I just purchased my 2005 SL-600. Less than 15,000 Miles on it!
I love it but here's the problem.
When I jump on it hard from a very slow roll (did it on test drive) the car starts to take off and then nothing happens!!!

It's like someone disconnected the throttle linkage. It will accelerate but extremely slow even though my foot is all the way to the floor.
It's running,no miss or stumbling, just very very unresponsive. It doesn't matter where the gas pedal is, it just doesn't respond!

The words ESP show on the speedometer side and on the tach side shows something about "bring it to the dealer or some such thing!

The seller freaked and asked what I did. I said nothing! Look at my foot! It's on the the gas pedal and all the way on the floor!! He called his MB service rep. While he was on his cell I pulled over,shut it down and restarted it and it went back to normal. No ESP word or advice about taking it to the dealer. He handed me his cell and the service rep told me it's probably because the owner never got on it. He said "Do it again"

I did and the same thing happened again!

I shut it down,cranked it up and it was back to normal.

We drove to the dealer. The service rep took over and got on it but not as quick with the pedal as I did but the car took off and responded fine.

He assured me the owner always took great care of the car and just to ease my mind he would take it in service and check out everything on the computer.
The car checked out without any problems and he even gave me the 5 page readout.

I was in Miami and proceeded to drive home (New Orleans)

After getting some rest I was up at 05:30 and on my way again.

There was hardly anyone on the interstate so I slowed way down so that when I got on it it would down shift into first gear.

Damn! It did it again!! I did the same restart and then I thought, let me try it with the ESP off and see what happens.

The tires started to break loose and then "BAM!" It did it again!

Now I'm getting pissed because the car is out of warranty (5 yrs old)
and it's Saturday about 06:00 in the morning.

Shut it down. Same old results. Back to normal and I decide to stop and eat breakfast. On the way there, Bink! Engine Check Light pops up!

Now I'm getting a little concerned!

While drinking some coffee I remember Auto Zone has a computer!

I find one on my phone! (How did we survive without these damn Smart Phones!!) The guy says "sure" bring it over and we'll check it out.

I finish up, go outside, crank the Beast up and Walla! The check engine light was out! I'm Happy! I won't hear the wife say" Check engine light!!"
Why did you buy it? They just don't get it!

Anyway, i call Auto Zone and tell the guy what happened and thanks but I'm hitting the road.

It's now Sunday evening and I'm back home and going to go over to Hans and Fritz in the AM.

They have a great reputation and ONLY work on MB's!

What do you people think is going on?

It's only when I punch it past the resistance near the bottom of the pedal that it has this problem. And only when it shift's down to first gear,I think!

Because if I nail it at say 60mph it's no problem.

Thanks for listening!

 

You might have a turbo problem.

Did you get the Autozone read out?

 

No, Like I said in the post, I hit the road when I cranked up and the light was out.

 

Sounds like it's going into 'limp mode' when you get on it from a slow speed. The only question, is why?

Dealer should be able to troubleshoot it going into limp mode pretty easily, as that is definitely stored in the computer.

 

Let me get this straight. The car did this when you took it for a test drive before purchasing it? You proceeded to buy the car and drove it home? It keeps going into limp mode unless you go part-throttle and no down shift into 1st gear. The car doesn't have a warranty?

Are you sure the car is stock? I ask because this would seem to be a hiccup on a car that is making too much power for the transmission to properly handle. The TCU (transmission control unit) puts the car into limp mode to protect the transmission when a certain torque thresh hold is reached. This usually never happens on a stock car, but from time to time it happens when the car is making more power (i.e. ECU tune). The weird thing is that it happens over and over again. I had similar limp mode problems but never in 1st gear and it occurred very infrequently on my old tuned CL65. I know of other V12 biturbo owners who sometime go into limp mode when trying to do burnouts at the track. But as I said, those guys were not stock either.

Tom

 

We have seen several V12s that have issues with an ECU tune when they make too much power especially at part throttle! The cars will jolt/buck or go into limp mode.

The TCU does not know what to do with all of the extra Torque and HP and totally freaks out... Sometimes the car will jump into nuetral! You have to turn the car off (reboot) and restart it and everything is then back to normal...

It also might be a failing Intercooler pump...

Either way the repair costs are not to scary!

Have the dealer reflash the cars ECU to stock and see if that does it. If not check the pump...

 

+1

Re flash the ECU, as that sounds like the root cause to me.

I doubt it is the IC pump, as the OP stated that it does work from time to time. On the V-12's the heat build up on the IC's is VERY fast with a faulty pump and recovery time is dreadfully slow or non existent. Again with a bad pump.