No crank no start compilation

Wayne B

New member
Thank you both for your suggestions. As it seems to recover on it’s own after 15 min and it has happened 4 times, to me it seems unlikely it is something like a corroded fuse box which would be unaffected by temperature And would fail and stay failed and not recover after 15 min.

So until it does not start, it looks normal, turn on the key, Glow Plug comes on briefly, turn key to next position and nothing…… Where is the ECU computer is it the box in the engine compartment?

My current theory is that it is something in the engine compartment.



I think the glow light coming on means this is not the same problem I had. But I should add, my problem was similar to yours in that it occurred when the vehicle had been parked for a while, then cleared up on its own in a few minutes. I have no specific theory as to why, except that corrosion in electrical contacts often leads to random intermittent problems.

In my model, the ECU is the box on the driver's side wheel well. It has a large multi-wire connector on it.


After further thought, I do have a theory about why the relay contact corrosion appears to be heat related. When a relay is activated, the current through its coil warms it a bit. When the ignition is off, it cools. The very slight expansion and contraction of this cycle could be enough to make the connection flaky. Well, it's not much of a theory, but its mine, and I'm sticking to it. lol.

If your engine compartment search doesn't turn up anything, you might look at the starter relay. It is activated after the glow plugs, so my glow plug light test doesn't apply.


Also check the ASR, (Automatic Stop Relay) which Dennis called out. It's never called that in any MB doc I've seen. Probably identified as R8 in the relay chart, although I haven't looked at the 2016 layout. It seems like a problem with this relay might prevent the glow plug sequence, but I don't know.

Another thing to add to the list, apparently, is that corrosion on fuses can knock out the start sequence. Even though this is in a "click no start" thread, it may be relevant to no click no start, depending on the fuse.

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