Bought a basket case to bring back to life. It is currently in a no crank state. My first thought was the RCM as I have dealt with that before on Mercedes but looks like the solder repair was already done and has continuity. I then went to pull any ODBII codes as a next step and my scanner is not detecting any protocols. Looking for ideas on how or where to test the ECU or other ideas why ODBII is not being detected.
I know this isn't much information to go on. Is there a post with wiring diagrams available as my searches so far haven't revealed one

2006 crossfire convertible manual 66k

Thanks for any relevant ideas or help.

 

The relays go bad in the RCM also.

 

Will that cause the ODBII to not connect to ECU? Not my understanding of how things work, but I am wrong all the time.
Probably shipping the RCM to be rebuilt anyways

 

You must have a correct reader and enter it as a 2004 Mercede4s SLK 320 since that is what it is.

 

Thanks, no joy on OBD. PO took a weedeater to the wiring harness which is why I am looking for a wiring diagram

 

Yes, If the Engine Control Relay is not closing, the ECU is not powered up.
You are wasting your time without the service manual. And using the search function here is an asinine waste of time, as you have already discovered.

Go to Google: Input this "Chrysler Crossfire Service manual", scroll past all the vapid, worthless responses until you fine a link to this forum.
That's how I search this forum, works very well.

Then, bookmark this link, the fourth response under "crossfireforum" in the google results:
​​​​​​Crossfire Documentation Collection - CrossfireForum - The Chrysler Crossfire and SRT6 Resource

 

Thanks, I know this has all been asked before, but trying to get this running as a Christmas present for my father. Has been his dream car for the last while so appreciate the patience.

 

RCM has been sent for repair, in the meantime, can someone tell me how many wires are supposed to be going to this plug in the middle with one wire. I believe from looking at diagrams it is the traction control relay and think one of the two wires from the bottom photo should be going to it?

MIddle plug

wire mess

 

Pin 4 is Red/Yellow and feeds the Traction Control Module
Pin 5 is Red/Dark Green and feeds the automatic shift lever assembly and the automatic transmission control module. (So you have no wire there.)

Wow, that car's wiring looks like someone took it to a stereo install shop that hires pot smoking dropouts.

 

I said it looks like they used a weedeater to repair thanks it is a manual so no wire would make sense. I may need to come look at your wiring harness pizza guy for some reference material... Acording to the vehicle history it was from Wylie so more likely it was meth smoking radio shop

 

Any idea what the two red and yellow wires coming up from the main body harness are? Wiring diagrams have been a while for me so looking in service manual but slow

 

Are you 100% sure the main wiring harness for a manual vs auto are different? Many times the harness is the same, but the modules hooked up to it are different (resulting in wires that are not used if not supported within the modules attached to them). During assembly, other 'sub harnesses' are further hooked to specific models, but common harnesses within vehicles are still used (to cut down the number of part numbers and stocked parts). Sorry if this tidbit isn't helpful, but hope you get this issue solved soonest (especially since someone has been cutting into wires already).


.

 

They had to re-use some color combos, so it can be hard to determine. Red/Yellow in every case I have found, is switched 12 volts except when its SCI transmit.

For example:
A/C heater controller: Pin 1 is Rd/YL fused B+
Body Control Module: C4 pin 44 is Rd/YL fused B+
Brake Lamp Switch: Pin 2 is Rd/YL Traction System 12V output (That may be one of them, in facth its AWG no 12).
Controller ABS pin 4 - comes from the RCM's Traction Control relay output (the wire that IS connected in our cars).
Console Switch Group pin 6 - FUsed B+
Coolant Pump (SRTs) pin 1 - FUsed B+
Coolant Circulation Valve (SRTs) a number 20 wire on pin 2 and a number 18 wire also on pin 2 - Fused B+
Heated Seat Module Pin 4 - Fused B+
Instrument Cluster pin 11A - Fused B+
Key-in Ignition switch Pin 2 - Fused B+
C200 - Pin 6 has two Rd/YL wires, both at pin 6 - SCI TX

The list goes on, start on page 8W-80 "Connector Pinouts", wire size is listed, which may help you narrow it down. I suspect you may be looking at wires pulled from the harness that were in there either for an automatic or an SRT. Remember, someone got in there and messed around. I see no loose Rd/Yel wires in my SE.

Try going thru the connector pinouts for connectors ONLY in the RCM/ECU box. See if any wires are missing from connectors, if not, then you KNOW they are unused wires some asshat pulled from the harness and played with.


Got a headache yet?

 

THey are not different. Hell, even our Base/Limiteds have not only the wiring for the SRT's coolant pump, we even have the coolant pump relay on the pulse module.

He's gotta be chasing wires pulled from the harness by someone - who knows what they were doing, but IN CASE they pulled a wire or two from a connector, I suggested he go in and verify that all the Red/Yellow wires that are supposed to be in the connectors in there, are actually connected. If they are, then he's chasing a wiring ghost and can move on.

 

I think it is the secondary horn and or alarm siren as it is sitting in the trunk and wire codes look the same upon quick inspection. I think somebody probably cut it during one of its I would assume many towing sessions..

I wonder about that on Mercedes I have seen them both with and without all the connectors required. Sprinter van - no additional as each harness was custom built. No idea on these cars yet. Although I assume it was as you describe with things just left unplugged. I hope that is the case if I find heated or powered seats to swap in.

 

I would urge you to make sure all Red/Yellow wires that SHOULD be in the various connectors in the RCM box are actually connected. Between looking them up in the back of hte manual and checking connectors, you'd have this done in an hour. Red/Yel does SO MUCH in the car that it could be alarm wiring, but it can easily be evidence of what some dull-witted person did to get the 'no crank' fixed, doing damage in the process. I've spent 30 years troubleshooting electronics, assuming is, at this point, a potential time waster.

There is a reason some of us can fix electronic issues, and a lot of it has to do with our knowledge of the wiring/electronics, but also our dedication to logical processes. "OH, its probably just this....." is not how you get to the bottom of unknown troubles. We do not move past something until we have eliminated it. If you proceed on this assumption, keep in the back of your mind that you never proved this.

 

Oh I will prove everything, just starting with the most likely and working backwards to the harder scenarios. I was assuming the towing, not the infinite wisdom of who hacked this harness. ,
Thanks for all the help and advice. Keep it coming!

 

During your tracing of the wiring to the RCM pins (since I have no idea how many are loose/weed eaten), you can use the wiring diagram in pages 8W - 10 - 21 & 22 (mine is the 2008 service manual), you can get the pages from your downloaded service manual, check page 8W - 10 - 1 lower right column under Relay Control Module in case your page numbers are different (since I have the 3-volume book set). Lets hope the color code/wire sizes are correct in your vehicle. Since they seem to have been cut up, might be a good idea to check all 5 connectors (each numbered pin/wire). Good luck!


.

 

I don't think my last post went through,

Car is now at a crank no start state after having the RCM repaired due to this wonderful forum. I am not hearing the fuel pump so will test fuel pressure first. Is there a recommended fuel pump brand or manufacturer as it appears everything is aftermarket now.

Progress!

 

Pierburg is what Mercedes used. Others will say aftermarket is ok.