S430 W220 won't crank. Help Please

[ukcodger]

Hi guys, I made first contact with one of my neighbours this morning. He has a recently acquired and very nice 2000 S430...recently serviced and running fine until this morning.

The key inserts, the dash display works, turn the key and there's just a slightest 'clunk' from the starter.

With the headlights on, there's a very brief instant when the lights dim.....that's when the starter clunks. But then nothing, no cranking whatsoever and the lights stay full bright.

I'm going to point him to this forum but thought I'd ask on his behalf first.....Any Ideas People?

 

[grober]

Flat--ish Battery? Other possibility is a dodgy solenoid on the pre engaged starter. I don't know if that generation of S class has the 2 battery system with the main gell mat type battery in the boot-- [drives all the electronics] and a smaller conventional type at the front which is used to start the car. If its a "2 battery" car my bet is the small starter motor battery needs renewed. May detail this in the owners handbook?
I suggest you point him towards this thread- that ought to keep him usefully occupied for a few days. W220 S-CLASS ENCYCLOPEDIA - START HERE - Benzworld.org - Mercedes-Benz Discussion Forum

 

[ukcodger]

Thanks for the prompt reply Graeme...will check that out. Thanks.

 

[grober]

This is a link to a USA owners manual online http://www.mbusa.com/vcm/MB/DigitalAssets/pdfmb/ownersmanual/2000_s430_s500_s55amg_s600.pdf
These cars are extremely complex with lots of electrical "systems" Sometimes if one of these goes faulty and fails to shut down completely it can drain the battery very quickly. Perhaps your friend needs to get the fault codes read out on a proper MB Star diagnostic system to pinpoint the fault. In the longer term he may find it worthwhile investing in an intelligent trickle charger for his garage!

 

[ukcodger]

Update as follows:

RAC Homestart were called out. The service guy jump started the car with booster cables to the battery in the boot. He didn't like the look of the battery....suspect cells?
So my neighbour has been for a new Bosch 'Silver' battery and the car is presently back on his drive, waiting for another starting trial in a few hours.

So my question is....why did the old test with the headlights not yield a result. I.e. does this W220 have some sort of voltage monitor which locks out the starter if the voltage from the boot battery is too low?

 

[grober]

DESPERATE PLEASE HELP CONTROL PANEL PROBLEMS - MBWorld.org Forums
BACKGROUND
Battery drain assistance needed - MBWorld.org Forums
ONE EXAMPLE!

Hopefully the new battery will cure the problem but don't be surprised if your friends problem resurfaces in a few days. If there is a parasitic current drain this will flatten an old battery overnight, a new one might last up to a week of non-use. Sadly it's mystery problems like this that makes owners move their cars on rather than finding what can be an elusive fault. One temporary cure is to hook up the car to an intelligent charger overnight routinely but eventually the problem has to be addressed and that means using the Mercedes Star diagnostic system.

 

[ukcodger]

Thank You very much Graeme. Very informative indeed!

My neighbour's car is mobile again but I've now got a far better insight into what he, (and I suppose in time me with the CLK), might be into.

Cheers Mate.

 

[grober]

I don't want to alarm you unnecessarily. The S class and CLK have complete different levels of complexity particularly with respect to their electrical systems. So you are unlikely to suffer the same problems. Hopefully the new battery will indeed solve your friends problem- only time will tell. What it does tell you is that a battery in good condition is ESSENTIAL for the proper functioning of a modern Mercedes. I would go so far as to say replacement should be an operation scheduled into the cars routine service recommendations? If you have a complex electronic laden Mercedes model like an S class its essential that any problems are handled by technicians familiar with the complexity of systems involved. This is only likely to be available at good Independent Mercedes Specialists or MB dealerships with the appropriate diagnostic equipment and software. Hope the new battery is the end of your friends problems.