Hello,
I don't know why my W221 shows so many error messages. The car began with these issues after a visit to an authorized MB dealer, and I believe they did a software update.
I replaced the main battery. I have no error message related to the hybrid or the small battery inside the dash. The hybrid battery is around 70% charged.
The car sometimes starts and sometimes doesn't. After it starts, it is drivable, and I don't see any loss of power. Turn signals don't work during errors.
The attached link will take you to a YouTube video. https://youtube.com/shorts/sffY8tEgPUo
What should I check?

 

check other posts - hybrids are BIG trouble and even bigger money to fix... post last week discusses how a company can convert it back to a real car for $8k - likely the cheapest solution for long term peace of mind

 

I purchased the car recently, and it only has about 38K miles. I will consider converting it if I can't find a solution to keep it as a hybrid. Thanks for the info. I did check online for a kit, and this is what I found https://mysupercarexpert.com/product...s400-to-s350-1

 

on another forum, chap with a merc hybrid can't get an AC compressor - because its an unusual much rarer type designed mostly to cool the battery not the people.... its parts like this they designed to die as its essential they work therefore the best bits to make fail... its not rocket science to keep them on the road... but as to how much of the car you have to dismantle how to diagnose, and how turn on the replacement part - they went even further down the route trying to make it a dealer only cure

the S (and indeed most premium cars) are designed for governments and or super rich to buy and maintain at (your) cost, for short periods then throw away, the last thing ever intended was for them to reach the slaves and be an affordable way to enjoy life

 

It could be the AC. I already purchased a diagnostic tool and shipped it to the EU for my mechanic to check. I asked if someone had similar issues where the entire dash lights up, and the car still runs. It can be many things that can go wrong, but it is better to narrow down to a few that are most common. As you said, AC, DC, hybrid battery, or power modules are just a few that are the most common.