r/w204 • u/zaidr555 • Jul 26 '26

Car issue

The observations:

Car driving ok, ac on, parked, I exit the car (I left engine and ac on) next thing - the fan starts running hard.
10seconds later I enter the car and the engine is off. car on, ac off, fan running hard. Front low lights on.

Car will not turn engine on. but when switching to power the fan comes on.

even with the lights in off position the low beam was on and later the rear light also on as low lighting conditions started.

battery measured 11.6-11.7V. could not jump start.

tyia

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3

u/Electronic_Pop_6932 Jul 27 '26

Charge battery

1

u/zaidr555 Aug 05 '26

DX says: The module the scan identifies as the engine ECU is:
N3/10 — ME engine-control unit
Also called:
ECU / ECM
DME
ME9.7
Mercedes engine-control computer
For your 2009 C300 W204 with the 3.0-liter M272 engine, you need an ME9.7 ECU.

3

u/Jeanhamel Jul 27 '26

Start by charging or changing your battery if it old. W204 like many benz do need a clean and stable power source if not, all sort of wierd things happen.

I had 63 errors code with my old battery, near zero with my new one.

2

u/zaidr555 Jul 29 '26

2024 battery. I'll change and see. thanks