[Denmanman4]

Hey everyone. I have been looking through the threads and also ran a search in here but couldn't' find anything troubleshooting related to my issue. I'm currently over in Germany also so simply bringing it to a dealership to resolve my issue isn't really an option.

Long story short... Before I shipped my car over here the MRC seemed to work as intended on all 4 corners and after it arrived I can feel every bump that shoots up your spine and makes you cringe. It seems like all 4 corners are not working at all. It appears as though when going through the MRC settings that no adjustments are made when switching the mode.

I've read that leaking struts is a sign of them being bad but it's mostly wetness and doesn't seem to be too excessive either. (Class I leak for the military folks). I've seen a few peoples pictures of blown struts which looks like globs of grease wiped on them and mine do not appear like that.

My troubleshooting background leads me to believe it is the MRC Suspension Control Module since adjustments cannot be made and all 4 corners are not working. Problem with this is that I see that it requires programming and calibration from the dealership service department when you replace it.

Has anyone replaced this before and is there a true way to test it's functionality before replacing it?

[Ventmaster]

I know car makers put "spacers" in the shocks of cars to minimize movement and maintain ride height while shipping new cars to dealers. Sometimes they forget to take them out.
Any chance they are on your car for the ride to Germany?

[Msquared]

If the spacers aren't in there (per Ventmaster's suggestion), then the fact that you are feeling every bump so intensely probably means the shocks are too stiff, not that they aren't doing anything. That generally means there is more voltage going through the magnetorehological fluid, thereby increasing its viscosity a lot. This could be the result of your module getting a bad signal somewhere and thinking you want it in Track mode all the time. Does your dash indicate that it's in Track mode? Do the damper rates feel any different if you cycle through the modes?

But even in Track mode, there is modulation of the fluid viscosity (voltage). If the dampers are always feeling like they're locked up solid, maybe the module has just defaulted to full voltage all the time. I don't know if there's a fault where the module can actually do that or not. Are you getting any DTCs? Looking in the service manual, there is a big section on troubleshooting a bunch of different codes. It's dozens of pages, but if you were able to pull a code then maybe I can relay what it says to you.

However, my guess is that the shippers put spacers in there for the trip and forgot to remove them.

[Denmanman4]

Originally Posted by Msquared

If the spacers aren't in there (per Ventmaster's suggestion), then the fact that you are feeling every bump so intensely probably means the shocks are too stiff, not that they aren't doing anything. That generally means there is more voltage going through the magnetorehological fluid, thereby increasing its viscosity a lot. This could be the result of your module getting a bad signal somewhere and thinking you want it in Track mode all the time. Does your dash indicate that it's in Track mode? Do the damper rates feel any different if you cycle through the modes?

But even in Track mode, there is modulation of the fluid viscosity (voltage). If the dampers are always feeling like they're locked up solid, maybe the module has just defaulted to full voltage all the time. I don't know if there's a fault where the module can actually do that or not. Are you getting any DTCs? Looking in the service manual, there is a big section on troubleshooting a bunch of different codes. It's dozens of pages, but if you were able to pull a code then maybe I can relay what it says to you.

However, my guess is that the shippers put spacers in there for the trip and forgot to remove them.

there are no spacers and not DTC's......

[Msquared]

Very strange. To recap, then, if it were the shocks failing, they car would wallow and ride too soft with no control of oscillations. The springs will still suspend the car: the shocks have no spring function, so if they fail it's not as if the car settles onto its bump stops like a failed air-ride suspension. Something is causing all four (we think) of your shocks to get max voltage and therefore ride at full-stiff damping rates all the time. I've never heard of this problem in any car with these shocks before. I think it would be worth disconnecting the battery for a few minutes and see if that "resets" things. I don't know what else to suggest at this point!

[Denmanman4]

Originally Posted by Msquared

Very strange. To recap, then, if it were the shocks failing, they car would wallow and ride too soft with no control of oscillations. The springs will still suspend the car: the shocks have no spring function, so if they fail it's not as if the car settles onto its bump stops like a failed air-ride suspension. Something is causing all four (we think) of your shocks to get max voltage and therefore ride at full-stiff damping rates all the time. I've never heard of this problem in any car with these shocks before. I think it would be worth disconnecting the battery for a few minutes and see if that "resets" things. I don't know what else to suggest at this point!

Exactly. It is weird that it’s acting this way with no DTC’s populating. Is there a fuse associated with MRC that you know of as well? And I think it may be worth trying a full system reset with the battery disconnect. I can’t see it making the issue worse.

[Msquared]

Below is a diagram from page 10789 of the Factory Service Manual. That's the first page of a whole section on the F55 (MRC) damping system. Might be worth tracking down the G303 ground to see if it got cut or disconnected somehow. Still, I would think even if the MRC module lost all power, the dampers would default to little or no damping rather than locked up solid. I sent you a link to a document that might be helpful, but it will take you some time to sift through.

[Denmanman4]

Much appreciated. I'm very accustomed to schematics so this is going to be a fun troubleshooting experience. I'll be sure to share the outcome (hopefully a positive) after I hopefully get some time this weekend, so we can all learn from this.

[Scargoes]

How did the vehicle get shipped? If by sea, I'd check electrical connectors for corrosion. I'd also check for damaged/bent struts or other suspension parts/hardware from the tie down process.

[Denmanman4]

Originally Posted by Scargoes

How did the vehicle get shipped? If by sea, I'd check electrical connectors for corrosion. I'd also check for damaged/bent struts or other suspension parts/hardware from the tie down process.

Yes it was by Sea, less than 2 weeks on the boat. I had it on a lift to ensure there was no damages or new leaks from the process and it was all good. No visibile damages from tie down points, wear of material from straps or anything. (6 years ago when I shipped it here they cracked 6 out of 8 ringlands on my pistons) This time I set redline at 3k before shipping it to ensure they didn't blow it up on me again.