The engine fan is not coming on at all.

 

Ok, Look for:

1) Low voltage from battery when the key is turned to "on". What I mean is, measure the battery feed voltage at the ECM. Low-ish voltage at the ECM will cause a no-crank. I don't mean just measure the battery voltage under "ON" conditions, but measure rigth at the feeds to the ECM. Use the service manual to find what battery feeds there are, I believe their are two.

2) In manuals, you want to verify the clutch interlock switch.

3) I believe that, in autos, there is a park-neurtral switch, in fact, I know there is, I believe it's part of the SLA (Shift Lever Assembly). Verify it's operation.


Now, you can take the Pulse module out of the fuse box, pry the cover off, turn key to 'on', and manually close the relay (there are two, one for the SRT circulation pump, one for the starter). If closing this relay makes the starter engage, you know:
A) The starter/etc. is OK.
B) The issue is somewhere in the intricacies of the electronics between the starter contact on the ignition switch/the ECM/the Pulse module/etc.

If you have not done so, it is time to download the service manual and start tracing where your problem is.

 

Have you made sure you have a good ground connection ,, if it is not good ,,,your lights will come on but car will not crank. take jumper cables and run one from batt negative to the engine. it will appear as a low or bad batt. these cars need one or two extra grounds to engine to frame/ body. jim

 

Since I don't have any diagnostic tools of my own I took the car to the Chrysler dealership in town. They just left me a message saying the problem is in the screem unit. The message said they need to order it from the Mercedes dealership at a cost of $635. Add 3 hours of labor and their total estimate comes to $1028.

1. can these screem units be fixed? By who and at what cost??
2. my car was not exhibiting the symptoms for screem failure that I've been reading about. (start briefly and shut down 2 times and nothing on 3rd try). Should I be concerned that the problem might be mis-diagnosed??

 

I did not see the request to use a scan tool. No Crank issues seldom set any trouble code - I would have argued with Zip over that recommendation.

In any event, I would not worry about a misdiagnosis - it's a dealer, OF COURSE they have mis-diagnosed it. We all know what a bad SKREEM does, it causes the engine to crank and start three times, then you get NOTHING until you disconnect the battery - then you get three more cranks. If that is not what you are fighting, then that is not the issue. DID you try disconnecting the battery to see if you got three cranks? (Seems to me you did and nothing changed, indicating it's not the SKREEM.)

If it IS what you are fighting, SOS can fix it if you send them the SKREEM, ECM and key(s) for around $600, I believe.

 

I'm NOT undermining anything Pizzaguy is recommending and I like the post above from amx1397.
I am wondering if your siren works when you push the red panic button on your FOB. If you get no loud siren then you should try to start your car with fuse #9 removed. It is a quick easy thing to try and cost nothing. Remove the negative battery cable, remove fuse #9 from the box under the hood and wait a couple minutes before re-attaching the battery cable. Then try to start your car. Could be that a bad siren has fed back into the anti theft system and is preventing the car from starting.

Unlock your doors with the FOB before you disconnect anything. If your still in the same no start situation after trying the fuse 9 removal, just put it back and continue trouble shooting.

 

How would I get a hold of SOS to discuss my SCREEM issue??

 

(503) 266-5442

 

Zip439 - I DON'T get the siren when I push the panic button so I tried to start the car with #9 removed. Nothing changed. Question is: Why doesn't the siren (alarm) work when the button is pushed??

 

My car was at the dealer for 6 weeks waiting for a new skreem unit. I finally got tired of waiting and had it towed home with the thought of removing the skreem myself and sending it to SOS for reprogramming. I'm still concerned that the skreem may not be the problem based on how the car acts. It does not give me the "3 crank" routine. It won't crank at all! Should I go to the trouble and expense of removing the skreem and having it tested by SOS?

 

Not before you answer my post #22. I am still not thinking this is a SKREEM issue, as you said, the symptoms do not line up with a failed SKREEM. The system was designed to let you know if the SKREEM is inhibiting a start - the ECU is programmed to do the 'three cranks and nothing" if the SKREEEM fails to authorize a start.

You have NO STARTER ENGAGEMENT at al, from what I read. A failed SKREEM won't do that and I don't give a damn what the dealer says. (Unless there is some undocumented failure mode of the SKREEM/ECU interface that we have never seen here in the eleven years I've been here - what are the chances of that?)

Go to post 22 and do the test I outlined. If pressing the relay does not cause the starter to engage, we have what will be a rather easy thing to fix - your starter or solenoid is bad (very rare but who knows?)
If the starter DOES engage, it will be interesting to see if the engine also starts - if it does, we have a fundamentally simple failure between the ignition switch and ECU/Pulse module.

From post 22:


Now, you can take the Pulse module out of the fuse box, pry the cover off, turn key to 'on', and manually close the relay (there are two, one for the SRT circulation pump, one for the starter). If closing this relay makes the starter engage, you know:
A) The starter/etc. is OK.
B) The issue is somewhere in the intricacies of the electronics between the starter contact on the ignition switch/the ECM/the Pulse module/etc.

 

You have to hold the siren button down for a few seconds to make it work. If it does not sound, the batteries have gone bad inside your siren (there are two small batteries inside the siren itself) and they may have corrupted/corrosion the anti theft system which prevents the car from starting. Did you disconnect the battery after you took fuse #9 out ??? By disconnecting the battery you reset the alarm codes (READ again my previous post) leave fuse #9 out and then try to start the car. If that doesn't work proceed as Pizzaguy is telling you.
The siren is located under the plastic cowl which is under the windshield wipers. Good Luck.

 

I removed the negative battery cable before I pulled the number nine fuse. Then I reattached the battery cable and tried to start the car. It did not start.

The siren is not working. Based on what you’re saying it sounds like I should try to fix the siren to see if that also fixes my starting problem. Does that make sense? Should I do that before following the instructions pizza guy gave me?

 

Is the pulse module in the same fuse box as the RCM? Is there a picture that can be attached to your reply?

 

It is not necessary to pursue the siren anti theft line of reasoning any more. If the car did not start with fuse nine removed continue with Pizzaguys troubleshooting advice.
Some people have replaced a non functioning siren and some others have simple disconnected the wiring connector under the cowl and drive without a siren anti theft alarm. It does no harm to have the siren disconnected. However, some time in the future you should replace or disconnect. The internal batteries will continue to leak, but they are not likely to escape the plastic cover in which they are housed or cause any other damage to components under the cowl.

PS The pulse module is located in the fuse box on the side near the fender.

 

The siren cannot make the car not start, as Zip said.

Now, when you dig into the pulse module, make DAMN sure the car is in "Park". If its' a manual , it better be in neutral and the parking brake set - pressing on that relay will engage the starter, all the Park/Clutch/etc interlocks are NOT EFFECTIVE when you manually press on that relay. Be damn careful.

 

I disagree with Pizzaguy about the siren. When those sirens age the internal batteries leak and the resulting corrosion on the board can feed back into the anti theft system which will prevent the car from starting. The anti theft system locks out the starting as it is intended to do should someone jimmy open a door. The batteries do not often cause this problem, but on occasson it has happened. Several members on this forum have been told their SKREEM module is bad after they could not get their car to start. They pulled fuse #9 reset the codes by pulling the battery cables for a minute started their cars and drove away. I am not saying it is a common problem, but it has happened, and in the spirit of checking all possibilities, this being such an easy and quick process, it is foolish not to give it a try, I quote from the Chrysler Student reference book "The Vehicle Theft Alarm system sounds an alarm siren, flashes exterior lamps and disables the ignition system when the alarm is triggered." I feel quite certain a corroded corrupted board on the siren can trigger the anti theft system.

 

Your quote has nothing to do with the matter at hand, this car has diodes to prevent the back feed of erroneous currents and with the alarm wiring similar to other models of Mercedes I am sure that if a diode was needed it would be there.
The siren is set of by the security system and is not likely to set of the security system itself.
I'm with the pizzaguy on this matter.

 

here is a picture of the pulse module. When I When I close the relay on the left nothing happens. When I When I close the relay on the right there is a fairly loud click under the engine, which I assume might be the starter. It almost sounds like the starter is trying to engage but is locked up. Any ideas?

 

My car was doing the same thing. My fan didn't speed up wouldn't start all lights on. I put a new RCM on runs great.