7G Gear Box Limp Home Mode.

[Treborsweet]

Hi Mike, no i'm not avoiding them, Google is very powerful & i like to look around at problems.
i did phone one and they was talking around £200 just for diagnosis.

I now know it the conductor plate (£220) to repair (£115 for 722.9 gearbox service kit, oil, filter bolts etc) & around £200 labour for my mechanic who really seems to know his stuff so £535 all in i think is very good.

 

[ilunn]

after rebuild the correct trans-mission fluid level requires a diagnostic unit that will tell you the transmission oil temperate and a dip stick, If i was you do bit of research on changing the fluid for your specific transmission, get clued up and chat to the guy you are getting to do the job If he does not have the dipstick or diagnostic unit capable of reading transmission oil temp (some cheaper units don't I purchased a £200 unit just to do my refill) or tries to say the procedure is not necessary take it some where who knows how to do it. Is not just refill with same amount that came out. Also pack the conductor plate very very well and get insurance on the postage to cover cost of new unit should it get damaged or lost.

 

[Treborsweet]

Does the 722.9 need a dip stick?

 

[ilunn]

Does the 722.9 need a dip stick?

looks like your gearbox differs from mine and does not use dipstick. Just found this that might help.

DIY 722.9 7G-tronic 7-speed automatic transmission service thread - MBWorld.org Forums

 

[MikeInWimbledon]

Hi Mike, no i'm not avoiding them, Google is very powerful & i like to look around at problems.
i did phone one and they was talking around £200 just for diagnosis.

I now know it the conductor plate (£220) to repair (£115 for 722.9 gearbox service kit, oil, filter bolts etc) & around £200 labour for my mechanic who really seems to know his stuff so £535 all in i think is very good.

Good luck with all that. I made my comment because you were still driving around and being surprised that the car was going into limp mode. I wasn't suggesting asking MB for a £200 diagnostic, I was suggesting a conversation with an MB Specialist - I was meaning a free conversation with an MB specialist who might help you with scoping it all out.

Just over £500 seems good value to fix the problem, check over the gearbox and do a gearbox service.

 

[Treborsweet]

Hi Mike , the car has been parked up and should be going in today or tomorrow to start the process, hopefully done by next weekend.
Its certainly the speed sensor in the conductor plate, spoke to ECU Testing and they do alot of these with the error codes i have.
I'm having the gearbox oil and filter changed and torque converter drained, ECUTesting give a lifetime-unlimited mileage warranty on the work as well so hopefully i'll have no more promblems with the gearbox.

I will keep the post updated.

Cheers.

 

[leef44]

That's limp mode "jerking" into action again. If you don't want to talk to skilled MB mechanics about the problem, you'll find the same explanation in various places on Google. But with a decent car like a W204, why not talk to people who spend their time working on these cars?

Agreed, you would be better off going to Olly at PCS Horndean for a proper diagnostic and resolution. Sometimes a fault code appears as a consequence of another fault. You don't want to be replacing parts which are not broken.

 

[C43AMG]

My S-Class is with Olly at the moment with the exact same problem. Put it on there Star machine and found the problem and have ordered the parts which have to come from Germany. Olly did say what exactly was wrong, me being totally ignorant, just told him to go ahead

 

[KeithJG]

I would tread carefully with a repair as MB don`t supply the parts to others anymore it has to be done through them but not by the main dealer.

You will not know if the speed sensor has caused the problem until you have the correct error code via STAR.

I used PCS at Horndean and my error codes were for the speed sensor but also for the TCU as it was shorting out inside and causing the sensors to blow.

So if you just have then repaired they could blow again and another £500 needed?....it is not as straightforward as just replacing speed sensors.

I had the same symptoms as yourself a restart cured it until the next time it happened.

I had the TCU and a full conductor plate with electro-hydraulic valves fitted which came with a 2 year guarantee. To fit you have to use a place with STAR online otherwise no contact to Germany for any recoding a new to the car parts.

I had a full print out of the TCU faults by STAR and the problem started at 65,000mls but i didn`t buy the car until 96.000 so it had this problem rearing it`s head when it wanted to for all those miles.
I simply could`nt drive a car that was going to get stuck in gear or whatever when it wanted too.

 

[chrisk2010]

Agree with KeithJG on this one.
I just had the same problem with mine and took it to Autoclass in MK they had to change the plate and sensors (electrics kit) and code the new stuff to the car 2 years guarantee also.

This part has nothing to do with Autoclass but i was also told the oil was low, the dealers i brought it off collected it it within warranty and returned it stating they had replaced the oil and the low oil was the problem. To cut a long story short a week...ish later the fault caame back and i immediatly booked it in with Autoclass. Within 20 minutes they diagnosed it with Star finding it was indeed the conductor plate and sensors throwing up other fault codes.

3 hours later car runs like new

 

[zipdip]

Well I hope all goes well,when you have a 7g box playing up you must get it on a star,it is vital that the problem is identified,it is then that you can decide how to repair it,I suppose it depends on what you want to pay ,I suppose most will say as little as possible,you can get the plate removed and sent away to a number of companies who will repair it and when fitted back in the car it will not need star to code it to the car ,as in a earlier post the cost is very reasonable,if I had to do it I would use a indy,it looks like the whole job is around £600,a few years ago it was over a £1000

 

[Treborsweet]

Does it have to be a Star machine or any good error code scanner?

 

[leef44]

I'm no expert but following from this thread and other threads, I would say yes it has to be STAR. For example, there are past threads (sorry, haven't got the energy to search for any right now) where there are people who've taken their cars to their trusted local experienced garage and then they've been told to get it on a STAR diagnostics. The poster then asked for help on this forum for nearest STAR specialist in their area.
However, it is best to take it to a MB specialist who has STAR. Their were a lot of fault codes on STAR that came up when I had my whole dashboard flashing up so I thought a lot of things needed replacing, but Olly at PCS Horndean was able to work out that it was only the speed sensor that needed replacing, then all was fixed.

 

[Treborsweet]

I'm no expert but following from this thread and other threads, I would say yes it has to be STAR. For example, there are past threads (sorry, haven't got the energy to search for any right now) where there are people who've taken their cars to their trusted local experienced garage and then they've been told to get it on a STAR diagnostics. The poster then asked for help on this forum for nearest STAR specialist in their area.
However, it is best to take it to a MB specialist who has STAR. Their were a lot of fault codes on STAR that came up when I had my whole dashboard flashing up so I thought a lot of things needed replacing, but Olly at PCS Horndean was able to work out that it was only the speed sensor that needed replacing, then all was fixed.

Hi which speed sensor did you have changed (Y3/8N2) by any chance?

 

[Treborsweet]

Had mine all done yesterday, speed sensor replaced.
codes cleared and it drove perfect for around 30-40 mins then p0705 error code reared its head AARRGGHH, going back to garage this morning.

Any ideads anyone??

 

[MikeInWimbledon]

Had mine all done yesterday, speed sensor replaced.
codes cleared and it drove perfect for around 30-40 mins then p0705 error code reared its head AARRGGHH, going back to garage this morning.nnAny ideas anyone??

With a decent car like a W204, why not talk to people who spend their time working on these cars? You can talk to the Service Advisors on the Front desks for free, and a diagnostic test at AMC or PCS Horndean won't cost you much - less than £50 typically, although ask them first. They're MB trained and deal with this stuff all the time.

I understand the desire to use non-specialist garages to change oil, but this is a long way from "any fool can do this" territory.

 

[chrisk2010]

I don't know if i'm helping but on mine they replaced the turbine and internal speed sensor plus conductor plate the parts had to be coded to the car so needed the log book.

You do need the Star though i done a fair bit of reading on code readers and to some up most will only read the engine codes NOT the transmission codes.

Because my fault threw up engine faults as well if i would have brought a £150 reader from Amazon i still wouldn't have got anywhere near the problem.

 

[BlackC55]

We can buy the parts now. They call them "theft relevent parts". As long as we have the paperwork for the identity of the owner etc.

 

[Treborsweet]

Hi all finally had conductor plate replaced & reprogrammed to the car but i have noticed i am missing M (Manual) mode, i only have E (Eco) & S (Sport) modes.
Car is booked to go back to the garage to diagnose, also when driving in E or S and you manually change gear from the paddles it shows the gear number but when you press back to E the gears chamge automatically but the gear number stays on the dash display instead of showing E or S.
I am guess this is a coding issue, can anyone shed any light?

 

[Treborsweet]

Hi all finally had conductor plate replaced & reprogrammed to the car but i have noticed i am missing M (Manual) mode, i only have E (Eco) & S (Sport) modes.
Car is booked to go back to the garage to diagnose, also when driving in E or S and you manually change gear from the paddles it shows the gear number but when you press back to E the gears chamge automatically but the gear number stays on the dash display instead of showing E or S.
I am guess this is a coding issue, can anyone shed any light?

Bump.