MilosM3

I was dropping my car off at my mechanic's tonight so he can fix the trunk sensor.
My father was following me so I could have a ride home. As I was starting the
car in my driveway, I noticed that there was some hesitation with the
car turning. On the second time (also with 1-2 sec. of extra labor)
the car started.
I had to stop by at Home Depot first to pick some supplies. When I got
back in my car and turned the key - nothing. The RPM, gas and speed needles
flipped all the way to the right (for a few seconds - like they always
do when I start the car), but there was nothing. Engine did not turn, there
was no clicking of the starter. When I popped the hood and tried to start
again, all I could hear was very subtle and steady purring like I hear for
a few seconds when I get home and turn off the car. I guess this is hydraulics
priming that is powered by the auxiliary battery?

We tried to jump start the car (as I said, my dad was to be my ride home
from my mechanic), but attaching the jumper cables and trying to start
again did absolutely 'nothing' - same symptoms (no sounds at all) as when
I just tried to start normally.

I did not call a tow. It was only about two mile from my mechanic. (He
was out having a dinner and I was only dropping the car off). The car
is well lit and literally very first one to the main entrance. Manager
further assured me that they have night security patrolling the premisses.
I decided to leave the car there and will be meeting my mechanic there
SUN morning.

What are your thoughts? Starter? solenoid?....I hear it could be also
a bad main/starter battery, but if so why I was not able to jump start
it from my other running car (M3 with with only 2 month old battery).
Why there were no 'starting noises' at all while I tried to start or jump
start the car?

Thanks in advance for your input.

TwinCam

Sounds like a dead battery. Did you follow the correct jumping procedure as stated in the owners manual using the correct battery in the car? The car has 2 batteries and trying to jump the trunk battery can cause serious damage to the electrical system. You must only jump start using the under hood engine compartment battery and the engine and catalytic converter should be cool. Do not turn on the headlights under any circumstance while performing the jumping process, this means turning the headlight switch from auto to off. You can download the owners manual at MBUSA.com. It can be found in the owners section of the web site. Hope this helps! TwinCam

MilosM3

Thanks TwinCam, ...yes we were jumping the main/engine battery under the hood.

However, the battery is getting ruled out.
Brought this jump starter - same result - NOT a beep, car did not even
attempt to turn.



My guess is now that it is the starter or the solenoid.
Looks like the car getting flat-bedded to my mechanics's shop tonight ;-/

Wolfman

I had something similar one time with our SL55; it was the shifter thinking it was in drive (while the car was off), yet it was physically in park.

While the shift lever still looks somewhat mechanical, it it simply an electric switch.

Maybe it's not the same issue, but the effect sound similar.

Just reset the electronics by disconnecting the rear battery for a while and then reconnecting it. This will reset the system and it solved the issue for us.

After reset, remember that you need to reset the ESP and calibrate the window closing...