2007 S550 non-acceleration

[CocoPop]

I am experiencing what I consider to be a dangerous driving condition in my new 2007 S550. At low speeds when rolling through yield intersections or exiting an on ramp onto an interstate, there can be a significant delay in the engine response when the accelerator pedal is pressed. If an attempt is made to correct the situation by pressing the accelerator pedal further than normal, the engine does respond BUT the vehicle accelerates far too quickly. This problem is happening only intermittently - about 8 times since taking delivery of the vehicle 1,500 miles ago BUT is still a serious safety concern. Being stuck for even a few seconds (when the engine fails to respond) in an intersection or when rolling onto a main interstate from an on ramp is extremely dangerous and not a driving situation that can be anticipated by other vehicles in the traffic stream. I have already had one vehicle very close to rear ending me when I was entering a freeway yesterday. The car refused to accelerate for at least 3 seconds then took off way too fast when I pressed the accelerator beyond normal to prevent the accident. The dealership that sold me the car told me this can occur when the onboard computer is in the process of determining which gear to use. It is difficult to believe that this is the correct explanation OR that Mercedes would allow such a potentially dangerous driving condition to occur in one of their vehicles. It strikes me as FUNDAMENTAL FROM A SAFETY POINT OF VIEW, THAT THE VEHICLE MUST IMMEDIATELY MOVE FORWARD EVERY TIME THE ACCELERATOR PEDAL IS PRESSED. That the engine responds ALMOST ALL OF THE TIME the accelerator pedal is pressed is unsafe and could easily create a POTENTIALLY HAZARDOUS situation. Has any other S550 owner experienced the same problem and if so how was it resolved.

I have reported the problem to Mercedes but as yet have not received a reply.

 

[OmniCognateNeutronRangler]

Hi cocopop. The gearbox on my C240 is not exactly fantastic but I have never experienced the problem you are mentioning, nor have I seen it reported on this forum. Unfortunately most people on this site will tell you that dealing with Mercedes (certainly in the UK) is a very hit and miss affair.
Have they hooked the car up to the diagnostic software to see if any faults have been recorded?

 

[television]

We do have one member with a S320CDI who has reported the same thing.

MB told him that this is normal and that there is no problem. I can understand how dangerous this can be when the power comes on full too late. You know that the engine will not accelerate if your left foot is touching the brake pedal.

malcolm

 

[television]

Just got this out for BRP.

 

[BRP]

Just got this out for BRP.

Since we last discussed this Malcolm I have realised that this does not happen all the time similar to CocoPop. It is irritating and as it appears not to be my imagination I will try the dealer again on Monday, at least I can quote another ocurrence even if is in the USA. Previously the dealer re set all the parameters but with no effect and did not acknowledge that there was a problem.

 

[television]

I will keep my eyes open for anymore and I will PM you if some come up.

 

[BRP]

I will keep my eyes open for anymore and I will PM you if some come up.

Thank you Malcolm

 

[CocoPop]

Re foot on brake

We do have one member with a S320CDI who has reported the same thing.

MB told him that this is normal and that there is no problem. I can understand how dangerous this can be when the power comes on full too late. You know that the engine will not accelerate if your left foot is touching the brake pedal.

malcolm

:!: On a hill with foot on brake pedal holding car, engine revs increase when the accelerator pedal is pressed. Essential for a smooth take off up a steep hill - to eliminate rolling back. On a hill, at normal engine idle revs, S550 rolls backward if foot not on brake.

 

[CocoPop]

What the dealership said

Since we last discussed this Malcolm I have realised that this does not happen all the time similar to CocoPop. It is irritating and as it appears not to be my imagination I will try the dealer again on Monday, at least I can quote another ocurrence even if is in the USA. Previously the dealer re set all the parameters but with no effect and did not acknowledge that there was a problem.

This is word for word what the dealer e-mailed to me when I highlighted the problem to them:-

Quote: "Regarding your cars roll through intersection acceleration or lack of. In my experience the car will hesitate a bit when selecting the proper gear depending on speed and accelerator pedal position."

 

[BRP]

This is word for word what the dealer e-mailed to me when I highlighted the problem to them:-

Quote: "Regarding your cars roll through intersection acceleration or lack of. In my experience the car will hesitate a bit when selecting the proper gear depending on speed and accelerator pedal position."

If it is delay caused by the "thinking" time required by the gearbox, surely setting off from standstill would only require 1st gear or is a higher gear sometimes used. I did not get chance to contact the dealer so will have to wait a few weeks now

 

[CocoPop]

Software problem?

If it is delay caused by the "thinking" time required by the gearbox, surely setting off from standstill would only require 1st gear or is a higher gear sometimes used. I did not get chance to contact the dealer so will have to wait a few weeks now

With the car in C "mode" rather than S - sports mode, the engine management computer selects a higher gear for a smooth, less agressive take off. Maybe a computer software problem. Mercedes eventually replied to my email to them with a "We regret to hear of your concerns, but trust you can realize that it is virtually impossible for this office to offer a technical opinion as to whether your vehicle is performing properly or to factory specification at this distance (via E mail)."

I'm hoping they have given the dealership a hint as to what the problem is - car goes in this Thursday for a checkup.

 

[BRP]

With the car in C "mode" rather than S - sports mode, the engine management computer selects a higher gear for a smooth, less agressive take off. Maybe a computer software problem. Mercedes eventually replied to my email to them with a "We regret to hear of your concerns, but trust you can realize that it is virtually impossible for this office to offer a technical opinion as to whether your vehicle is performing properly or to factory specification at this distance (via E mail)."

I'm hoping they have given the dealership a hint as to what the problem is - car goes in this Thursday for a checkup.

It is unlikely that we are the only two customers to have complained about this. I find them a bit secretive. A similar thing happened recently when the distronic plus failed. Again no admission that a problem existed until eventually they admitted a widespread failure was the case and the part had been revised.

 

[CocoPop]

If it is delay caused by the "thinking" time required by the gearbox, surely setting off from standstill would only require 1st gear or is a higher gear sometimes used. I did not get chance to contact the dealer so will have to wait a few weeks now

The S550 went in to be checked out. I told the tech service guy that at least one other person has the same problem. He said some time back engine software was changed to eliminate this problem - occuring mainly with people who drive with both feet and do not "heel/toe".Do you use both feet? You may want to have your dealer check out the latest software upgrade for your car. What year of manufacture is your car?

On my car - engine data has been emailed to Merc. Car goes back in next Tuesday for 2nd problem solving excerise. Tech guy experienced a separate problem with the transmission durng his test drive. They may or may not be related.

 

[OmniCognateNeutronRangler]

well at least it sounds like they are taking you seriously, which is a start. The usual MB line is "it's supposed to do that" and then just walk away.

 

[television]

The S550 went in to be checked out. I told the tech service guy that at least one other person has the same problem. He said some time back engine software was changed to eliminate this problem - occuring mainly with people who drive with both feet and do not "heel/toe".Do you use both feet? You may want to have your dealer check out the latest software upgrade for your car. What year of manufacture is your car?

On my car - engine data has been emailed to Merc. Car goes back in next Tuesday for 2nd problem solving excerise. Tech guy experienced a separate problem with the transmission durng his test drive. They may or may not be related.

Thats interesting as my SL500 does not always cut when using two feet, I tried to make it do it but no way would it. It used to with quite a lag before pulling away. I will try again when I take it out.

 

[BRP]

The S550 went in to be checked out. I told the tech service guy that at least one other person has the same problem. He said some time back engine software was changed to eliminate this problem - occuring mainly with people who drive with both feet and do not "heel/toe".Do you use both feet? You may want to have your dealer check out the latest software upgrade for your car. What year of manufacture is your car?

On my car - engine data has been emailed to Merc. Car goes back in next Tuesday for 2nd problem solving excerise. Tech guy experienced a separate problem with the transmission durng his test drive. They may or may not be related.

Sorry for late reply, I am in Spain and as phone was not working (thunder storm) no internet until now. I drive using right foot for both throttle and braking. Just completed a fairly brisk 1800 mile journey and of course you get so used to the 'lag' it stops being a problem. There is a MB dealer in Estepona and I am tempted to see what the Spanish attitude to the problem is. I think my car will have had all theupdates but I will check on my return to the UK next month. My car is an October 2006 W221 S320cdi

 

[CocoPop]

Sorry for late reply, I am in Spain and as phone was not working (thunder storm) no internet until now. I drive using right foot for both throttle and braking. Just completed a fairly brisk 1800 mile journey and of course you get so used to the 'lag' it stops being a problem. There is a MB dealer in Estepona and I am tempted to see what the Spanish attitude to the problem is. I think my car will have had all theupdates but I will check on my return to the UK next month. My car is an October 2006 W221 S320cdi

Two days of inspection and testing included an engine management software update. Too early to say the problem is resolved but no instances of nonacceleration in the 1st 24 hours. Will update information on this problem in a week or so.

On a completely different topic - take a look at the new Bugatti doing 253mph!

http://www.dailymotion.com/related/2718989/video/x157l2_bugatti-veyron-at-top-speed/1