Was running some errands the other day when I need to make a quick pit stop back home. Let the car sit for about an hour and when I went to go back out and run some more errands, the car wouldn't start.

I can turn the key to run and it tries to but doesn't engage. After doing this twice the car will no longer attempt to turn over.

I thought it was the RCM issue because it's done similar things in the past and resoldering the contacts fixed the issue. I ordered a new RCM and put it in last night and it's still doing the same thing.

Anyone able to think of what else the issue may be before I have the car towed to the dealer under warranty?

Edit 12/9/16: Never updated with what the result was. I ended up having the car towed to the dealer where they replaced the starter and a solenoid. After those were put in they realized the SKREEM was bad and had to replace that. I think that is what originally the problem was and because I tried to start it so many times while troubleshooting it fried the other things.

 

Disconnect the battery for a minute.. try starting the car afterwards.. 2 more attempts and nothing.. look up Skreem Module..

 

I had the skreem module replaced about 2 years ago. Would it already have gone bad again?

When I drop in a new RCM it will only try to do it once before not trying to turn over again.

 

It's not impossible.. but the "almost" fired off and then nothing is the immobilizer in control.

 

Is there a way to confirm that to be the culprit? Or anything else that could be the issue?

 

No check engine light?

 

Just out of curiosity does he still have the original crank position sensor in it

 

As far as I know, yes, it still has the original CPS in it.

 

No, the CEL isn't on.

 

Well I can't say for sure that's it but mine was doing some pretty weird stuff too until I changed it and so far it has been behaving. I would check the usual things like battery connections battery cables ground cable ground connection to the fender well, eliminate what it's not and you will arrive at what it is.

 

If the CPS is out.. it will crank till the battery is dead.

 

Well I'm not saying you're wrong so let me give you some examples of what mine did, never fail to start when it was cold, on occasion it would stall when you came to a light or stop sign, sometimes it would start right back up but most often it would do nothing, no starter engagement no click no nothing, let it sit for 15-20 minutes and then most of the time it would restart, sometimes after driving for just a few minutes I would shut it off go in and run an errand and it would just turn over but engine would not start, would have to reset by removing negative battery terminal, in all of those times it had only thrown a code once , and it was the crank position sensor code. So I honestly don't know what to tell you these cars are very very quirky. When I pulled it out it was the original CPS still had Mercedes Benz on the side of it 11 years old and 110,000 miles.

 

Just unplug your CPS if you want to test this.. and see how many times you get "nothing" at the key. And any CPS that doesn't have "Mercedes" on it.. was replaced with the wrong one.

 

In the back of my mind I know you're right but I'm just trying to put off the inevitable because I'm a chintzy rascal and I don't like spending money. next on the agenda is a new RCM geez I hate spending money!

 

Why not just do the repair to your RCM? Much like you.. I'm not out to spend everything I can on the cars.. I'm waiting on an RCM for $5 and free shipping for a spare..

 

I would but I don't have the proper equipment for replacing the relays,
Resoldering the pins on the end of the board is pretty simple but desoldering and replacing the relays is beyond my 100 watt soldering iron. I should just send it to tighten 1.

 

We have not forgot about you krisfire, everybody's mulling it over in their heads trying to come up with something.

 

I just went out and disconnected and reconnected the battery and it won't attempt to turn over at all. Swapped back in what I thought was the bad rcm and still nothing. I read at some point you could manually close the relays on the board to test if they were bad. Would that be an option?

 

I will have to defer to the RCM experts on that question, but I believe I am correct in saying that when you turn the key to the on run position the contacts in the relays should close.

 

Ensure the 3 middle relays are closing.