benro1974

2009 c300

Can the front SAM be totally failed even without any obvious corrosion or water damage?

I have multitude of symptoms that have been progressively increasing.

Left front running light staying on.

Then cranking but not starting.
Then OBD2 scanner won't turn on.
Then not crankning.
Then radiator fan coming on at full speed.

Also checked the pre-fuse box and all fuses are good.

CaliBenzDriver

The beauty about these very sophisticated cars is modules can disfunction in cascade. Such as SAM helping crash networks.
To be honest it works almost right most of the time.

You can go ahead and reboot your car computers

you can scan your car for faults if not networking is seriously bad.... we can unplugg some crazy network branches at the front door threshold busbars.

TimC300

For the front sam there could be an issue on the circuit board that wont be easily visible just looking at it with the top cover off. Here's an example:




For the OBD port you said you checked the fuses but I would check them again. I think the front is fuse# 16, and the rear is fuse# 73.


Front


Rear:



Are there any signs of water getting in the car? Ive seen where water damaged the front sam. I just read a post where someones obd port wouldn't work and turned out to be water got in the car down on the carpet near the drivers side door and and got in some connectors.

benro1974

Yes, I looked at the circuit board and it looks perfect.

I am going the look at the connectors by the driver's side door. I do think it is water related. We get a lot of rain in Hawaii and the windshield wiper motor cover drains get clogged.


QUOTE=TimC300;8930917]For the front sam there could be an issue on the circuit board that wont be easily visible just looking at it with the top cover off. Here's an example:




For the OBD port you said you checked the fuses but I would check them again. I think the front is fuse# 16, and the rear is fuse# 73.


Front


Rear:



Are there any signs of water getting in the car? Ive seen where water damaged the front sam. I just read a post where someones obd port wouldn't work and turned out to be water got in the car down on the carpet near the drivers side door and and got in some connectors.[/QUOTE]