This has been an on going issue for 4 yrs. occasional ESP, BAS error's drops into limp mode. some times when you insert the key panel lights up normaly but absoutly NO responce to start, no click on nothing. come back an hr. or so later and all is well. been to MB 3 times they replaces the trunk SAM; seam's to have made no differance. Done the steering wheel sinc trick and everything else I can think of. I need some good MB heads here to throw out some idea's on what to go after. PLEASE.
!!EDIT I FORGOT to mention 2 other things that might also help, 1 is an occasional rough idle at stop signs; 2 when the turbo fan starts it seams to be the time it throughs the ESP error's the most.

They're usually a stud mounted on the body with several brown wires going to them. There's a couple under the hood, and some in the trunk, and some under the dash. Sometimes loosening them, wiggling the wires and re-tightening them works, or you could completly take everything off, scrape them off, clean them up, coat them with grease, and put them back.

Anytime you loosen a ground connection disconnect the battery first.

Thank you, I will search for the ground locations and check them out.

This has nothing to do with bad grounds.

Get a scanner that can talk to all the computers in your car. The cheapest option is icarsoft i980 or mb2. When the problem pops up scan your ABS module for codes. Thats the only way to diagnose the problem definitively.

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Went to buy MB II scanner, got no responce from the company witn many phone calls and 2 E-mails, so am not going to do business with a company that is that lax with a sale inquiry. did try 4 other scanners including Launch and could pull no codes. I did clean all grounds; and relay, fuse,front SAM, and ESP/ABS connections, as well as battery connections. started it up and had a christmas tree panel! let it run for about 5 mins. shut it off, restarted it clean panel. took it to Mercedes; they found the ESP/ABS control module to be dead. Said it was the cause and also blocking the communications thru the other sam's and coulden't go any further in diagonestics until it's replaced. $1900. for the part! I found a complete brake unit for less than 200. used, will be here in a couple of day's. Any procedures recommended in changing the control module before I get at it. Thank You all in advance.

Why are you calling icarsoft? They sell the i980 for $100 on Amazon. It's an excellent tool.

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