[Proxis]

Hey everyone,

Hoping someone can help me brainstorm. I have a pesky suspension issue I'm chasing.

So, I've replaced both front control arms on both sides after a relatively minor angled collision that broke the passenger side front rear lower control arm and slightly bent the passenger front lower control arm.

I have 2016 Camaro 2SS with Magnetic Ride Control Suspension and about 55,000 miles


I replaced the following:

• Front Passenger Side Knuckle,
• Front Passenger Side wheel bearing/hub,
• Front Passenger & Driver Side rear and front control arms
• Sway Bar
• All brake pads and rotors
• All Tires
• Passenger Side Rim
  

The car drives like new now. However, the only remaining issue I have is there's a speed limiter to 85 mph.

I have a Cardaq plus that I used to scan the car using GDS2 and hooked up to a ProLogix Stable Battery Power Supply set at 14V. The fault codes that came up are all related to suspension (only visible on GDS btw, my dashboard doesn't show a CEL and the "Service Suspension" message only pops up briefly on startup). Lastly, also checked the data feed for the suspension control module and I have uploaded the reports here.

What I have done so far:

• Checked the pins of the connector on the suspension control module to see if the cable itself was receiving voltage
• The pin for the thick red cable (positive I'm guessing) was receiving 14volts
• The pin for the thick black wire (ground I'm guessing) read 0.00 \(\Omega \).
• Checked the individual sensors at the shocks and their wiring looks intact and good, no signs of damage in any of them.
• Checked the shocks themselves, they have no visible fluid seepage.

My questions are:

• Could the speed limiter be because of these faults?
• Why would all four corners be throwing up codes if the rear suspension has been completely untouched.
• Does a 0V battery voltage reading indicate that suspension control module is faulty if the cable itself is receiving power from the stable power supply?

[bishopts]

Without seeing it or a diagram. I would suspect a fuse. Or a ground

[bishopts]

here is the diagram, i would check the fuse

[bishopts]

here is the oem diagram

[cdb95z28]

That data is showing the FEA suspension control module, which is the ZLE's RPO suspension code. Your MagRide non 1LE suspension code is FE3 IIRC, along with F55 for the MagRide dampers.

[bishopts]

Originally Posted by cdb95z28

That data is showing the FEA suspension control module, which is the ZLE's RPO suspension code. Your MagRide non 1LE suspension code is FE3 IIRC, along with F55 for the MagRide dampers.

I dunno. I just looked up electronic suspension for an SS. My car has regular struts so it's harder for me to help here. I didn't find any other suspension options in the diagrams for SS cars.

[arpad_m]

Originally Posted by cdb95z28

That data is showing the FEA suspension control module, which is the ZLE's RPO suspension code. Your MagRide non 1LE suspension code is FE3 IIRC, along with F55 for the MagRide dampers.

He is showing the correct F55 MRC suspension control diagram.

The page in the service manual is titled "Electronic Suspension Control Schematics (Electronic Suspension Control (F55))", and there is no reason FEA would have these four shock absorber actuators when its Multimatic DSSV shocks aren't electronically variable units.

[cdb95z28]

Originally Posted by bishopts

I dunno. I just looked up electronic suspension for an SS. My car has regular struts so it's harder for me to help here. I didn't find any other suspension options in the diagrams for SS cars.

Originally Posted by arpad_m

He is showing the correct F55 MRC suspension control diagram.

The page in the service manual is titled "Electronic Suspension Control Schematics (Electronic Suspension Control (F55))", and there is no reason FEA would have these four shock absorber actuators when its Multimatic DSSV shocks aren't electronically variable units.

Sorry, I was quoting the info from the OP's post containing the GDS2 data.

[Proxis]

Appreciate you guys providing the wiring diagram. I ended up having my local Chevy service department diagnose it to confirm whether it is the module itself or a wire. It's been a couple days now and they haven't figured out what it is and actually ended up needing to reach out to GM tech line for a corrected wiring diagram because the one they had for my my car was wrong.

I bought a new module that's on its way just in case it does turn out that it's the module that's fried. I can flash the new module at home.

Once I receive a diagnosis and I repair it I'll update the thread for anybody that might run into the same issue.

[bishopts]

Originally Posted by Proxis

Appreciate you guys providing the wiring diagram. I ended up having my local Chevy service department diagnose it to confirm whether it is the module itself or a wire. It's been a couple days now and they haven't figured out what it is and actually ended up needing to reach out to GM tech line for a corrected wiring diagram because the one they had for my my car was wrong.

I bought a new module that's on its way just in case it does turn out that it's the module that's fried. I can flash the new module at home.

Once I receive a diagnosis and I repair it I'll update the thread for anybody that might run into the same issue.

All the good techs have got out of the business. The new ones have such a steep learning curve, it's hard for them to grasp everything necessary to diagnose properly.

Sometimes wiring diagrams have the wrong colors labled. Usually the pin configurations are right tho. A guy i taught electrical to was pretty good at tracking down faults in situations like that, he never knew it until i told him that he was colorblind. So i showed him how to find the wires only using the pin cavities.
It was funny, he was trying to wire an aftermarket radio up and couldn't get it to work. I looked at the wires and they were supposed to just be color matched. He had purple to grey, green to blue. I was like why did you wire it all dumb like this? Turns out he thought it was right. So yea we both learned he was color blind that day lol.

[Proxis]

Originally Posted by bishopts

All the good techs have got out of the business. The new ones have such a steep learning curve, it's hard for them to grasp everything necessary to diagnose properly.

Sometimes wiring diagrams have the wrong colors labled. Usually the pin configurations are right tho. A guy i taught electrical to was pretty good at tracking down faults in situations like that, he never knew it until i told him that he was colorblind. So i showed him how to find the wires only using the pin cavities.
It was funny, he was trying to wire an aftermarket radio up and couldn't get it to work. I looked at the wires and they were supposed to just be color matched. He had purple to grey, green to blue. I was like why did you wire it all dumb like this? Turns out he thought it was right. So yea we both learned he was color blind that day lol.

Quite the way to find out someone is colorblind hahaha bless their soul.

[Proxis]

Okay, so for anyone that might run into this -- my local "Authorized" Chevrolet service department confirmed to me that the suspension control module does need replacing.

Funny enough, to bishopts point, they were calling it the chassis control module for like 3 days, only on the last day they realized they were actually dealing with suspension control module (fyi, image below and located in the left of trunk floor, underneath the carpet and bolted right below the Bose amplifier).

Also, turns out GM discontinued the suspension control module -- I didn't ask if just the part number is being replaced or if it was full discontinuation. Either way, they were attempting to source and buy a suspension control module on eBay on my behalf, but for like $650. I didn't even bother to ask how much the install and flashing would've cost.

Luckily, I had already ordered one earlier this week from a reputable eBay seller and it was scheduled for delivery today. All at a cost of $70.

So, I am taking my car back and gonna get the module flashed this weekend. It is my first time ever flashing a module so wish me luck lol. I'll share the new suspension data feed from GDS2 after the install and (hopefully successful) flash.

[Proxis]

Okay, so for anyone that may run into this in the future. Here is the conclusion.

If you run check the SCM data display and your "SCM Battery Voltage" shows 0 V. That is definitely not normal, and as the posters above mentioned, it could be a damaged/corroded wire. But, it could also be a failed suspension control module. In my case, it was the module itself that was failed. And in hindsight I believe the biggest tell was that my SCM DTCs were on all four of my struts actuators -- which seems unlikely to be caused by just a wire. Would take multiple wires to be damaged/corroded.

Replacing it was easy. Flashing it was even easier. The hardest part in the entire flashing process was bringing my mesh WiFi router to my garage to have good internet signal.

This thread wasn't intended to be a tutorial so forgive me for the lack of pictures and details. However, it was a very very very easy fix. The flashing itself took less than 5 minutes. Swapping the modules took 10minutes at the most.

Total Cost

• $260 for diagnostic confirmation from my dealership (I didn't have time to chase wires)
• $70 for the SCM on eBay,
• $45 for the GM's techline connect.
• $64 3-Day GDS2 Subscription (although there are forums going over how to get GDS2 with a lifetime subscription for free/lower costs. Proceed at your own risk there)

Equipment/Software Needed

• Stable Battery Power Supply (highly recommend it as I've read that voltage drops could cause the flashing to fail), I used a Pro-Logix/Clove Automotive PL6800 and set my voltage supply to 14 volts
• J2534 Pass-Thru Device, I used a CarDaq Plus 3 but a Mongoose would have been cheaper and every bit as functional. Just make sure to download the proper drivers for your chosen j2534 device.
• Windows Laptop (Windows 10 was the recommended OS but my laptop had Windows 11)
• GM's GDS2
• GM/AC Delco Techline Connect
• 10mm and 7mm sockets

After reflashing the module clear your DTC's. Lastly, you may need to recalibrate/set your your ride height. Do so on a flat surface like in your garage. You can do this on GDS 2.

Fixing this was literally the easiest thing I have ever done to my car, the diagnosis was the only time sink.

This fixed my issue with the car being automatically limited to 85 mph and also fixed the bouncy/unusually soft (but not bottoming out) suspension issue I was having.