Break pads should be checked if not replaced. Check condition of rotors at the same time.
The service indicator light, in your Mercedes ML 270, can be reset by holding in the engine oil life button. The engine oil life will go to 100 percent. The service indicator light should go off.
The can with a drip is the oil indicator. If the light comes on, check the oil level (well, you should check the oil at least once a week).
Most Mercedes Benz Techs will suggest replacing your battery every 7 years.
Speed sensors generally are not serviceable. The sensor needs to be replaced. It should be an easy change out, either bolted on or screwed in.
It doesn't have a timing belt...it has a metal timing chain...these do not standardly wear out for a very long time.
Take your auto to your local Merc Shop and they should be able to reset your cpu for free.
if you haven't replaced the pad please do. If it persisits, apply anti-squeal paste. Should it persist further, reline the rotors.
The engine does not have a timing belt. If you are referring to the serpentine belt (the long belt that runs around the pulleys), it should be replaced when it shows sign of age. I replaced mine at 65k miles and it looked new. I hear people replace them anywhere from 80k - 90k miles. once
Check alternator output with a voltmeter A fully charged battery should read approx. 12.8 volts without engine running Should read approx. 13.8-14.2 with engine running
A few drops of any indicator is generally enough to get a reading.
The color the indicator needs to be depends on what it was when the desiccant was fresh. If the indicator color was blue, then it will turn pink when saturated with moisture. If the indicator was orange, then it will turn green as it absorbs moisture. So, the desiccant cartridge will need to be replaced if the indicator is either pink or green. FYI: The desiccant indicators that turn blue to pink contain cobalt chloride, which is toxic. The orange to green alternative is non-toxic. Source: http:www.silicagelpackets.com
acid should be a bright pink colour when using the indicator and alkali should go a greeny colour :) hope this helped you