transmission, the hydraulic solenoids.

My car is Mb A 180 CDI model year 2005 W 169
Serial number WDD1690071J110038
Transmission. 169370 1500 0 0198416 03 722800 0 Q12

I now have it out when the transmitter electronics repair.

Can be connected directly to the car battery plus and minus 12 volt power.

Will usually these defects.

Regards
Esko
here in Finland

Paulers

Wifes car having the issue while in Orange County. I directed her to an Indy but they said MB will not sell the conductor plate or valve body to them. The indy in San Diego says they are authorized by MB and can buy the parts. Approx 1300 for a conductor plate and 1700 for valve body.

So my understanding is that the conductor can be changed without reprograming? .. but the valve body has to be programed to the car.

I checked AutohausAZ for plates but found none. How about these aftermarket conductor plates -- http://www.1aauto.com/conductor-plat...FQEcaQodbCUOCQ

Rudeney

No, it's the other way around - the conductor plate actually contains the TCU so it must be coded. FYI, I found an eBay seller who claims to repair 722.9 conductor plates. I know nothing about this, but I am very interested:

http://www.ebay.com/itm/Mercedes-7G-Tronic-722-9-Transmission-Control-Module-Conductor-Plate-Repair-Kit-/331355559445?hash=item4d26549615&vxp=mtr

Paulers

Thanks for the clarification -- My wife took it to the dealer where she was. They gave her a loaner C300 and diagnosed it as a conductor plate only (based on codes). The quote was 1200 ($300 less than my MB authorized indy) due to some first-time customer discounts. With the coding it is beyond my capability.

So I guess this conductor plate will remain a mystery to me. Car has only 60k on it but I doubt if the Trans has been serviced. I meant to do it when I got it but......

Rudeney

The valve body contains the hydraulic actuators that interact with the gears and clutch plates to actually cause the transmission to shift. The conductor plate sits between the gears and the valve body. It's the electronic interface between the TCU and the valve body. It also contains some sensors (turbine speed sensors) that give feedback to the TCU.

On the 722.6 transmission, the conductor plate was nothing but a plastic panel with some contacts in it, with a wiring harness (with the famous leaky "pilot bushing") that connected back to the TCU which was located under the passenger footwell. The 722.9 is the same setup, except the TCU was relocated and is actually inside the conductor plate. Since replacing the TCU requires SCN coding with a live, licensed copy of SDS, this is definitely not a DIY on the 722.9. In fact, I understand that dealers won't even sell a conductor plate to customers.

Oh, and as for the failure, it seems that the plastic used on the conductor plate was too soft and the turbine speed sensors would warp or "waller-out" their seats on it. This causes them to send erroneous readings, and when that is enough outside the allowable range, you get limp mode.

SamFrancis

Hi Guys


I'm new to the forum, well truth be told, I'm a fairly new Mercedes owner as well.
I recently took delivery of a 2007 CLK 63 AMG (7G Tronic W209). And if I can say so from the outset, "What an awesome car it is."


With that being said though, my troubles started a week or so ago. I had not driven or started the car for approx. 9days due to bad weather. When it did finally clear up, I took the car out for a drive. I noticed an unusual ticking sound which disappeared after the first km of driving.


I then noticed that the car was not selecting gears as per normal. It seemed as if the clutch was slipping at first but then it would only select 2nd gear. I drove it to the service center the next day and the tech guy advised me that it might be the "Electrohydraulic control unit" the code that came up was (0894- The gear is implausible or the transmission is slipping)


The quote I received was approx. R25 000.00 ($1848) to replace and configure the new unit.


My question is :
1. Is this a common fault and is this the correct diagnosis.
2. Is this a wear and tear item/component (after market warranty will only pay R4000 and their reason is that it's a wear and tear item)
3. Is there any other surprises that I should expect with this year model


Please advise

Yidney

It could well be the correct diagnosis or it may only need the conductor plate. But as for other problems, I think that engine is also prone to headbolt failure. Google or search the forums here to make sure. If so, that will make your current tranny problems seem like a treat.

SamFrancis

Thanks Yidney much appreciated.
I was told that the head bolts have been changed. Is thete anyway of telling for sure

Yidney

Lucky for you if they were changed. If you were told that, then they probably were. I think you can tell visually because I think the bolt head had a different design. You can search for that answer because you are not the first to ask the "how can I tell?" question. No need to limit the search to CLK63 discussions. This topic is very popular on the C63 forum. Anything with that engine before about 2010.

Rudeney

I agree with Yidney - sounds like a speed sensor failure, which is common (if not "certain") on early (pre-MY2009) 722.9 transmissions.

As for the other issues, the early (pre-MY2010) M156 engines suffered from head bolt and lifter failure. Both are very expensive repairs due to having to pull the camshafts and heads. That's a major ordeal on these DOHC variable valve timing engines. It's almost an engine-out job (actually easier to do if the engine is out).

SamFrancis

Thanks Rudeney.
Is there a software upgrade available for the control unit. Like in the new models, I want the throttle to be blipped on the down shift. Thought I would get it done once the repair is complete.

Rudeney

There have been several updates to the TCU code. My CLK550 was updated in 2012, which fixed the "bump" when doing a 2-1 shift by delaying it until the car was fully stopped. It actually made all shifts much smoother. Of course the AMG speed-shift transmission is different. And my SL550's transmission shifts differently - in "S" mode, it does "blip" on down shifts, where the CL did not.