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2006 ml engine wont turn over

6K views 25 replies 6 participants last post by  aml500 
#1 ·
Hello
I have a 2006 ml500 yesterday while driving red battery light came up and engine shut down try to restart engine wont turn over please help I check the voltage on the main battery its at 11.8v also its a keyless entry so I have a push button to start when I try to start dashboard lights cames up but the engine wont turn I was told by mercedes to check the battery, alternator or it most likely the crank sensor but car its not even cranking so how it could be the crank sensor also never gave any problem starting before so I was wondering what could be wrong please if anyone have any suggestion let me know thanks for reading.....
 
#2 ·
11.8 is too low battery voltage. Red Battery light is usually failed Alternator or broken drive belt, Alternator not turning.

Is drive belt still on pulleys?
Disconnect negative battery cable and charge battery till you have at least 12.6 volts
Crank sensor is not issue if starter is not spinning
 
#3 ·
I would first ask how old the battery is. It's doubtful it's the original. If you're not getting a charge, then it will pull down fast which will prevent cranking. I would check by removing the battery and charging it. If it won't accept or hold the charge, then battery may be culprit. But, I strongly suspect, judging from you saying battery light came on while driving, that you're not charging. I would then suspect the voltage regulator on the alternator as the culprit. Rarely do the alternators themselves go bad.
 
#5 ·
Hey thanks everyone belt still on the pully I dont know if its original battery since was used car all electric work fine on the car I remove both ground and postive from the battery for about 2 hours still nothing but I wont even crank with 11.8v alternator will be checked but its not even cranking keyless entery its push button where can I put key manually. ????
 
#11 ·
11.8v is low but should crank a vehicle. at least slow crank. if really low you would still hear the starter clic out. to me it sounds electrical but that just a guess with the facts you gave. if the starter is not getting a signal to crank, it will not crank.
low batt volt - car still cranks,slow
bad belt or pulley - still cranks, still starts
bad alt. - still cranks still starts
not saying to rule anything out but it sounds like something else.

did everything else electrical work? i.e windows? door lock? radio?

it could be that your keyless-go module is not seeing the key...
 
#16 ·
You need to jumpstart your ML. The battery doesn't have enough charge to crank it.

If the battery light is still on, you may not get far. In this case, find somewhere you can plug in a charger after disconnecting the battery.

When the battery voltage falls too low, the electronics don't work, so the throttle and transmission fail. --> http://www.benzworld.org/forums/w163-m-class/1553397-warning-lights-no-power-battery-draining.html#post4428038

If the car won't run, you may have a faulty alternator.
 
#18 ·
hey there on my way to work i decided to stop by my dead mercedes i try and pull the start button as you suggested and trun the key while pressing the break but i wont hear any sound from the engine i quickly tested the battery it says 11.8v i tested windows, radio lights they all work fine also the shifter i can press to go N and park and i try to start while measuring the voltage and voltage dont drop since the key looks like not giving the signal to turn the engine. and not to for get i hear rotating sound which i think coming from the back of radio or dash somewhere there....what can i do to make sure my key is giving away the signal to start is there a fuse for that what can i do next :-(
 
#19 ·
hey there i just speak to some mercedes mechanic he knew the problem he said you drove the car with lights on and steering wheel was heavy bring the car and ill fix it just wondering if someone has an idea or i should tow it to his garage......thanks
 
#22 ·
Did you jumpstart it?

Connect the jumper cables, start and run the donor car for longer before you start your ML. The extra charge on your battery will get you further. Find somewhere you can plug in a long extension cord, a battery charger, and your ML for a few hours. Disconnect the battery and charge it. Drive it home or to a workshop.

Alternatively, hire a tow truck.
 
#24 ·
everything that I try already.
checked battery voltage after engine shut down was 11.8v
try jumpstart plugging positive and negative under the hood. Engine wont crank.
try second key.
try jump start putting booster directly on the battery. no crank
pull out the keyless button and try manually with both keys no crank.
check all fuses looks ok.
my shifter can move to park drive or neuter . try to start in N same wont crank.
 
#25 ·
If the car won't crank at all, then you must have a fault in the starter circuit.

The things you could reasonably check at the roadside are:
  • Battery terminals clean and tight (especially the negative)
  • Starter relay working. (You can bypass it)
  • Inspect the starter ground cable for corrosion
  • Call MB roadside assistance. They'll tell you if you need to tow it.
 
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