I'm at a point of confusion concerning the operation of a faulty SKREEM! My '05 XF, "sometimes", has the "classic" 3 times no start and then totally dead. "SEEMS" like if the SKREEM module was bad it would be bad all the time not just sometimes! I put a new RCM hoping it was going to fix my problem but has the same results. Grounds are clean and solid connections. Anyone know if there is something else that could be checked for this intermittent starting problem? Hate to spend $400 or $500 for SKREEM repair and not really being the problem! Any suggestions from MSS would be greatly appreciated.

 

Have you replaced the RCM?

 

You may try to get a scan from a DRB III scan tool, next time it refuses to start. There are several good repair people in Florida who may be able to help you with this.
There is also a product which you may want to purchase and give it a try yourself before moving on further. "DeoxIT D5" is more than just a contact cleaner. I have used it with great success on my audio gear. Disconnect the SKREEM electrical connectors give them a blast with DeoxIT. A decent scan should help determine your cause whether it be pulse module, SKREEM, PCM, CPS, or what ever.
Are you disconnecting the battery for a reset after the failure to start, just to get back on the road?

 

Sounds like a bad SKREEM to me. This would not be the first time a SKREEM went intermittent. There are many failure modes of the SKREEM, as there are with any electronic component with SMD devices on the boards.

I'd talk to Josh at the Mercedes Swap Shop and see what he thinks. Keep in mind, the SKREEM does two jobs, it contains the radio receiver for the FOB's lock and unlock buttons and sends processed commands to the CLP/SSM. It also, when you turn the key on, comes to life and sends EM energy to the key fob thru the black ring, the chip in the key responds with a signal that the black ring hears and sends to the SKREEM, the SKREEM then sends uses that data to give the ECU permission to start.

Perhaps the switched power to the SKREEM that powers the second function is failing at times (bad ignition switch?) I doubt that is the case. But fact is, the SKREEM does two jobs - do the lock/unlock buttons always work or do they sometimes give you trouble as well?

 

Yes, as I indicated in my post.

 

Yes I talked to MSS when I asked for a quote and he also said that based on my classic info that it indeed might be a faulty SKEEM module. He said that next time I get the no start conditions to remove the battery ground for 15 seconds and then reconnect. If problem still persists it "is" the SKREEm module. It has been starting several times properly today. I also am ordering a second key/fob from MSS. Just gotta find time to "RIP" my modules out of the car. LoL Thanks Pizzaguy! I can't figure out how you have soo much time to answer so many of our technical questions! Thank you!

 

Why don’t you try this:

Turned the key with battery disconnected to drain the capacitors. Then connected battery, turned key to on position for several minutes, sounded like things were reprogramming themselves, then turned key off for one minute. Then started car as normal.

If that doesn’t work then disconnect the battery with both cables touching each other for 15 minutes, tape them together if you have to.

 

Today it has been starting several times. Should I try your suggestion next time it fails to start or anytime?

 

I would say try those two things if it fails to start again, one at a time until it fails again or hopefully never fails again. Keep us posted. Good luck.

 

Bad relays in the RCM can give the same symptoms.

 

Last couple of days it has started every time. As mentioned I already installed a "new" RCM. Went for a drive this morning and all is still good for starting. When I parked at home "NOW" I have the stuck key problem and the key is stuck in the ignition. The key starts turns fine and starts the car but won't come out of the switch! The steering wheel does not lock either when is the off position. Hope I can get at that little trap door and remove the spring and pin to let the key come out. (If that has anything to do with the problem.) While doing that I'll install the new seat relay.

Second thoughts might it be a tumbler problem instead????

 

You already suggested this and he already replaced the RCM.

 

I was able to remove the column locking assembly. When I tried removing the FOB antenna ring it would not pass over the stuck key. I fumbled around with it and the tumbler locking nut, below the antenna, moved and the key fell out into my hand!!! So my question is what is the fix to keep this from happening again. Should I remove the spring and pin under the little trap door?

Update: Looks like the tumbler locking nut had nothing to do with the key coming out.
Update: There was no pin or spring under the trap door. Looks like it came from factory that way!

Side note: Installed new seat relay, while I could get at it, and the seat works again.

 

Thanks, I guess the RCM did the trick. Yes, remove the pin and spring, you do not need them. Did the wire on the black ring come loose?

 

No the RCM did not do the trick. It still has the intermittant no start problem as posted in #1.

With the lock assembly removed I can't get it to duplicate the key stuck in the lock problem! Anyone know if this is faulty tumblers in the lock? Would dry lock lubricant be advisable?

 

Do you even read the previous posts? He changed the RCM and has the same issue. You seem to be on a quest to answer every single thread.

 

The antenna ring pops on and can move a little bit. It is attached to the skreem. If you glue it on there then you will have to break it off later. I think Mercedes still sells them. When it comes to ignition switch situation, yes finish performing the sticky key fix so this doesn't happen again.

 

I now don't think the black tumbler locking nut had anything to do with the key being stuck inside the lock. Can't get it to get stuck again! Maybe one of the tumblers doesn't retract all the way and causing the key to get stuck. WHAT NOW TO DO????? Put it back together and hope it doesn't happen again?!?!

 

Dude, you won the lottery that were able to get the key out, most of the time people never get it out again until they start drilling! Remove that pin and you will never have that problem again, there is nothing wrong with the tumblers. Do exactly what is listed in the sticky key fix.

Then if you car acts up again when starting, try those 2 suggestions from me.

If not you will have to send keys, skreem and computer unless you can find a locksmith nearby that knows how to work on them. These days anybody can buy the software and equipment to make keys and work on skreems so you never know.

Josh is highly recommended by everyone.

 

Post #11 said otherwise but I know when my efforts to help are not wanted. I hope the two of you figure it out.