Recurring issue, appears like the battery is dead.
What is your question?
I have a 2011 S550. I know for sure it sat for weeks without use prior to buying it and had "hard starting" reported. I have a recurring "dead battery" like failure where the car won't start. Dealer has been good, but baffled. The main battery, starter, alternator, regulator, and several modules have been changed.
When the dealer gives it back with a good charge, its weeks before it has the issue, then it fails to start 3-4 times a week. Jump it, drive it, starts for a few times, then fails again.
This past time, the car was dead. Turn the key fob, no dash board, and very few clicks. When the roadside tech connected the portable jump cables, the car fired right up like there was no battery issue at all.
No one knows what to do.
Any ideas? Anyone know if the battery control module might cause this? Other component that on command to start could be shorting the battery?
Thanks.
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They replaced my ignition system. I'm told there is an obscure technical bulletin on this. They replaced the battery at the same time. So far it's been 6 weeks but I'm not ready to call it solved.
From what you are describing it may be as simple as weak battery. The S550 *REQUIRES* an AGM battery with 900+ CCA. If your battery is either old OR is a non-AGM battery, it may fall below the required CCA's to full start your car. If it's a standard lead-acid battery as it weakens (especially after sitting for a prolonged period without starting and discharges to dead/near-dead, it can not be fully recharged to the necessary CCA. It may be only able to get to ~750 CCA at full charge. AGM's can take full discharge and recharge without affecting the recharge capacity. What happens is that as the battery ages and/or the full-discharge occurs, the alternator will recharge the battery full enough to restart the engine, but over several restarts in a short period AND/OR excessive electrical usage while running AND/OR sitting parked and off for several hours (the car will use power while parked) it discharges enough that the remaining amperage is insufficient to start the car. This can be exacerbated in cold/winter weather. Not to mention you are putting considerable load on the (very expensive to replace) alternator. The kicker is that most battery shops/mechanics/analyzers will show that the battery tests "good", but that "good" is within 80% of the rated CCA of the battery, when that is technically BAD for this car's avarice electrical power consumption. If it's at 80% and sitting for a while the battery discharges below 70% or more and that remaining charge is insufficient to turn-over the engine to start it.
I've experienced this first hand and the dealer, battery shop, and other mechanics were baffled. The battery tested "good" and I spent considerable dollars having the shop attempt to track down a ghost parasitic power drain after the car was shut off. Simply replacing the battery with a new AGM battery solved the problem and never had a similar problem since. I'd recommend an INTERSTATE AGM battery to replace if you don't get the MB battery...they are better AGM's than competitors. Don't make the mistake of wasting your money on a Optima...they are 'OK' but they are more hype and marketing than a strong battery, even though they are AGM batteries. If you must go with an Optima, get a 'yellow top' but check to make sure it will fit first.
They replaced my ignition system. I'm told there is an obscure technical bulletin on this. They replaced the battery at the same time. So far it's been 6 weeks but I'm not ready to call it solved.