[FLATOUTRACING]

Have a 2016 SS1. Have posted on here before. Have had quite a few slow crank, no start issues leaving me stranded several times over the past two years. Went through all the regular fixes including battery, ground straps, starter and eventually issues with fuel pumps (no fuel on the last two issues where it would crank but not turn over). Finally it was diagnosed as a faulty chassis contol module which was on back order for four months. Part number is 84084065. Had to be specifically coded by the dealer to my specific vin #. It fixed the issues but when I got the car back after it sat for 4 months, the suspension seems very stiff and bouncy, especially at the rear. I've raced in SCCA and Grand Am for years so stiff suspensions don't really bother me but it almost feels like the suspension bushings were replaced with spherical bearings usually found on race cars. When I hit bumps or expansion joints on the road there is very little absoroption almost like the bushings are badly worn. Even at low speed in my parking garage with ride is really bad (almost like a pogo stick). Makes very little difference in T, S or Track mode.

I am wondering if the tires may be flat spotted from sitting all that time and that during the cold weather here in DC, that the tires may have dropped a few pounds of pressure while it sat at the shop but I don't really get vibration through the steering wheels you usually get with flat spotted tires.

I was told by my shop that this particular chassis control module (which neccessitates taking the fuel tank out) is the module that sends a signal from the fuel pump in the tank to the second one on the engine and regulates fuel delivery and pressure.

Does this control module also in any way regulate suspension settings or control the chassis settings such as traction control, bump, rebound etc. My car does have the magnetic suspension.

Any ideas out there, anyone experience this. Thanks in advance.

[mRahmani]

I wonder if you have a seized shock. Does the suspension articulate normally if you jack it up?

The magride is controlled by a module in the trunk, underneath the carpet. It’s possible that there’s some communication between that module and the chassis module that isn’t taking place but I don’t know enough about it to say for sure.

[easttxss]

Had a coworker that had to replace the shocks on his CTS-V, his complaint was a rough ride.

[ShockingZ]

I know the CCM controls the NPP valves. Not sure what else. But I've heard you can buy HPT credits and read it out and then can make changes to the CCM on how it controls the NPP. Im sure there is more It controls. I think its two credits?

[Idlefury]

As mentioned above, it could be the shocks themselves. I recently had to replace the rear shocks in my 2016. They got so stiff, it felt like it had no suspension. Both shocks were leaking. Crawl underneath yours and take a look for signs of leakage. Rock Auto was the cheapest place I found for replacements but they're not cheap!

[Casper the friendly G]

Originally Posted by FLATOUTRACING

Have a 2016 SS1. Have posted on here before. Have had quite a few slow crank, no start issues leaving me stranded several times over the past two years. Went through all the regular fixes including battery, ground straps, starter and eventually issues with fuel pumps (no fuel on the last two issues where it would crank but not turn over). Finally it was diagnosed as a faulty chassis contol module which was on back order for four months. Part number is 84084065. Had to be specifically coded by the dealer to my specific vin #. It fixed the issues but when I got the car back after it sat for 4 months, the suspension seems very stiff and bouncy, especially at the rear. I've raced in SCCA and Grand Am for years so stiff suspensions don't really bother me but it almost feels like the suspension bushings were replaced with spherical bearings usually found on race cars. When I hit bumps or expansion joints on the road there is very little absoroption almost like the bushings are badly worn. Even at low speed in my parking garage with ride is really bad (almost like a pogo stick). Makes very little difference in T, S or Track mode.

I am wondering if the tires may be flat spotted from sitting all that time and that during the cold weather here in DC, that the tires may have dropped a few pounds of pressure while it sat at the shop but I don't really get vibration through the steering wheels you usually get with flat spotted tires.

I was told by my shop that this particular chassis control module (which neccessitates taking the fuel tank out) is the module that sends a signal from the fuel pump in the tank to the second one on the engine and regulates fuel delivery and pressure.

Does this control module also in any way regulate suspension settings or control the chassis settings such as traction control, bump, rebound etc. My car does have the magnetic suspension.

Any ideas out there, anyone experience this. Thanks in advance.

Do you have mag ride? I had a leaking rear shock and Mag ride became no adjustable and the whole rear tightened up. Speed bumps were hard. 1 shock was bad and dealer replaced both rear. Now working again and mag ride functioning.

[Texas1ss]

Originally Posted by FLATOUTRACING

Have a 2016 SS1. Have posted on here before. Have had quite a few slow crank, no start issues leaving me stranded several times over the past two years. Went through all the regular fixes including battery, ground straps, starter and eventually issues with fuel pumps (no fuel on the last two issues where it would crank but not turn over). Finally it was diagnosed as a faulty chassis contol module which was on back order for four months. Part number is 84084065. Had to be specifically coded by the dealer to my specific vin #. It fixed the issues but when I got the car back after it sat for 4 months, the suspension seems very stiff and bouncy, especially at the rear. I've raced in SCCA and Grand Am for years so stiff suspensions don't really bother me but it almost feels like the suspension bushings were replaced with spherical bearings usually found on race cars. When I hit bumps or expansion joints on the road there is very little absoroption almost like the bushings are badly worn. Even at low speed in my parking garage with ride is really bad (almost like a pogo stick). Makes very little difference in T, S or Track mode.

I am wondering if the tires may be flat spotted from sitting all that time and that during the cold weather here in DC, that the tires may have dropped a few pounds of pressure while it sat at the shop but I don't really get vibration through the steering wheels you usually get with flat spotted tires.

I was told by my shop that this particular chassis control module (which neccessitates taking the fuel tank out) is the module that sends a signal from the fuel pump in the tank to the second one on the engine and regulates fuel delivery and pressure.

Does this control module also in any way regulate suspension settings or control the chassis settings such as traction control, bump, rebound etc. My car does have the magnetic suspension.

Any ideas out there, anyone experience this. Thanks in advance.

This post gives me bad flashbacks on a backorder chassis control module I actually drove a 10 hour round trip to get because my dealer couldn't find it.
Same part number.

My OBD was popping off PO23F and PO69E, which was fuel pump codes. It was intermittent. They ended up changing the fuel pump and module, and it came back a month later. I was also having traction control lights on my dash and ABS, and when I tried to use the fob to lock my car the lights stayed on. Weird stuff.

Long story short, the module controls a lot more than I thought. In my case, once a dealership knew what they were doing mine was only a wiring issue to the module. 300 bucks problem solved. But it was a couple of months of pure bullshit and over 2k. I can relate.