7g Valve Block Replaced

[KeithJG]

About a year ago i was coming to a standstill to do a u turn and suddenly the gearbox went into 2nd and stayed there and would not change up,no lights on dash. Stopped, and only having the motor 2 weeks turned it off and sat for
1 minute and as being digital hoped something would reset and it did... drove home checked error codes and nothing, drove fine for a year after an ATF change.

During the year noticed gears were flaring slightly on low throttle but instant changes on full throttle, no jerks but just smooth all round driving. This was during the last year.

A few weeks back coming off the Mway on slip road and stopped at lights, pulled away and stayed in maybe 6/7th gear but slipping badly would not go anywhere, the next set of lights were just 100yds away on stopping a very bad jolt into 1st ,pulled away from standstill in 2nd gear and would not change just revving in 2nd no slipping. Stopped and turned off for 1 minute started and ok to get home a couple of bad jolts when first pulling away.

Got home and 2 error codes P2201 and P2297 motor was driving ok but flaring more but no jolts and all gears still there.

Went to Olly`s put on STAR, the print out says:

Code 2201 Component Y3/8n2 Internal Speed Sensor,VGS is defective.

Code / Event 2297 Transmission control ETC Short Circuit to Positive.

Remedial action if component Y3/8n2 Internal Speed Sensor VGS is faulty.

REMEDY:
Exchange electro-hydraulic control unit.

........

Went to Olly`s yesterday and had the unit fitted. Took about 5 days from Germany by lorry because of the nature of the part.

The electro plate is included in and is assembled on the Valve Block with every sensor or spring or whatever and TCU replaced, it is totaly new except for the alloy and TCU holder etc. Th used faulty one goes back to Germany for overhaul.

I will tell you the difference it made as i was completely surprised and still cannot understand why such a part can give the car so much more performance. Having already had a remap it feels as though it has had another because apart from the normal trends of the early 7g where 1st gear gets slightly grabbed when slowing down ,i never had this before, the box changes instantly and is in the correct gear all the time for performance or whatever no lag when suddenly going flat out it just drops a gear or two and goes like hell. Even at high speed coming back on the Mway going flat out it dropped to 6th before changing up to 7th at a good rate of knots. Before this never happened as i thought the remap had given the engine more torque to not change down but i was wrong about that one.

So overall i am over the moon with it and i believe worth every penny even me bothering twice at 5.30am to go to Olly`s, 262miles there and back.

The cost for the valve block was £947 +£189vat = £1136

Plus another £325 for ATF filter etc and labour = £1461

Luckily it did no damage to the box as the factory adaptions to allow for wear & tear were not needed. All the Software and SCN codings to Germany all included.

I want to thank everyone at PCS for there help and cups of tea.

A couple of pics. so you can see.

 

[Red C220]

When you look at the part at least you feel as though you're getting £1200 worth of stuff.

There's nothing worse than ordering something for £1200 and what turns up looks like a relay!

 

[RichM63]

My ML320 was in at Olly's earlier in the week, and I've not yet even seen it in the flesh.

But the communications and detailed advice given by the team, Graham... give rise to serious consideration about sailing back over for some more work later.

Glad that things worked out for you.
Rich

 

[zipdip]

Well you have had it done,the cost is painful ,and the problem is that many of the 7g boxes get this problem,did you look at the repair that is on offer by a some outlets,it seems they just replace the speed plate and so the box does not need to be MB programmed ,having read your post I looked on the net and it seems this way costs £500 +vat with 2 year guarantee ,I wonder how many of the independents who are recommended on this site do this repair,but anyway you car should be error free for a few years,best of luck.

 

[jpod]

Great write up and pics, thanks.

 

[Codger49]

Zipdip, I think it depends on the particular type of valve chest in your 7g box.

Earlier ones (VGS1) require replacement of the valve chest as well as the plate. VGS2 and later seem to only require the plate to be changed for most sensor failures. I also believe the VGS2 plate is deemed a 'theft relevant part' by MB and has to be coded to the car.

 

[KeithJG]

Zipdip, I think it depends on the particular type of valve chest in your 7g box.

Earlier ones (VGS1) require replacement of the valve chest as well as the plate. VGS2 and later seem to only require the plate to be changed for most sensor failures. I also believe the VGS2 plate is deemed a 'theft relevant part' by MB and has to be coded to the car.

Although cars being my entire hobby all my entire 50yrs of owning cars i am more old school but nevertheless i try to understand the later more expensive to maintain motors?
The Merc, being 9yrs old with 101,000 on the clock i expect the box is an early one but the valve block still had to be coded to the car and to Germany.
Before Olly could even order the part i had to send my ID a utility bill, the car VIN number also a photo of the identity plate on the doorshut of the car and also a photo copy of the registration document i then paid for the part as it is non returnable because it is for my car and then it could be ordered.

Well you have had it done,the cost is painful ,and the problem is that many of the 7g boxes get this problem,did you look at the repair that is on offer by a some outlets,it seems they just replace the speed plate and so the box does not need to be MB programmed ,having read your post I looked on the net and it seems this way costs £500 +vat with 2 year guarantee ,I wonder how many of the independents who are recommended on this site do this repair,but anyway you car should be error free for a few years,best of luck.

If you read my post correctly you will see that i put down what STAR said as i have the complete printout.

When first approaching Olly i told him the two error codes i had and by chance he already had an electroplate with just the two speed sensors on.

The price for this fitting and coding etc. was £703

I was booked in..... but upon the motor being put on STAR he called me out in the workshop and showed me the result what STAR was saying or recommending and that was that the error code P2201 was the failed speed sensors and the CAUSE of it was Event 2297 the Transmission Control has a short circuit to positive.

So the remedial action was to replace the whole Valve Body otherwise just replacing the electroplate the speed sensors would fail again.

It may sound strange but the cost was not painful as after doing my homework and studying and reading which model i wanted i bought the car for £2000 under price and i already knew the failings of this engine/unit etc.
It is a keeper anyway so i don`t mind especially as I have the guarantee for a couple of years.

 

[zipdip]

Well Keith I did read your posting how was I to know that fault 2297 means that you have to have the whole valve body,i am no expert,but it would seem you were going for the cheap option,if that is the right word,for a £700 repair,I simply asked had you looked at the repair option and the answer was you had and had found one but this was snatched away from you at the last moment in the workshop no less, as Olly fitted the valve body and programmed it I feel sure you will be able run the car for some years yet without a gearbox problem.

 

[DieselPete]

Can i ask did you find out what exactly failed on the valve body? As it seems an awful lot of money on something that could probably be repaired, il be looking for a c320cdi for the wife soon as our 330d is on its last legs body wise and i want to try a merc car out next but no way would i want to replace such an expensive item if i can have it repaired first. sonnax do alot of mod kits for these valve bodys and any machine shop would be able to over size the valve bores to fit a new bush ect....

 

[zipdip]

Hi DieselPete, this problem is found in the 722.9 7g boxes fitted to many different Mercedes over the last 10 years,they do not all go wrong but quiet a few do,there is some harsh words flying around between Siemens and Mercedes I suppose to apportion blame but as yet owners are on their own unless the box fails while under warranty,I would not let it put you off buying a mercedes with the box fitted when it is working well the gear changing is superb,if you like to get your hands dirty then this problem can be quiet cheap,there are about 4 or 5 codes that mean the speed plate can be repaired,you can send it away and get it repaired for about £250 with a 2 year guarantee and because it is still your speed plate you can just put it back refill the box with oil and it will not need coding by MB,or you can use a garage that offers this service,cost about £500 +vat as the poster found once the speed plate needs replacing then you are dealing with MB and it takes time and costs far more because it is a virgin part and needs coding to the car.

 

[KeithJG]

OK, so it is easy to say fit this and fit that but if you read my beginning post again you will see that i wrote what STAR actually says and recommended:

"Event 2297 Transmission control ETC Short Circuit to Positive."

This obviously means that the electrical short in the transmission computer made the speed sensors go kaput and if the electro plate with two sensors on was just replaced then the short circuit would make them blow again and at £700 inc. fitting i would still have to replace the whole thingy for another£1500`ish.

I have the whole STAR print out as STAR doesn`t just read error codes it does more than that.

I can scan the whole thing and up load if you want but it is just easier or i thought it was to just explain myself in STAR`s word`s.

Here is one thing which may help you DieselPete my motor is on 100800mls now and is 9yrs old and it states that the first error in the gearbox was at 61500 approx kilometers which is about 38200mls so they say the box can be used ok but eventually it will falter. So if those miles are the case it has travelled over 62000mls before the error codes came up in other words get it fixed.

I will add that i was wondering why i should spend out on it but when was it going to stop working?

One can drive with a headlamp off but not with the drive off!