Jump Start Car = Major Problems ?
 

My car battery was weak recently and I had jump started my 1999 SLK230 several times. I thought I had fixed the problem by charging the battery , but it died again, and this time when I jumped it, the idle kept surging between 1000-1300 rpms and there was no response from the throttle. I have searched the archives and have already tried disconnecting the battery. I have also used an OBDII scanner to pull codes and didn't get any. The BAS and ASR lights are both on. I am at a loss to what may be causing this problem, but am afraid to bring it in to the dealer because I know they will just start replacing parts. Has anyone experienced this in there cars or knows of the cause and more importantly, the fix?

when you state BAS do you mean the ABS light?

If so then ,it is likely that the OVP(overvoltage protection relay) is faulty.-check the fuses on it-if blown, replace them,if the problem still persists ,then the the relay itself is faulty.

sorry, but do not know where the relay is located,maybe someone else will be able to help.:)

Thanks for the reply. However, I did mean BAS. I believe it stands for Brake Assist System. I also checked and found out that this vehicle does not have an OVP. I am at a loss to what could be causing this problem. Any other ideas? Please help. Any input from the techs would be greatly appreciated. I cannot apply gas at all, even if I floor the gas pedal. The problem still persists this morning. I also tried turning the wheel from lock to lock to reset anything, but that didn't help.

basics first
 

Have your battery tested by autozone asap... try using a known good battery in the meantime and if you can get it started get the alternator tested at autozone as well. Check your ground wires. Hopefully it is just a bad battery made worse by jumping.. wild tach fluctuations can mean the alternator is going as well.

I'm sorry, I forgot to mention that I replaced the battery with a brand new MBZ battery and the pro blem still persists. Anyone?

I am guessing on this soooo..

I speculate that the battery jump caused a voltage spike/ or current surge within the system, in todays newer computer controlled vehicles, it is similiar to a surge in the home that shuts down the home PC.

From reference material:

On most models the BAS and the ABS are integrated. On models 168 the voltage is supplied to the BAS control module ( N48) via the fuse relay box (F1). Check this fuse and relay.

On models 129,140 it is supplied via the base module ( N16/1), on models 163,170,202,208, 210 and 220 via the relay (K40). Check these for voltage, shorts,opens etc.

Hope this helps, if further clarification is needed I can dig into more reference material.

inspector1,

Thanks for the reply. Would you happen to know where this relay is located?

Thanks,
Chris

Not having much luck finding it on a schematic and I'm running out of time here at work

I'll look more tomorrow.

I can't help with the problem, but I hope folks reading the thread take note of what caused the difficulty: Boost-starting a late model computer equipped vehicle.

I owned an auto-electronics store and boosting a car meant you were instantly unemployed. No second chances. We paid out too much money to replace electronic brain devices on cars.

When jumping a car you need to turn on the headlights in BOTH cars this will absorb any Voltage spike. Steve

Thanks Steve,

So, the answer to "how to jump a Mercedes correcty" is to turn both vehicle headlights on, eh?

I'll have to remember that one. I mean, you gotta do SOMETHING if you're out there in the middle of nowhere with a bad battery.

I also have learned the hard way with jumping -- thankfully the car a Jeep GC was still under Warr. -- it was about 6 months old and I was using it to Jump another car -- I did think that this was even safer, although I do not now how I got that idea.

After that, I purchased one of those jumper batteries -- the thing is great -- we keep it in the office -- it has saved us many times over the years.

We have also used it when changing a weak batt - to keep all the memory chips powered.