No communication with any modules
Thread Starter
Newbie
Joined: Apr 2019
Posts: 6
Likes: 0
2008 C300
No communication with any modules
2008 C300 4Matic. Car came in for a misfire. Attempted to scan modules, unable to connect to any module. The scan tool does light up when plugged in. Customer also stated that they had it at the dealer, and they were unable to remedy the problem. All help would be appreciated. Thank you.
Super Member
Joined: Nov 2016
Posts: 680
Likes: 152
2008 C350 Sport 4Matic Swap
take the driver side carpet out and check the SAM box, I've seen this problem once and all the wires/modules were corroded. Very bad design putting so much electronics right under the driver's feet when water is guaranteed to get in. Weather tech mats are a must if you live in areas where you get snow and personally, I took it all apart and coated everything with dielectric grease, including some extra covers to prevent this issue altogether. Good luck.
Super Member
Joined: Nov 2016
Posts: 680
Likes: 152
2008 C350 Sport 4Matic Swap
Thread Starter
Newbie
Joined: Apr 2019
Posts: 6
Likes: 0
2008 C300
I checked the wires earlier. No green crusties. I also removed the connections, didn't find any corrosion on them. There was a very small amount of water on the floor. The carpet and foam was not damp.
Super Member
Joined: Nov 2016
Posts: 680
Likes: 152
2008 C350 Sport 4Matic Swap
What exactly isn't connecting with the scan tool? And what kind of scan tool is it? Are you able to connect to any module or is it just the ECM? If you are not able to connect with anything, I would start by checking a wiring diagram for the OBD2 port and check if each wire is doing what it should.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Newbie
Joined: Apr 2019
Posts: 6
Likes: 0
2008 C300
Super Member
Joined: Jun 2016
Posts: 562
Likes: 75
Mercedes w204 4matic sport
You have a bad module or short to ground imo. Unplug one module at a time and see if the scan tool reads. If no, reconnect that module and go to the next one. Start with the easy ones. If you disconnect a module and then have communication that module is bad and is the cause of no communication. If this approach don’t work you need to inspect the cars wiring.
Thread Starter
Newbie
Joined: Apr 2019
Posts: 6
Likes: 0
2008 C300
You have a bad module or short to ground imo. Unplug one module at a time and see if the scan tool reads. If no, reconnect that module and go to the next one. Start with the easy ones. If you disconnect a module and then have communication that module is bad and is the cause of no communication. If this approach don’t work you need to inspect the cars wiring.
