Thanks for the responses. The car is a 2007 automatic with 70k miles on it.

Yesterday the car unlocked using the remote on the key, but first wouldn't start at all, wouldn't even turn over. AAA checked the battery and it was fine. I tried disconnecting the battery in case it was a related issue, and oddly, the car would then start to turn over 1-3 times, then die. Additional attempts to start the car without disconnecting the battery, the engine wouldn't even start to turn over. I didn't notice anything else strange, I could hear the fuel pump functioning normally. The automatic lock on the key remote still works, and the alarm isn't going off, so maybe this is not a skreem issue?

The reason I thought of the skreem first was the issues with starting in the last couple years. There have been no problems with it until the last couple years, and then just 3 isolated incidents where the car would start to turn over and die, each time 3 times in a row. The alarm would go crazy and the automatic unlocking on the key wouldn't work, the car would have to be unlocked manually. Each time, fully disconnecting the battery for a minute solved the problem and there wasn't another problem for 6-12 months.

With another car I would think it was a starter problem and take it to a mechanic, but I'm trying to prevent the situation where I take this to a mechanic who has no idea and charges me a lot to not fix the issue; generally my experience with issues with the crossfire starting!!! The closest person who is good with the crossfire is in Santa Rosa, CA, over an hour from me in Berkeley, so it would be good to know what I'm dealing with. Thanks for any thoughts.

Kara

 

Hi Kara,
It's been raining in California for the last couple of weeks. Do you have, or did you have water in your foot wells, or in the truck (convertibles have leaks that fill up the pocket that the clp sits in)? With the key in the "on" position, are there any dtc lights showing in the instrument cluster (IC), or is a message scrolling in the IC when you turn the key to on?

I think the symptoms for the common crossfire problems involving no starts or no cranks are:
1) Relay Control Module (RCM) - can be no start, no crank, no fuel to injectors - leaving the key in the on position can result in the radiator fans spinning at warp speed
2) SKREEM - usually, but not always, 3 brief starts and you're out - nothing happens (no crank, no start) until you disconnect the battery to reset the error, then you get 3 more tries.
3) Crankshaft position sensor (CPS) - car will crank but not start. Sometimes if the car cools off, it will start.
4) SLA (shift lever assembly) - spill a drink on the shifter, and the SLA stops talking to the computer. The computer doesn't know what gear the shifter is in, so it won't let the start enable go. (This usually shows a black rectangle in the instrument cluster by the clock when the key is in the "on" position.)
5) bad battery or charging system - anything can happen
6) transmission control module (TCM) - water pours into the passenger foot well due to clogged drains under the cowl - car may not crank or the transmission goes into limp mode depending on how badly corroded the TCM is.
7) Pulse module (PM) - starter won't engage (I don't think this is that common, but it's easy to check)
8) less frequent - CAN Bus fault - usually a broken wire which prevents the modules from communicating with each other

Not to scare you, but there can be a lot of reasons for a no start or no crank. The car does try to tell you what the most likely issue is either through DTC error codes, dash warning lights or behavior.
-Jerry

 

Hi Jerry,

Thanks for the super thorough reply. Car is kept garaged, so hopefully the rains didn't impact it too much. No abnormal lights on the dash or messages.

I did think I heard the fuel pump, so I was hoping that meant not RCM. No fan spinning at warp speed.

Skreem was my first hypothesis, since I have had a few skreem related incidents, but they were previously fixed by disconnecting the battery, and now disconnecting the battery does seem to reset something, since I get 1 or 2 half-turns of the engine out of it before I get nothing, but it doesn't fix things like before.

CPS - don't know about this, did leave the car for a day and try again, no luck.

SLA - no spills that I'm aware of, and I'm the only one driving it

Battery was checked by AAA and shouldn't be too old, but I could try replacing it.

TCM - not sure about this, I'll investigate this and the PCM.

Thanks for taking the time to list all these ideas; I will see what I can figure out and update in case others have similar problems.

So appreciate the help and love this forum. I'm the only 40 something woman I know working on her own car, and all the help I've gotten here is what has kept me owning the crossfire.

Kara

 

Just disconnecting the battery resets the SKREEM. It will give you 2 or 3 more cranks. Based on what you are describing, I think your SKREEM is done if all you get is 2 or 3 cranks, a start, then die, then NOTHING.
The real clue that it's the SKREEM is that you get 2 or 3 crank/starts then you get NOTHING until you disconnect the battery. THAT is either a bad SKREEM a missing RFID chip in your key, or a bad ECU.

The answer is to reach out to James at The MSS.

760 793-1372 or TheMercedesSwapShop@hotmail.com

 

Thanks for this. That was my hypothesis. Going to check out the other ideas first just to be sure, but I thought it meant something that disconnecting the battery would allow for 1-3 start attempts.

Only question about this -- previously skreem probablems also kept the key from unlocking the car remotely, and were associated with alarm going off. Is that not always the case with the skreem issue? Does the key still sometimes work remotely, just not to start the car?

Kara

 

Hi Kara,
From what I've read about SKREEM issues, it can manifest itself in a number of ways depending on how it's failed - for example, if the transponder in your key (BTW, do you have a second key that you could try?) somehow got scrambled - the FOB would still work, but the car wouldn't start. Same if the antenna ring around the ignition failed, or a part in the SKREEM failed that is only used on the transponder side. The good news is that you know you're getting power to the SKREEM and it's RF receiver works since it responds to the FOB. The SKREEM is talking to the BCM, and BCM is talking to the CLP to open and close the doors - means your CAN BUS is probably okay. Do you have access to a DRB III code reader? That might pinpoint it directly by reading the SKREEM DTCs if there are any.
-Jerry

 

No DRB3 or second key. It looked like there was a budget equivalent of DRB3 on Amazon, don’t know if it’s worth it.

thanks again for the ideas!

Kara

 

Hi Kara,
Depending on how computer savvy you are, a micropod II DRB III emulator runs around $150 and works pretty well. It runs on windows 7, but some say it runs on windows 10. There is a forum member who uploaded a virtual machine version (search for DRB III emulator in the forum search tool) , and I have that running on windows 11 laptop. It allows you to train the tire sensors (TPMS), reset the airbag fault and read all of the DTC from all of the modules. It even acts like a DTC II code reader.
If you go about repairing your SKREEM, there are two options available to you - send it out, get it repaired, or get the ECU reprogrammed to ignore the SKREEM - you lose some security, but now any key you get made will start the car. I think either option costs around $500.
Good Luck
-Jerry

 

YES.
There are two halves to the SKREEM.

One is powered by the battery via fuse 35. This part is always "on" and is the "Security System" part that operates the 300mHz receiver and listens for the FOB's signal, when it hears that signal, it tells the BCM to tell the Locking pump to either lock the doors and set alarm or unlock doors and disable the alarm.

The other half is powered by ignition switched power via fuse 37. This part is powered up when you turn the key to "ON" and is the "Start Enable" part that performs a very fast handshake with the RFID chip in the key FOB as well as the start enable part of the ECU.

Either half can fail.

 

Great, thanks. That’s helpful. A local shop read the codes for me, they said the computer read code P0271, and P0010 was stored in the skreem which they found odd.

Kara

 

That's interesting, a quick web search comes up with these results: the P0271 is related to a bad fuel injector, and the P0010 is related to the camshaft position circuit. Bad or low oil can be a cause. If you haven't already you should download the service manual from this site, and check what the codes mean for the crossfire specifically. I just replaced my crankshaft and camshaft positions sensors - two bolts, two connectors and you're done. I bought Bosch parts for both from Pelican Auto parts for ~$75 total. (Pelican Auto is located in northern California, btw.) It sounds like you're making headway.

 

Sorry, should have posted the meaning of the codes along with the codes. I did check them, and wasn't intending for someone else to need to look them up for me, I had been asked for them in an earlier post and was just sharing them in case someone knew more in terms of any relationship to potential skreem dysfunction.

Thanks for taking the time to let me know the info about crankshaft/camshaft position sensors; I'll look into it.

Kara

 

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General PSA, in case it hasn't been mentioned enough. These cars are sensitive to non-Bosch sensors in the CPS and CPS (cam and crank). Seems the connector pins are slightly different enough to cause no end of frustrations, and such. The saying is 'Go Bosch or go home'. Only a few cents more for the Bosch unless you get em on sale, be careful if the ad says something like replacement Bosch sensor, because it might be a replacement but not a Bosch. Thank you for your time!


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