C55 Auto jumps in Manual from C

[Power_n_Glory]

Hi all

Just picked up my 'new' C55 AMG Estate from a local car dealer. Had a short test drive, basic RAC inspection, MOT etc.

Love it - fantastic motor!

BUT, when I have been driving around for a while, then take off from a standstill smartish, the gearbox goen spontaneously into Manual mode, showing 1 on the dash. I definitely did not press buttons or touch the selector shift.

I have seen threads that say it can stay in 1 from a Sport mode take off but this is from C and has happened a few times.

Is this normal? Really?

Before I take it back and get the 'they all do that sir...' I'd like to have some confidence in responding.

Basic stats; 04 car, genuine fMBsh (checked with original dealer - suggestion from another thread ), no ATF change yet, 65k miles.

Have others had this?

Cheers!

Mike

 

[ddavidm]

Well mine's never done it so don't be fobbed off with the reply you've alluded to.

 

[whitenemesis]

If you accelerate hard from stand still in C mode the box will drop into 1st gear. Certainly did on a CLK I test drove recently and does on my oil burner as well. The mode indicator still shows C in the cluster display though, or at least it does once the shifts up

 

[Power_n_Glory]

Thanks for the responses. Dealer agreeing there is a problem, also agreeing it's probably with the transmission control unit, so off to their gearbox speacialist next week for work. Hopefully they can do an ATF change at the same time...

 

[brucemillar]

Thanks for the responses. Dealer agreeing there is a problem, also agreeing it's probably with the transmission control unit, so off to their gearbox speacialist next week for work. Hopefully they can do an ATF change at the same time...

I have a C55 estate and can confirm that it does not behave like yours.

Good luck with the fix. Let us know how it goes.

 

[Charles Morgan]

Neither does my C55.

Good luck!

 

[AlanD]

Yeah, I'll concur ... mine does lots of things .. but it don't dooo that! ;o)

 

[Power_n_Glory]

Ok, took the car to the dealer's Mercedes Specialist - Hampshire Service Centre - where it was plugged into the diagnotics... no fault codes. But the chap recognised the fault and said it was a known problem, usually caused by oil seeping into the control unit, requiring its replacement. Not in this case...

The chap looked into the transmission control unit with the computer and found that the VIN had not been set on the unit - it was full of zero's which suggested that the unit had been replaced at some point but had not been associated with the car. So that was put in.

Also that the wheel mounted buttons had not been linked to the gear selector int he software, which was the probably cause of the random jump but had meant that I could use the wheel buttons in D mode! Which I quite liked to pop down a couple of cogs for a cheeky overtake whilst in D - ho hum!

Well, they now are linked and the box had learn mode reset. Off I go with the dealer graciously picking up the tab.

Was impressed by the specialist - seemed a good guy who knew what he was doing. He said that the ATF has been changed and pointed out the weak areas of the car when asked, which was entirely consistent with postings here!

I haven't had the 'random into first' thing happen since but I do miss the always-live wheel buttons. I suppose I can always have them unlinked again. But it now seems to be how MB intended it.

Thanks to all!

Mike

 

[Lenny63]

That's great news you got sorted.

There is no better feeling than an easy fix, especially with the confidence that the specialist seemed to know exactly what he was doing etc.

How are you finding the car?

I certainly am toying with one of these in saloon format circas 1.5years away - it's quite exciting to hear that they seem to be predominently bullet proof...however the usual weak areas that he wanted out and you refer to? Care to give us a run down?

Lenny

 

[Alps]

good result, at least you spotted it and the dealer sorted the cost out, good luck with the car!

 

[Power_n_Glory]

Lenny

The things he mentioned were;

Rust in the wheel arches - just because the wider tyres can mean stone chips in the paint on the top and front inside the arch and if not checked can get a hold. Mine has been Hammerited!
Likewise in the estate boot lid beneath the number plate plastic trim because it is a water-trap, bit of a pain to get to but ultimately easy
Springs and bushes in the suspension can wear - mine has new rear springs and short trailing arms including bushes but all else it tight and squeak-free
Brakes can wear as the car is fast and the brakes are excellent! Discs, particularly fronts, are a little pricey
Tyres, as above, although I found them not too pricey at about £130 a corner
As part of the servicing schedule, make sure all the filters are changed, the
transmission fluids are changed at about 50k miles and the spark plugs at each 50k. Coolant and brake fluids too. Cleaning/relaxing the AFM seems to be recommended after a few miles.

I might have missed stuff but that is the list I have gleaned from here and talking to people. The mechanicals are the simplest I could find in this kind of elegant performance car and although there are never any guarantees (no, really!) seemed to me to give a great promise of of toughness, performance and hard to come by style. I get between 24 and 26mpg on a long run (dash showed up to 28.3mpg at one point average over 50mph over a few hours) down to 17 when I push on. Not bad, I reckon.

Not cheap to run but a blast...

 

[BTB 500]

Sounds good, can't really justify changing our old A4 Avant at the moment but if we ever do I reckon a C55 Estate would do very nicely!

 

[ddavidm]

A blast indeed. A few months into mine now, and absolutely loving it.

Economy....28.3? pfft. I raise you..recently got 33.7mpg over 53 miles in 1 hour. For a 5.5l V8, I think that's pretty impressive really.

 

[Lenny63]

Lenny

The things he mentioned were;

Rust in the wheel arches - just because the wider tyres can mean stone chips in the paint on the top and front inside the arch and if not checked can get a hold. Mine has been Hammerited!
Likewise in the estate boot lid beneath the number plate plastic trim because it is a water-trap, bit of a pain to get to but ultimately easy
Springs and bushes in the suspension can wear - mine has new rear springs and short trailing arms including bushes but all else it tight and squeak-free
Brakes can wear as the car is fast and the brakes are excellent! Discs, particularly fronts, are a little pricey
Tyres, as above, although I found them not too pricey at about £130 a corner
As part of the servicing schedule, make sure all the filters are changed, the
transmission fluids are changed at about 50k miles and the spark plugs at each 50k. Coolant and brake fluids too. Cleaning/relaxing the AFM seems to be recommended after a few miles.

I might have missed stuff but that is the list I have gleaned from here and talking to people. The mechanicals are the simplest I could find in this kind of elegant performance car and although there are never any guarantees (no, really!) seemed to me to give a great promise of of toughness, performance and hard to come by style. I get between 24 and 26mpg on a long run (dash showed up to 28.3mpg at one point average over 50mph over a few hours) down to 17 when I push on. Not bad, I reckon.

Not cheap to run but a blast...

thanks very much - very informative

my main routes in and out of work are dual carriageway and motorway so I certainly could live with 24-26mpg

Is the power on tap simply bliss ?? how do you find the auto set up? do you find yourself in tiptronic mode a lot??

are the bushes/suspension set up mostly the same as the std saloon cars ? thinking of crazy AMG specific prices here....

 

[Lenny63]

A blast indeed. A few months into mine now, and absolutely loving it.

Economy....28.3? pfft. I raise you..recently got 33.7mpg over 53 miles in 1 hour. For a 5.5l V8, I think that's pretty impressive really.

Impressive indeed !!!

 

[ddavidm]

thanks very much - very informative

my main routes in and out of work are dual carriageway and motorway so I certainly could live with 24-26mpg

Is the power on tap simply bliss ?? how do you find the auto set up? do you find yourself in tiptronic mode a lot??

are the bushes/suspension set up mostly the same as the std saloon cars ? thinking of crazy AMG specific prices here....

Power on tap bliss? Yes, combined with the sublime soundtack of that burbling V8 (if you get the exhaust tinkered with...the std exhaust note is too muffled for my taste).

The one weakness of the car IMHO is the auto box. In M mode, the gear change is pretty slow to react to your input. In full auto mode though, it's fine, and S mode livens things up by hanging onto the power longer and seems to react to kick downs more quickly.

Not sure if the suspension components are shared with std W203's I'm afraid. I suspect some are.

If your commute is dual carriageway / motorway, the C55 is the perfect choice. Refined, comfortable, decent mpg, and the ability to lose your licence in 5 seconds should you so chose.

 

[Lenny63]

If your commute is dual carriageway / motorway, the C55 is the perfect choice. Refined, comfortable, decent mpg, and the ability to lose your licence in 5 seconds should you so chose.

:bannana: Point duely noted about std exhaust......secondary cat & resonator delete seem to be the way to go

 

[Lenny63]

If your commute is dual carriageway / motorway, the C55 is the perfect choice. Refined, comfortable, decent mpg, and the ability to lose your licence in 5 seconds should you so chose.

:bannana: Point duely noted about std exhaust......secondary cat & resonator delete seem to be the way to go

 

[Power_n_Glory]

I do have to agree with ddavidm that the auto is the (only) weak point - my mind has even started to wander and I find myself fantasizing about a manual conversion and I've only had it a month!!! It does handle really well but the slush box means that confident balance-point throttle work on fast corners is more unpredictable than it needs to be. Might post a question to see if anyone has done one...

I wonder if my exhaust might have already been tinkered with, as it's definitely present and audible at motorway speeds from the rear and opening it up with the windows down is like sticking your ear to the doors of Valhallah! I am told by my son, who I have overtaken with the thing floored, that the noise is incredible on the outside - much more than the inside.

Question - how do I spot the resonator being deleted? Presumably it's tucked up in the exhaust somewhere near the front?

 

[ddavidm]

Have a look under to see if the secondary (rear) cats have been taken off.