No comunication with ecm,esp,steering

Depends on model. http://www.obd-codes.com/p1605

only an inspection can reveal which, have your brakes checked

1. If the ESP light on a Mercedes Benz stays on, try holding the ESP button down for a few seconds. If holding ESP down for a few seconds doesn't reset the program, it's time to head to your local Mercedes dealership for a repair. More likely than not, there is some sort of error with the steering mechanism which causes the ESP light to remain on. You don't have to be alarmed but it's best to get it checked out as soon as you're able to. Most Mercedes have a four year, fifty thousand mile warranty which is, literally, bumper to bumper except for maintenance service. But if the ESP light stays on, this will almost certainly be covered.
2. If your car goes into a spin and the ESP light does not come on, it's time to see that repair shop too. Your Mercedes electronic stability program is not working properly if the car does not take control when a spin is detected.

Read more: http://www.mademan.com/mm/what-esp-light-mercedes-benz.html#ixzz3g3ve2zV0

It is usually a ABS wheel speed sensor has gone faulty, but you would have to have electronic diagnostic done to read off a fault code (DTC) and maybe a live data scan . Hope this helps

Reinitialize the system. Close all doors. Start the engine and apply the brake. Turn steering to full left lock and hold for two seconds, turn to right lock for 2 seconds, return to center. Repeat that procedure a couple of times. Move car forward and/or backward at least 30 feet. If there is no reset DTC and no stored or registered DTC, the MIL should go out.

My battery light came on in my mercedes B200 2010. What could be the problem? is it dangerous?

Possible that the memory was reset and so the ECM is also reset. You need to check this out with the Merc dealership so as to reset the ECM without further damage.

2008 should still be under warranty. Call dealership or the 1800 mercedes number and have them fix it.

Sensors on thewheels are very sensitive, check to see if they were adamaged in the rack repair. The clunk sounds like something is loose if you narrow down where you hear it that would help, but my guess would be the idler arm.

I have similar problem with wife's B200. Am told it's the neutral/park sendor in the gearbox, which prevents car starting unless in park or neutral. Dealer wants AUD$1200 to remove gearbox to replace faulty switch sensor. Will update this website on repair outcomes.