550 shock actuators

There are dozens of posts on this subject in the 456/550/575M forum. Posting there will get you much better response. There is a list of what can cause a suspension lamp in the workshop manual.


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How close are you to a Ferrari technician with an SD1 tool? Often you can waste time pulling the car to pieces when the problem can be identified in a few minutes with the SD1.

The manual says the faults are stored permanently in the suspension ECU, but that doesn't mean the fault light won't go out if you fix the problem. Just be careful when messing with the accelerometer wiring. You may need an SD1 tool to extinguish the suspension light after disturbing these (even if you replaced the very expensive accelerometer).
Be careful when refitting the actuators. Sometimes they look like they are seated properly, but aren't. Double check.

The V12's seem to suffer from twisting harnesses on the shock actuator. Part of the assembly rotates when it shouldn't. Look for twisted wiring (on the front and rear shock actuators).

The absence of a speedometer signal can cause the light to come on, but usually, other systems will also be affected (steering, engine management, ABS/ASR, etc)

Let me know if you need a wiring diagram (but the circuit may be more complex than you think).

 

Most common failure is an actuator or the gear in top of the shock. From experience I can tell you that the light will go out as soon as you fix your problem, no need to hook up to a computer and clear the stored code. You need to check the rears now that you’ve checked the fronts and they look ok. If the rears also look ok, there may be an electrical fault with one of the actuators. I’ve had two actuators fail electrically. They looked good, turned back and forth with the ignition, but were bad. I used Captain Z CNC to repair then. I’ve had all 4 actuators rebuild, two had some kind of electronic failure.

 

Hi all.
I'm adding my findings to this post as it appears to be the most recent and technical regarding the actuators. There's a bit of a learning curve to figuring out if these work as intended, and I'd like to save everyone else some time and $ if you're diy inclined.. seems to be a lot of these forums, I love it.

My suspension light had been on since I got the car. After the selling dealer misdiagnosed it (that's another story) I got into it myself. After having read the posts about twisted front left actuator cables I started there and pulled both the fronts off and checked the resistance values across the wiring. The twisted cable showed some values in the 30 MOhm range, where the non-twisted one had them in the kOhms.
I assumed the twisted wiring was bad and figured I had nothing to lose, so started to tear that actuator apart. Turns out the cabling was not broken the same values were present a the motor itself. I guess the twising has to get really bad for cables to tear out. They are cased in epoxy at the actuator end.

So I got my new actuator and guess what.. the 30MOhm values are correct, I destroyed a perfectly good actuator. At least I get to share with you guys how these work and how to check them.there are 2 hall effect sensors on each motor board, triggered by a small rotor. I was expecting some encoder mounted on top (precise encoders used in surgical robotics are my day job), but no, it's just a "dumb" feedback circuit. All the position tracking in done within the suspension Ecu itself.

So basically, this is what you're looking for,
according to the letters Stamped on the actuator connector
Between B &C: this is the connection to the motor itself. You should see <10 ohms

Between A&E and A&F: these are the hall feedback lines. They test as diodes. If you're checking with resistance you're looking for 20-30Mohm with your multimeter leads connected one way, and open when you connect the multimeter the opposite way. The better way to check is in diode tester mode if your multimeter supports it. You should see .5v drop in one direction. Either way it should be easy to spot failed halls. Mine showed <30 kohms either direction on the failed unit.

After installing another new actuator to replace the shorted out one my suspension light went away. Lots of drama over a 20 cent hall effect chip . I know these can also fail mechanically, I just hope to demystify the electrical failure. There are videos around of just applying power to the motor to check it, which is misleading. The halls will fail before the motor itself.

Happy fixing,
Roger

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Very nice. Thank you for the diagnostic information. I will add this to my files for reference.

 

Hi all,

I had a rather annoying episode with another one of these actuators failing. I guess they're reaching the age where stuff just fails. In my annoyance I was considering the possibility of just making my own, given the cost or these items. I'm not sure it will work out yet, given the current and feedback would have to match exactly, but I wanted to gague if there would be any interest in the community that would make this project worthwhile.
The goal is to produce an actuator that works just as original, but is fully serviceable and available at the fraction of oem cost.
The downside would be that based on assemblies available off the shelf, the finished actuator would be about an inch taller than the factory unit. That's not a problem on the 550 front, but I haven't checked out the rears yet.

Any feedback, positive or negative is appreciated.

Attached are some pic of 3d printed interface to the strut - basically the bottom of the actuator, just for a dimensional check. Fit like a glove. A production version would be printed out of nylon or abs to withstand the under-hood heat
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There may be some interest from F355 owners (especially at a lower price point), but the extra inch might be an issue (and the colour might look a little odd)

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Maybe black would be less conspicuous.

As they can currently be repaired by Captain Z CNC (albeit with a conspicuous white ring around the case), you might have to get the price pretty low to attract buyers.

 

Ian,

Thanks for your thoughts. I didn't realize the actuators are so prominently on display in the 360, and their height matches the surrounding shielding.
The rebuild option is probably pretty convenient to most, and the cost is hard to argue with. And if anyone insists on the original look, oem actuators are still available.
That pretty much settles it.

- Roger