C180 Kompressor dies while driving

[Vlad_Tony]

Hello gentlemen. I have a 2004 W203 180 Kompressor. In the past 4 years I had it, it randomly completely shutdown while driving. After 10-15 minutes, it starts right back up like nothing happened. This happened to me maybe 5-6 times, at low speeds, while slowly braking. Last week, while doing maybe 15kph, it completely died and would not start at all. Below are all the details, I have to mention the battery is good, I've tested it, and about 6 months ago I went for a yearly check and all the diagnostics came out perfect. The car ran perfectly besides randomly shuting down while driving.

What do I mean by COMPLETELY SHUTDOWN? While driving, the engine dies, power steering gone, but the wheel is not locked, no dashboard, no hazard lights, not a single button works. When I take the key out of ignition to try and restart the car, the key just wont turn (it doesn't make the noise that the key has been recognized. The key doesn't unlock or lock the car either. When I try to unlock it, the headlights come on, the reading lights inside the car come on, the trunk and fuel door lock and unlock, and the radio works. The doors don't unlock or lock, I have to use the physical key to get in the car. When I get in the car, the whole dashboard (cluster) is completely dead (it usually turned on the display when you opened the door). It's been 5 days since it dies and nothing works.

What I've done to the car:

-2 years ago I went to a guy that said he knows what the problem is (after it dies 2 times) and he said he changed something regarding the ignition system to make the car recognise the key (but won't tell me exactly what he did, and also at that time the car ran).
-I took the circuit board out of the key, cleaned the IR sensor and changed the batteries for both keys, still nothing.
-I checked the battery and the fuses, all seem fine and dry

THE WEIRD THING is that when it dies, the dashboard gets stuck to the moment it shut down. I will attach a picture so you can see what I mean.

It seems the car just froze in time, Since I can't turn the key or do anything really, I don't know where to start. I've seen some people say it's the fuel pump (I'm on half a tank currently), the CPS, or battery lines. All valid, but it still doesn't explain WHY it dies WHILE DRIVING.

I don't think it's the key, clearly it's something electric, I hope it's not the EIS and if someone can help I would be so so thankful. I will answer any questions if anybody is kind enough to read all this. Thank you.

Video of car's current state:

 

[brandwooddixon]

A failing CPS will cause the engine to die at random intervals and be difficult to start until it has cooled down, but usually it will leave all of the electrics on - the last time that it happened to me was in an E Class as I drove around roundabout. I thought that the steering had broken! Loads of warning lights came up on the dash though and everything else electrical worked.

From the fact that you have some equipment that works and some that doesn't the failure point is obviously a common electrical component.
I suspect that there's a single event that triggers units to shutdown e.g. a relay trips out and won't re-engage.
List items that don't work other than just the ignition and those that do and people more knowledgeable than me may be able to determine a common point of failure.
For example radio works, ignition doesn't.

I've never seen an instrument cluster display speed, fuel level and rpm without anything else being lit. That may also be an indication of something. I suspect that the gauges are displaying the last values received over the CAN bus.
A CAN bus failure would knock out a lot of equipment and potentially cause the engine to die as the gearbox and engine ECU communicate to each other.
It wouldn't take much for something to take the CAN bus out due to holding a line at a fixed voltage.

Have you had earth points and straps checked?
Checked the ECU harness/plug for oil contamination? Unplug from the ECU to check.
The front fuse boxes look a little dirty inside from your pictures, any sign of corrosion on connectors if you remove some fuses and relays and look underneath?