How to Repair Relay Control Module (RCM) - (Mystery no Start)
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re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
not to cloud up this thread but I've read that the p0140 code could be caused by this RCM trouble... how likely is it that this is the cause before i go digging for my RCM? specifically, I was never really good about coloring in the lines so I don't think my soldering skills will be up to par either and I may need to send mine to tighed1
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I have a 2004 crossfire and she died on me today. I have read a lot of different threads and want to know which is my problem. When I turn the key I hear a quick buzz sound all off my lights come on my temperature gauge doesn't move, I don't get a click click click sound and the fan comes on and stays on. Someone help!!!!!
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
My wife's 2004 Crossfire had this issue around May 9th, 2012. I switched the crankshaft position sensor and it continued to stall. I read a thread about soldering the RCM and followed directions. Viola! it worked just fine. Fast forward 7 days later and it started to stall again. So I ordered a brand new RCM from my local MB dealer and it was at my home the next day. I installed the new RCM and it started like a champ. I decided to let it run and sure enough it stalled. So I took it to a mechanic and told him I installed a new CPS and RCM. After 1 week he called and told me that he fixed the problem. He had to replace my BWD/Intermotor CPS (purchased at Advance Auto) with a Bosch CPS and then RELEARN it. The car hasnt stalled and it runs great.
Last edited by glenn8612; 05-29-2012 at 09:36 AM.
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Running the Advanced Auto version right now (must have situation) with a Bosch riding in the net behind the seat. So far at least 30 days into it and doing fine. Actually I had been getting the 02 sensor code-cel every couple of weeks and for some reason it is on vacation now too. Don't know about the "relearn" part.. dropped mine in the hole..hooked up wires.. and drove 35 miles right out of the box..
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
about $65 Advanced Auto.. lifetime warranty.. we'll see...lol
RCM .. Relay control module.. search through "mystery no start" (this thread).. check the solder joints..
Last edited by Mrmiata; 06-01-2012 at 12:17 PM.
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re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Yea, for a CPS you really want a Bosch part. I got mine from Autohaus in Arizona for just under $60 with shipping. I have it in the trunk, waiting for it to be needed.
The RCM resoldering is not hard, for those who can solder. My RCM looked awful when I got the car, but it never actually failed on me. I pulled it and resoldered it anyway. Tighd1 also has indicated that he's seen some pitted/dirty relay contacts as well, so cleaning them with a relay burnishing tool (if you can FIND one) is a good idea, too. But most of the time, it's broken solder joints.
Either the CPS or RCM can cause the car to not start OR to stall OR to crank but not start.
And, of course, old batteries (even when they test good) can cause all sorts of odd problems.
In any event, the common problems are (and I"m probably leaving some out):
RCM solder joints bad
CPS gone bad
RCM Relay contacts pitted/dirty
Old batteries
Corroded terminals on the battery and/or on the ground lug at the opposite end of the battery ground cable.
I think I have heard of one or two CAMSHAFT position sensors going bad, but that is really rare.
Bad fuel pump (although it's usually the fuel pump relay in the RCM)
ANY of these can cause engine stalling/starting problems. A bad CPS usually throws a code and lights the engine light, but not always.
The RCM resoldering is not hard, for those who can solder. My RCM looked awful when I got the car, but it never actually failed on me. I pulled it and resoldered it anyway. Tighd1 also has indicated that he's seen some pitted/dirty relay contacts as well, so cleaning them with a relay burnishing tool (if you can FIND one) is a good idea, too. But most of the time, it's broken solder joints.
Either the CPS or RCM can cause the car to not start OR to stall OR to crank but not start.
And, of course, old batteries (even when they test good) can cause all sorts of odd problems.
In any event, the common problems are (and I"m probably leaving some out):
RCM solder joints bad
CPS gone bad
RCM Relay contacts pitted/dirty
Old batteries
Corroded terminals on the battery and/or on the ground lug at the opposite end of the battery ground cable.
I think I have heard of one or two CAMSHAFT position sensors going bad, but that is really rare.
Bad fuel pump (although it's usually the fuel pump relay in the RCM)
ANY of these can cause engine stalling/starting problems. A bad CPS usually throws a code and lights the engine light, but not always.
My problem is this. My fan ONLY comes on when then engine is to hot and my babe cuts off. Is that the RCM. If so we fixed it. Maybe I need to.send it out
QUOTE=pizzaguy;676145]Yea, for a CPS you really want a Bosch part. I got mine from Autohaus in Arizona for just under $60 with shipping. I have it in the trunk, waiting for it to be needed.
The RCM resoldering is not hard, for those who can solder. My RCM looked awful when I got the car, but it never actually failed on me. I pulled it and resoldered it anyway. Tighd1 also has indicated that he's seen some pitted/dirty relay contacts as well, so cleaning them with a relay burnishing tool (if you can FIND one) is a good idea, too. But most of the time, it's broken solder joints.
Either the CPS or RCM can cause the car to not start OR to stall OR to crank but not start.
And, of course, old batteries (even when they test good) can cause all sorts of odd problems.
In any event, the common problems are (and I"m probably leaving some out):
RCM solder joints bad
CPS gone bad
RCM Relay contacts pitted/dirty
Old batteries
Corroded terminals on the battery and/or on the ground lug at the opposite end of the battery ground cable.
I think I have heard of one or two CAMSHAFT position sensors going bad, but that is really rare.
Bad fuel pump (although it's usually the fuel pump relay in the RCM)
ANY of these can cause engine stalling/starting problems. A bad CPS usually throws a code and lights the engine light, but not always.
[/QUOTE]
QUOTE=pizzaguy;676145]Yea, for a CPS you really want a Bosch part. I got mine from Autohaus in Arizona for just under $60 with shipping. I have it in the trunk, waiting for it to be needed.
The RCM resoldering is not hard, for those who can solder. My RCM looked awful when I got the car, but it never actually failed on me. I pulled it and resoldered it anyway. Tighd1 also has indicated that he's seen some pitted/dirty relay contacts as well, so cleaning them with a relay burnishing tool (if you can FIND one) is a good idea, too. But most of the time, it's broken solder joints.
Either the CPS or RCM can cause the car to not start OR to stall OR to crank but not start.
And, of course, old batteries (even when they test good) can cause all sorts of odd problems.
In any event, the common problems are (and I"m probably leaving some out):
RCM solder joints bad
CPS gone bad
RCM Relay contacts pitted/dirty
Old batteries
Corroded terminals on the battery and/or on the ground lug at the opposite end of the battery ground cable.
I think I have heard of one or two CAMSHAFT position sensors going bad, but that is really rare.
Bad fuel pump (although it's usually the fuel pump relay in the RCM)
ANY of these can cause engine stalling/starting problems. A bad CPS usually throws a code and lights the engine light, but not always.
[/QUOTE]
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re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
All of the cars come from the factory with a fan-turn on of well above 200 degrees F. So, it is normal for the temp needle to go a bit above halfway before the fan comes on (well after the thermostat has opened). I had my fan turn on set down 10 degrees C (which is 18F) and the needle NEVER makes it to the halfway point now.
Anyway, if the fan is REALLY not starting until the engine cant even run any more, it's time to stop drviing the car and get this taken care of!
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re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I can't see it being the RCM. There is nothing on the RCM that has anything to do with cooling the engine.
The PTCM (Power Train Control Module) receives informatoin on engine temperature from a sensor in the engine and commands the Fan Control module to run the fan in response to engine temperature. It SOUNDS like the sensor is not accurately reporting temperature to the PTCM.
Here is a test: Start the car when it's cold, the fan should NOT run. Now, turn the A/C on, the fan MUST run at slow speed. If it doesn't, I'd suspect the Fan Control Module, Power Train Control Module or Body Control Module.
Does your yellow coolant light ever come on? (Looks like a radiator, in the left hand gropu of lights, left of the speedometer).
The PTCM (Power Train Control Module) receives informatoin on engine temperature from a sensor in the engine and commands the Fan Control module to run the fan in response to engine temperature. It SOUNDS like the sensor is not accurately reporting temperature to the PTCM.
Here is a test: Start the car when it's cold, the fan should NOT run. Now, turn the A/C on, the fan MUST run at slow speed. If it doesn't, I'd suspect the Fan Control Module, Power Train Control Module or Body Control Module.
Does your yellow coolant light ever come on? (Looks like a radiator, in the left hand gropu of lights, left of the speedometer).
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Running the Advanced Auto version right now (must have situation) with a Bosch riding in the net behind the seat. So far at least 30 days into it and doing fine. Actually I had been getting the 02 sensor code-cel every couple of weeks and for some reason it is on vacation now too. Don't know about the "relearn" part.. dropped mine in the hole..hooked up wires.. and drove 35 miles right out of the box..
I guess I had bad luck because I switched the CPS in 20 minutes and it cost $60. The mechanic switched it and it cost $296. Oh, cant forget about the "relearn" process. LOL
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re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Picked up a soldering kit today, never attempted to solder before so let's hope for the best. Its only 25W though, will that be an issue? Also, I'm assuming that I am re-soldering just the bumps (which I'm guessing are the actual "connectors") in the indicated corner of the RCM and not actually trying to connect them to each other, correct? Lastly, does anyone have a time estimate on this? The kit came with lead-free solder which I've seen might take a bit more heat, but I'm hoping to get everything done, connected again and back on the road in under 2 hours... possible?