First of all i'd like to let You know this is a recap of what i went thru fixing my wife's ml350. It is starting right now with no more issues.

The reason why i decided to share how i was able to fix it, its due the weird circumstances that sourronded my diagnostic (wrong one by the way).

So let me take you to the journey...

My wife reported to me that the ml350 was slow on crancking, and that she believed it was the battery. Funny thing later reported that it would not cranck at all unless it was cold.

if for instance she was to use the ml350 to go to the store, it would cranck no problem and then when se came out of the store it would not unless she waited 15-20 min..

Due my previous experience with starters i believed it was just failing...

it was not until i drove it, and happened to me that i decided to open the hood and swap a couple of relays, obviously i included the starter solenoid one.

No difference.

I then figured it was the starter solenoid that would just quit when warm.

Being as smart as i think i am ..... I decided to order the starter....

(Wrong move)

after an hour and a half probably, i had the new starter installed and decided to give it a try....and guess what???.....yeap you are right, it did not work, as a matter of fact the car was cold and the starter did not cranck at all, it only made a click sound, the sound that you hear when the solenoid comes out, but the starter does not turn.

I pulled my hair, but not too hard since there are not much left, and went to grab my multimeter. I checked the battery voltage and compared it with my other benz. it was +/- .2 difference, do not recall which of the two.

This of course made me believe there was something else wrong.

I then decided to take the relay out and build a jumper to do the action of the relay...the starter cranck no issues........
at this point I'm thinking ..eureka, it is the relay! or the voltage that feeds the relay!

Wrong again....

I checked the voltage that actuates the solenoid relay, on one side we have 12V that come from another relay that feeds the whole circuit 15.

that relay (the second one) was good, and the circuit or system 15 had power everytime you open the ignition key.

then i checked the ground signal that goes to the solenoid relay (the forst one)...well that signal came from the main computer.....

Took the computer apart, found the schematic, trace the connection to a surface mount circuit, and then reheated the solder just in case there was some cold or crack between the circuit and the connections.




no luck!!...

at that point i'm already googling the price for a new computer and found one with the same part number for 185 bucks......and another new one for 2400 dollars!!

decided to see if the voltage was coming out of the ignition switch to the computer, to be able to blame the computer for sure.

Switch was ok...

decide to go back and measure the voltage that came to the starter solenoid relay while trying to crank it.... voltage there for only one second...no wonder i would hear that click!...the signal would not last longer!!

In my crazy head.....i'm thinking on a signal that should exist that tells the computer to stop crancking due the engine reaching the correct rpm...

Finally, when trying to cranck the ignition, realized the display showed a starter error!

Starter googling, but nothing made sense....nothing until.......i came up a post of someone , can not recall who..... but I sure appreciate it. that mentioned that batteries act weird on this cars.....

I though again, the battery is good because the voltage is good, and when i jump the relay the starter works! sure it is not my case!!

WRONG again!!

Just for kicks i went and parked my other car next to the ml350 and used the jumper cables to see how it would react....

The ml350 cranked!!!! but it did not start....

I knew i was on the right path, and by then i had read that the system protect itself for a while from that starter error.....so I decided to disconnect the battery for 5 minutes, and the reconnected it using still the jumper cables.

Voala!!!! it started no problem!!!!....shut it down and went and bought a battery......installed it and between the new starter and the battery the ml350 just starts in no time!!........but wait.......a battery....mmmmmm...wonder what my wife suggested it was to start with.......perhaps a battery?...maybe not.....can not let her know she was right......

 

When "Start Error" appears in the odometer window you have a problem with the DAS (Drive Authorization System) Module. It is housed in the EAM Module.

Sometimes you will be able to start it and sometimes not, but in any event a M/B dealer is the only one who can replace and program this module.