HGTC Suspension Error Icon

Hi All,

I have a beautiful 2004 575, on which the prior owner upgraded the shocks to HGTC equipment. I've read that this is not an uncommon "upgrade", and that there are quite a few 575's out there with various elements of the HGTC package added.

But as I've also read, earlier model 575's (not that a 2004 is early, but early for the HGTC package I guess?) don't have compatible ECU's that work properly with the HGTC shocks. As a result, my mechanic says the "suspension error" graphic on the dash I have to stare at is just something I need to live with, but doesn't indicate any problem.

So my question, is he right? Has anyone figured out a way to get rid of the warning icon?

Appreciate any insight, thanks!

Best,

Joel

 

Credit to tazandjan
"The 575Ms before 52556 do not have the steering position sensor that sends a lead into turn signal to the shock absorber ECU to tighten up the outside actuator. The late shock ECUs, like the HGTC one, look for that signal. If not present, a suspension warning lamp illuminates. Works fine, just gives a lamp."

 

Understood, thank you for the reply... Agree that is the issue, but wondering if anyone has found a workaround that turns the error icon off? Maybe I'm more anal than most, but really hate staring at it on my dash

 

Well, you could always use the Sharpie method!

 

Actually now that I was thinking about a workaround, I don't believe this is what's happening to you after all. The shocks themselves don't have any electronics on them, the only thing the ecu is connected to is the actuator. So swapping shocks alone while keeping the same electronics wouldn't make logical sense to cause an error.

I think what I quoted was meant for someone who has the hgtc ecu installed on an early car.

So now I actually think the mechanic might be wrong, and the problem could be either a bad actuator, or bad ecu.

Do the 575's suffer from the same twisting cable actuator problem that the 550's have? That could be an easy thing to inspect visually for a potential problem.

 

Affirmative, swapping the shock ECU to HGTC pre-52556 will put on the lamp, but changing the shocks and the shock mounts will not cause any problems. We have owners that have swapped to the HGTC shocks. The Sachs shocks on the 575M have internal actuators and do not suffer the same problems as the 550's Bilsteins.

An SD2 should be able to diagnose the suspension lamp issue, possibly a Leonardo. There are several things that can cause a suspension lamp.

 

Thanks, that's great info... I will have to check if the PO also swapped the ECU when he did the shocks. And if he did, is it an expensive part / tough to find to switch back to the original ECU?

 

Joel- Might be easiest to check the part number. HGTC is 210578. What is the serial number or assembly number of your 575M?

 

Looks like mine is assembly number 52049... From what I have read the 210578 shocks fit cars earlier than 52556, but give the warning lamp due to the missing steering position sensor?

So does that mean the ECU isn't relevant, it's a steering position sensor issue?

 

Taz is the expert here but as I understand non HGTC cars don’t have that steeeing position sensor or it’s harness at all to provide feedback to that ECU.

 

Could Joel have one of our friends flash his ecu to remove the signal?

 

Not sure how that works, but if it does I like the sound of it...

 

Joel- It is the shock ECU that gets the feedback from the steering position sensor, not the shocks. There is a normal connection from the shock ECU to the shocks, on all 575Ms. Joel's is a very early 04, so she has the straight center pipes (51797), but not the steering position sensor.

D- All post AN 52556 575Ms have the steering position sensor and updated shock ECUs, not just HGTC. Ferrari screwed that one up assuming the 575M's more advanced acceleration sensors could do the lead into turn signal to the shock ECU well. They could not since accelerometers lag, so they updated the 575M in Nov 2003 to add a steering position sensor like the 550 and 456s. One reason why later 575Ms do not really need FHP.

 

How do you know all this? You are like a walking Maranello library

 

Erik- As I learned, I wrote it all down.

Another interesting fact is that the HGTC Motronic ECUs and the HGTC TCU will only function correctly when used together. Either by itself results in really squirrely shifting.

 

How do the ECUs impact my left leg ;-)

 

Thank you for all this information, really can't find this anywhere but the experts here at Fchat. I've actually printed out Fchat threads for my mechanic that have proven helpful

So if I understand correctly, my early 2004 does not have the steering position sensor which is needed to interface with the HGTC shocks, and that's causing the suspension error lamp. Is there a way to add the sensor to an earlier car? Or somehow "cheat" the system to ignore the error / turn off the lamp?

 

Joel- No, the shocks have nothing to do with what you are seeing unless one of them is faulty. The steering position sensor does not interface with the shocks, only with the shock ECU.

D- Not too much.

 

Interesting, that's the first time someone has told me that, will need to get my mechanic to check for other sources of the error lamp. Thanks!

 

Joel- See post no 13.

 

OK, thanks for remind me of that info... So it is the shock ECU in the HGTC setup that is looking for a connection to the steering position sensor, and there's no sensor to connect with. Is there a way to reprogram the shock ECU to fool it into thinking it's got that connection, or similar? Or just something have to live with so long as the car has the HGTC shocks?

 

Trevor might be able to do it, but nobody else I know. Maybe Eric from France.

Right now you do not even know if you have an HGTC shock ECU. If you do, swapping back to a good early shock ECU will cure it, if that is the problem. You need someone with an SD2 to diagnose.

 

Thanks, I will discuss with my mechanic on next visit... Think this gives me all the info I need.

I suppose "reverting" to original shocks, and selling the HGTC units to someone who might want them, is also an option to consider.

 

Joel, If you do consider swapping to originals, I might have interest in trading you! @360trev is going to have his hands all up in my 575 ECU ...hopefully soon!!!

 

Anyone do a swap and have thoughts as to the ride difference between original shocks and HGTC? I don't track the car, just use for weekend drives in the mountains and highway miles. Am sure there are threads I should search.