Hi All, I have a 2018 S560 4L twin turbo, 43k miles. I live in Northridge, CA and am currently having two problems.

The first problem I'm experiencing is that the engine is running very roughly at all rpms and has no power. The check engine light stays on solid. At idle I'm dreading the moment it stalls while I'm waiting to cross an intersection. You can just floor it and not much happens. The rough running engine issue happened twice before and each time the dealership replaced only one coil pack. The last time it happened the dealership said that they had to actually see it happen even though there was a CEL and codes present. I had to rent a car for 10 days before I got the car back since they did not have a loaner available. For the past three days I've been having this rough engine. The dealership does not have a loaner and I don't want to end up wasting my money renting a car for what is a free warranty repair. I feel like just buying the coil pack and replacing it myself but this just does not sound right in principle. I'm also hearing that these coils are not easy to get in stock so I would probably have to purchase an after market coil pack. There is a Mercedes bulletin extending the warranty of the coils because so many are failing. Any one experience this and have any suggestions on how to quickly resolve it?

My second issue happening now is a weird one. It has also happened once before about a year ago but was gone in about half a day. The vehicle starts in drive mode "C". I pull out onto traffic and the car stays in first gear. As soon as the rpms get to 3000 rpm the engine suddenly cuts out. Very scary when pulling into traffic because you're only limited to about 15 mph and are close to getting rear ended the first time this happens. I quickly learned that I could paddle shift before 3000 rpm and shift to 2nd. The trans would then upshift normally through the rest of the gears. When coming to a stop the the transmission would jerk into 1st around 15 mph. My understanding is that in "C" and "E" mode the transmission should not start in 1st but rather 2nd. In the "S" mode, the transmission also stays in 1st until paddle shifted to 2nd. Unfortunately this is intermittent because today the trans is working. Any idea what is happening?

Thanks for reading all this. I'm just a bit frustrated.

Have a great day!

Check your cam position sensor and cam phaser connectors for oil, if thats good an you DON'T have a constant or flashing check engine once the incident happens and you restart the car change your plugs and coils. This is an issue also with the AMG (M157) version of this engine I had, though it was the trans watched a vid on how easy it is to foul out the plugs on this engine. Changed my plugs and all issues are completely gone. Good Luck..

Thanks Bigg. The check engine light just stays on constantly. When I restart the car it is already on. I can't see why one of these dealerships just makes an appointment in the morning and lets me go in a few hours unless these are backordered everywhere.

Failing coils are actually a common issue for all coil-on-plug applications.

In our family, we’ve had coil failures in: Volvo S90, Nissan Murano (2x), BMW 328i (2x), E350 (3x), VW Passat.

After the second time, we bought an OBD reader, and we keep a spare in the garage for each car. Swapping a coil takes an hour max, and saves the time/$$$ of a trip to the dealer. Turbo cars tend to go through coils at a faster rate than NA cars. Since you’ve already had this issue, I’d get a scanner and swap that coil before resorting to a dealer visit.

Normally, the coils should last around 100k miles, but sometimes you find a weak one - and it fails early.

As for the 2nd issue: I’m stumped. Hopefully someone else has some insight there.

What dealer are you using? I've had good luck with Caliber motors in Anaheim, Star MB in Laguna Hills and Fletcher Jones MB in Ontario, stay away from Walter's MB in Riverside, I only do parts from them as I'm in Riverside.

I only have about 44K miles. In the last year I have already replaced two coil packs and now I have a third going out. I don't see why the dealership is only replacing one coil pack at a time at this point. They should just replace the remaining two. Anyone have a favorite dealership in the northern LA county area or even Thousand Oaks or Oxnard? I'm currently at Keyes Van Nuys.

Pauli, While it is a bit far from you, I have used Santa Barbara Auto Group (Google them) for years and they have always been good. Todd Smith is my long time service advisor if you want to try them. Good luck!

Please list the codes.

Replace spark plugs and coils if it hasn’t been done yet.

Battery should be preemptively replaced. The battery is coming up on 6 years old depending on build date. Less than 100% good batteries cause unexplainable problems on modern German cars.

Check for oil coming from the rear main seal area. This is an emerging problem with the 4.0TTV8. Root cause is failed oil vapor separators and can cause CEL and rough running.