How to Repair Relay Control Module (RCM) - (Mystery no Start)
Joined: Dec 2007
Posts: 16
Likes: 0
From: Fort Worth, TX
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Sorry for the late response everyone but the solder repair did 'take'...
Two days later I tried starting the car and it did. It has been running ever since, no issues.
Thanks everyone
FatCat
Fort Worth, TX
Two days later I tried starting the car and it did. It has been running ever since, no issues.
Thanks everyone
FatCat
Fort Worth, TX
Joined: Jun 2013
Posts: 5
Likes: 0
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I find this. Now go to check if there is problem. It looks not bad but also not good. I hope it will be the problem. Thanks for sending this solution. Already was in two servis and nobody know what to do with that.
Same as biggist autorized dealer of MB.
Same as biggist autorized dealer of MB.
Forum Regular
Joined: Jun 2012
Posts: 502
Likes: 0
From: Derby, KS
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
So if anyone is interested I have a old RCM that needs to be resoldered that I didn't feel like messing with. If anyone is interested in fixing it give me a PM with an offer. I know a new one goes for $125 + shipping. So if anyone is interested let me know.
Joined: Jan 2012
Posts: 5
Likes: 0
From: Kingswinford UK
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Thank you for this, had the problem for about 6 months always got away with a wiggle of the box, finally found time to do
FIXED :-)
now onto the alarm/hazards fault... off to the boot (trunk) for a look around
FIXED :-)
now onto the alarm/hazards fault... off to the boot (trunk) for a look around
Joined: Aug 2012
Posts: 5
Likes: 0
From: Pittsburgh
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Where did You buy the RCM? I think my 05 is experiencing this problem, but it behaves slightly different than described here. I had my 05 limited shut down at an intersection. when I turned the key, all the warning indications came on at one time. cranked the starter, the starter would turn over, but not start. turn the key back and the starter is still cranking! turn the off. Wait a minute, then it starts fine. Got it home ASAP and it's been in my garage since.
Anyone experience this?
Mike
Anyone experience this?
Mike
Senior Member
Joined: Dec 2010
Posts: 12,780
Likes: 185
From: Lineville, AL
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Where did You buy the RCM? I think my 05 is experiencing this problem, but it behaves slightly different than described here. I had my 05 limited shut down at an intersection. when I turned the key, all the warning indications came on at one time. cranked the starter, the starter would turn over, but not start. turn the key back and the starter is still cranking! turn the off. Wait a minute, then it starts fine. Got it home ASAP and it's been in my garage since.
Anyone experience this?
Mike
Anyone experience this?
Mike
Replace with a Boshe, accept no substitutes.
( the RCM - K40 symptoms is you turn the key, get dash lights, then go to start position and get nuttin )
Senior Member
Joined: Jun 2008
Posts: 1,928
Likes: 26
From: Spacecoast, Florida
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Where did You buy the RCM? I think my 05 is experiencing this problem, but it behaves slightly different than described here. I had my 05 limited shut down at an intersection. when I turned the key, all the warning indications came on at one time. cranked the starter, the starter would turn over, but not start. turn the key back and the starter is still cranking! turn the off. Wait a minute, then it starts fine. Got it home ASAP and it's been in my garage since.
Anyone experience this?
Mike
Anyone experience this?
Mike
If she's turning over, it's not the RCM. It's probably the Crankshaft Position Sensor. Has happened to many of us in the exact same way. Here's the link to a 20 page sticky on how to easily fix this common problem...
https://www.crossfireforum.org/forum...on-sensor.html
Joined: Aug 2012
Posts: 5
Likes: 0
From: Pittsburgh
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Thanks Guys for the quick reply! This car is my wife's baby and I can't have it dying in some of the more interesting neighborhoods around 'da burgh...
Off to the CPS thread! Then next got to fix the door pull.
Mike
Off to the CPS thread! Then next got to fix the door pull.
Mike
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 26
From: Kellyville, Ok
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I'll bet 10 bucks you have an automatic too! If you just bump the start position and let go of the key it will crank "by itself" for a few seconds.. totally normal..
Senior Member
Joined: Jun 2008
Posts: 1,928
Likes: 26
From: Spacecoast, Florida
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Mercedes Crankshaft Position Sensor - Bosch 0261210170 | FCP Euro
--------------------------------------------------------------------------------------------------------------------
And for the exterior door pull ....
https://www.crossfireforum.org/forum...-2-screws.html
Last edited by syfi; Jul 8, 2013 at 09:45 PM.
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 26
From: Kellyville, Ok
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Good price for the recommended Bosch CPS w/ free ship ....
Mercedes Crankshaft Position Sensor - Bosch 0261210170 | FCP Euro
Mercedes Crankshaft Position Sensor - Bosch 0261210170 | FCP Euro
Joined: Aug 2012
Posts: 5
Likes: 0
From: Pittsburgh
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Mike
Joined: Aug 2012
Posts: 5
Likes: 0
From: Pittsburgh
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Good price for the recommended Bosch CPS w/ free ship ....
Mercedes Crankshaft Position Sensor - Bosch 0261210170 | FCP Euro
--------------------------------------------------------------------------------------------------------------------
And for the exterior door pull ....
https://www.crossfireforum.org/forum...-2-screws.html
Mercedes Crankshaft Position Sensor - Bosch 0261210170 | FCP Euro
--------------------------------------------------------------------------------------------------------------------
And for the exterior door pull ....
https://www.crossfireforum.org/forum...-2-screws.html
Mine is the interior door pull. Sorry for the confusion.
Mike
Senior Member
Joined: Apr 2006
Posts: 25,432
Likes: 650
From: Ontario
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
The RCM's are wave soldered, a fast method of doing the soldering on PCB boards. It does have its faults though.
Wave soldering method.
Faults found on Wave soldered PCB boards.
Wave soldering method.
Faults found on Wave soldered PCB boards.
Last edited by onehundred80; Jul 21, 2013 at 03:47 PM.
Joined: Jul 2013
Posts: 2
Likes: 0
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I am a new member and have been reading the posts about replacing the RCM. Ordered one from Mercedes and will replace this weekend. Any programming have to be done or just replace?
Senior Member
Joined: Sep 2011
Posts: 9,595
Likes: 26
From: Kellyville, Ok
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I'll tell ya if you'll send me your old one! 
Typically these are highly repairable, but no... it will plug right in and work fine with the system.
Typically these are highly repairable, but no... it will plug right in and work fine with the system.
Joined: Jun 2009
Posts: 32
Likes: 0
From: Richland, WA
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I think my RCM just went went on vacation 1 month got home no start .... Grr I'm going to replace battery first as it is under warranty still hope that's all it is ... Wish me luck!
Joined: Jun 2009
Posts: 32
Likes: 0
From: Richland, WA
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Well changing the battery didn't work , I do have all dash lights when I turn key... No start so I'm going to try to see if it is the RCM it doesn't look too hard to take out and look at ill give it a try.thanks to Tighed1 I at least have a starting point then if all else fails off to local shop. hope NotThe car is a 2005 49,000 miles last year had the infamous key ignition problem locking pin problem. Lol
Well thank you for this great forum and ill keep you posted on any progress... bill
Well thank you for this great forum and ill keep you posted on any progress... bill
Joined: Aug 2012
Posts: 88
Likes: 1
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Had the no crank issue while shopping - figured it was an interlock. Walked home 6 miles and started reading the forums and found this issue. I went back to work on it after 3 hours and it started right up. Took it apart and the center solder posts were cracked. Repaired and restarted. Then the BAS/ESP light stayed on...rechecked cabling and back to the forum again. Found the suggestion of turning the steering wheel lock to lock and it worked. THIS IS A GREAT FORUM!!!!
Last edited by gp1200x; Sep 8, 2013 at 02:17 PM.
Joined: May 2011
Posts: 1
Likes: 0
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Well folks I am happy to announce that we now have a Loaner Relay Control Module (L-RCM) thanks to one of the Texas crew,
Having the L-RCM will allow forum members to get their cars back on the road quicker as now I can send them a repaired RCM at the same time they send me their bad RCM. Saving 2-3 days of shipping time. So instead of waiting about a week yer back on the road in just a few days.
Here how it will work (I'll post this in the first thread for easy reference):
Once you have narrowed down your problem to the RCM (No crank, all electronics work) notify me that you are ready to send your RCM to me. We will swap contact information and both ship the RCMs out. You receive the repaired RCM (with the "Me So Horny Mod") and I receive your bad RCM.
I will test/repair and test the "bad" RCM and it will become the next L-RCM waiting to help the next member.
Still asking at least $10 for this service so I don't get stuck paying postage! Hey. I'm nice but not THAT nice! Just ask PzziaGuy!
LGV-XFIRE
(big round of thanks for Jeff)!
(big round of thanks for Jeff)!
Having the L-RCM will allow forum members to get their cars back on the road quicker as now I can send them a repaired RCM at the same time they send me their bad RCM. Saving 2-3 days of shipping time. So instead of waiting about a week yer back on the road in just a few days.
Here how it will work (I'll post this in the first thread for easy reference):
Once you have narrowed down your problem to the RCM (No crank, all electronics work) notify me that you are ready to send your RCM to me. We will swap contact information and both ship the RCMs out. You receive the repaired RCM (with the "Me So Horny Mod") and I receive your bad RCM.
I will test/repair and test the "bad" RCM and it will become the next L-RCM waiting to help the next member.
Still asking at least $10 for this service so I don't get stuck paying postage! Hey. I'm nice but not THAT nice! Just ask PzziaGuy!
Hi Tighed1 ~ Do you still offer this service? I am new to the forum and am having lots of issues with the sticky starter and I believe the RCM after reading your posts. Is it OK to ask you to reply to me at a.knudsen00@gmail.com? Kindest Regards, Seraphia my silver-blue convertible
