Background info:

1. 2015 M7 Z06 (I ordered in 2014 and have had since mid December 2014)
2. mods include ported throttle body, CAI, Borla X pipe and axle back, and DSC shock controller
3. approx 40,000 Miles

The last few times ive driven this car I’ve gotten a “service suspension system” message. After researching and reading on here, I chalked it up to bad connection at the DSC controller, knowing I’d eventually get around to pulling it out, and reinstalling it to make sure it’s seated well with the harness. Keep in mind, the warning has been intermittent.

This morning I drove this car for work, knowing I’d be on a long windy stretch, perfect for a spirited drive. Wouldn’t you know it, got the same message in the DIC. Then, while driving, the DIC said “speed limited to 85 mph” any time I got close to 80. I figured it was the computer somehow limiting my speed in case there really was a suspension issue.

Decided I’d open up the fender and uninstall/reinstall the DSC when I got home, so I did. To my surprise, the car suddenly wouldn’t start at all. All I got was the “press clutch to start car” message on the DIC. I fidgeted with fuses, uninstalled and reinstalled the DSC controller several times, even swapped out the clutch pedal switch (it was cheap and actually in stock locally). Still nothing. Not even a clicking sound at the starter. Battery said 80% at this point.

I had given up all hope, thinking I’d better button her up so tomorrow I can roll her about twenty feet forward where’d she’d be over my pit, so I could start checking for power at the starter. I’m not sure why, but on a whim I thought I’d try the stock shock controller. Plugged it back in, and whatdya know, she started right up. It’s the damn-dest thing I’ve ever seen, a shock controller keeping the ignition from cranking the engine...or was this just a weird coincidence? I’m going to check for codes, but also curious if anyone else has had similar shock controller with “no start” issues?

 

The DSC controller broke the high speed GMLAN. Without the GMLAN, no go.

 

What is this GMLAN? Any idea why it wouldn’t work with the dsc reinstalled, but did when I reinstalled the stock controller?

 

Many of the modules in the car communicate on this bus. Assuming that there are no bent pins on the DSC module, then the DSC module has failed.

 

Thanks. No bent pins that I could tell. Glad I kept the original module. I had no idea the shock controller could keep the car from even starting.

 

Google is your friend:

General Motors Local Area Network (GMLAN) is an application- and transport-layer protocol using Controller Area Network for lower layer services.

https://en.wikipedia.org/wiki/Genera...l_Area_Network

 

let us know how this gets solved, considering buying a DSC controller and I'm curious what's the problem and how they help you fix it...

 

Contact DSC and tell them what happened. They will probably have you send the controller back to them so they can check it out. Most likely failure point are the connector pins on both the car side and the controller side. Connections are always the most likely failure points when it comes to electronic failures. If the problem was with the car's side of the connection after a while you might see the problem crop up with the stock controller. Connection problems include contacts that have lost their spring tension and no longer make a reliable contact with the mating part, dirty contacts, pushed in pins that don't fully interface with the mating part or bent pins that are shorting with another pin.

Bill