Tati

Hello MB forum members,

I have a C203007 which has been excellent for the last 2 years, but recently it started showing a rather awful behavior:
Some times ( in average 1 bad/5 good ignitions) it just doesn't start/crank!
All the LED on the dashboard are shown as normal (good) but when I switch the key on the 3rd level, nothing happens: It's dead/No movements (I guess that the starter is not ignited!)
If I keep trying, sometimes it cranks but sometimes it doesn't and I'm left with a dead car (until after some hours or days when it cranks again)!!!!!

I checked the battery (Voltage fine: 12.67V and 14.XX when ignited) + load check which is good.
I was told by an MB owner that it's probably the starter relay: identified as the "S" relay on the frontal electric board (see attached document).
So I replaced it with a genuine relay, but the problem is still the same!!!

Can anybody suggest the possible reason for this bad behavior???
I don't trust my car anymore and I'm afraid that it will die on me in the country side and leave me stranded!

Plutoe

I guess I would start from the starter and work backwards---A-- when you apply voltage directly to the starter does it start--yes or no!!

Tati

Thank you dear Plutoe,

1)Is there a way to feed electricity via an external cable to the starter while it's mounted? How ?

2) Can a defective ignition key lead to the same symptoms?

Thank you.

Plutoe

After I responded I forgot to mention that here we use lifts so the car is over head and we use a spare battery with cables---then simply remove all cables from starter---then using the spare battery cables touch + to + and - to - ===== does the starter turn over.

Yes a faulty key or ignition module will exibit simular hard to start conditions!

Tati

Thank you dear Plutoe,

I just want to make sure that it's not about an intermittent faulty ignition key before focusing on the starter.
I'm a bit confused about my ignition key since it seems to do all its functions properly (open/close doors, when set in place, Handshake seems to take place properly with EIS, steering wheel unlocks, all dashboard leds ON - everything looks good as usual- till the 3rd level when cranking/Not cranking takes place!)

If an ignition key is faulty, it shouldn't pass all those power tests/stages??? Or can it still pass them all successfully but still fails cranking/starting the engine?

cheers.

Tati

Hello MB users,

Does anybody have a good opinion about my question:

1) If an ignition key is faulty, can it show all the status LEDs on the dashboard as good when turning the key from level 0-1-2-3(start engine)) and still NOT cranking/starting the engine?

2)Can the system detect a faulty ignition key and flag it somewhere? / How to verify that an ignition key is good??

cheers.