HypnoE63

I have a 2007 E63 and have had no issues since I bought it in early May (has 34,200 miles on it and no accidents). I have continued to get an ESP malfunction and a check engine light after several trips to the shop in which they have replaced the serpentine belt (it broke due to a pulley freezing up) and when it happened a second time a day later, they replaced another pulley along with the another Serpentine Belt (apparently there were 2 pulleys messed up). After all this I am STILL getting this ESP malfunction and my engine revs up from 800 to 2000 on its own!! It just sits there and revs up and down. I am lost. My voltage gauge is going crazy (between 12.8 and 14.2 Volts) and I could swear that when it ran normally it was ALWAYS at 14.1. I never saw it fluctuate before. Can any other owners verify this. I have to take my car in for the 3rd time in a week and am at my wits end here. Any thoughts are greatly appreciated!! Thanks...

sunil517

If so check Volt at the terminal. my 07 OEM battery is 14.1 on the guage.
The ESP came on once when I did a hard 0 - 140 pull once. I wash the calipers and pads real good and never had the problem since.
I can not see how the belt can cause the ESP. I can see the belt being a problem for volts but not ESP.
I am going install a new battery just before winter to be on the safe side. 5+ yrs is good battery life.