1st post, new member. '04, owned for 3 years, 120K miles. Have not seen an inquiry on this subject, but could not look through all the 100's of threads there seem to be on the dozen or so pages. Check Engine light has been coming on for a few days, then going off for a few days. No other dash indications as to what might be causing it. Had it checked at a local small garage (not dealership), it was diagnosed as a brownish color change on a wire connected to the Relay Module, so new Module installed. A few days later, light comes on again. And since, off and on as before replacement part. All instrumentation on the dash remain functional, no other lights, no engine heating. I was advised to seek more help from a dealership. I am so not mechanical, need advise on trusting a dealership with diagnosing or if another small garage might be useful...another opinion without breaking the bank. Many thanks!

 

Have you checked it for codes when it's on?

 

You are probably going to need a dealer to diagnose this problem. I'm guessing O2 sensor, but that's just a WAG. Dealership will be able to monitor running parameters while most independent shops can't.

 

I monitor my OBDII port with an Ultragauge. I would NEVER advise someone to go to a dealer with a Crossfire, unless they can find a Mercedes dealer that will look at it.
What makes you think a check engine light is an automatic trip to the dealer? That is the LAST place you go - and after you have been around here a while, you will know why!


JJ- get yourself an Ultragauge ($80) and plug it in and wait, or, the next time it acts up, take it to AutoZone or Advance Auto and have the code(s) read - then come back here and we'll see what we can do to help.

 

I suppose if you have a way to scan dynamic engine characteristics such as HGO, on/off states, live maf, coolan temp etc then a dealer isn't needed. Most folks don't have access to interrogate live data from mercedes computers. You are right in that the dealer should be last resort but I try to shy away from just throwing parts at something and hoping to fix it. When o2 sensors start failing they usually throw codes that are non specific in many cases.What are you using to map all the live data from your crossfire, I want one but don't want to spend 3k on a used analyzer. Are the cell phone apps sophisticated enough to perform high level diagnostics now?

BTW, I have multilple OBDII scanners and a couple can-bus scanners, problem with the can-bus scanners is they are for VW's. I can read codes as well as anyone but interpreting the codes without live data can get expensive.

 

All the dealers do is throw parts at problems - that is my point. WE can throw parts at our cars cheaper than the dealer.

The ability to capture live data from the Ultragauge isn't what Rudy and his laptop can do - but I can watch MOST parameters live.

The point of my post was to strongly DIScourage anyone from taking the car to a dealer. And if you stick around and read posts from people who have already been to the dealers several times - and see the LITERALLY THOUSANDS of dollars it often runs into, you will see why I jumped on that.

That is NOT to say that going someone like Buckhead Imports is a bad idea - I've been down there myself and probably SAVED money by seeing them. But taking a Mercedes to a Chrysler dealer will not turn out well.

 

And Iv'e got to tell you - NEVER have I heard of a Chrysler dealer going so far as to read live data.
Again, stick around and read some of the horror stories that show up here.

It will truly sicken you.

 

I think we are basically in agreement but not everyone has the capability to repair cars themselves. It is tough to ask a novice to first diagnose, then replace-repair a problem with a vehicle if they don't even have a rudimentary understanding of what they are attempting. A trip to a Mercedes dealership may be cost effective for someone likethat.
What are you using that gives you live data as I will get one for myself.
The VW can-bus scanners that I have do all systems, air-bags, theft, HVAC etc as well as plotting, graphing, storing live data paramaeters. They cost less than $100 and do everything a stealership can do. I don't know of anything like this for our crossfires at that low of a cost. If they are out there let me know where I can get one, or the software for my laptop along with any special cable needed for the mercedes application.
Thanks

I just looked at the Ultragauge website. It does appear that most all the live parameters you would need for troubleshooting are available. I will probably order one if I can't find something more comprehensive at a reasonable price.

 

A lot of MB dealers won't touch our cars - or so they say. But there ARE a lot of "mom and pop" shops that work on MBs and THOSE are usually a good bet. Buckhead Imports in Atlanta being REALLY good, to the point they build and do major mods to our cars! They did my -10c fan mod for $50.

I have a local shop that four brothers own who do exotics as well as MB, BMWs and a lot of 'standard' stuff for things like brakes or easier stuff I don't want to do.

I swear by my Ultragauge! But it is not as extensive as what Rudy is doing with his laptop - you'd have to ask Rudy or one of the 'modders' on here what to buy - but you are right - it won't be $100.

I am not sure I will ever have a car without at least SOMETHING like the Ultragauge - for under $100 it is an awesome tool AND toy. If I lay my hands on a second crossfire, I will order an oil pressure gauge and Ultragauge as soon as I drive the car home. I'll then head for Buckhead and get the fan set down right away.

PM rcompart, bigkid, thirteendog, or amx1397 for answers about what is available ! (There are others on here, but those guys I KNOW will have answers for you.)

 

Exceptional comments/advise re. 'stealerships' ! I was SO not wanting to go that route! Also thanking the gent who realized I am, without a doubt, a novice at car mechanics...likely a gender problem. I have owned 4 MB's and had access to a wonderful private garage for many years, sadly it closed. And a note, I now reside about 60 miles from a major city. Will try the route of local auto parts places for a start as recommended. Also have a rural local guy with a small shop that has an Utragauge (now that I know what it's called) who said he could diagnose fairly straightforward problems, but explained there are many problems that 'hide', for lack of a better word. It may take a couple days but will report back. Very glad I chose this route first. Thanks!

"JJ- get yourself an Ultragauge ($80) and plug it in and wait, or, the next time it acts up, take it to AutoZone or Advance Auto and have the code(s) read - then come back here and we'll see what we can do to help."

 

I may be wrong but it is my understanding that if the CEL has come on at some point then a code has been set and is readable with the ultragauge or an OB11 reader. If the light goes out it means that the system has been checked 'x' number of times since the fault was detected and no fault has been found, when it comes on again either the fault has re-occurred or a new fault has been found. As the light goes on and off I suspect it is the same fault that is occurring and fixing itself somehow. Read the code and that will be a good start to the final solution to the problem.

How a brownish tinge to the insulation on a wire can be diagnosed as the fault is beyond me, this guy must throw chicken bones against a wall to interpret auto problems. Stay clear of this moron, he has cost you enough. I hope you have the old RCM he replaced as there was most likely nothing wrong with it and you may need it one day as a spare, he will probably sell it if he still has it.

 

Sounds like just a little more training.. and he could get a job with Chrysler!

 

The UltraGuage is currently at $60 ( with the rebate ), and you don't take it anywhere to have it read, you read the P codes yourself.

 

And then come back here where you can search that code and / or get some help and advice on what to do from there..!

 

Maybe he observed the wire insulation discoloring due to heat?