PASM failure with lowering?

2 wks ago I had H&R lowering springs installed. Car has PASM . Yesterday I was driving in standard mode (non-sport mode) and after about 20 minutes the PASM failure message came on. I tried swithing to sport mode and the sport mode failure message came up. I parked, turned the car off and re-started and everything seemed fine....but after a few minutes the PASM failure message came up again. suggestions? ideas?

Could be the failure that the Porsche tech was talking about when using springs with PASM that weren't designed for PASM . Keep us informed as to he culprit because it could be something else as well.

this is a known issue with PASM and lowering springs...i think it had to do with progressive vs linear type springs and most current lowering springs are progressive, thus not suitable for Caymans with PASM . do a search on 'springs' to research and good luck...

What is the reason for lowering the car - is it for appearance,performance or both? My CaymanS with PASM looks and handles just fine so am I missing some benefit from not lowering?

i had seen the discussion regarding the issue with PASM and lowering and I have been skeptical that there is an issue. Perhaps someone with a technical background could describe how the PASM works and why a progressive rate spring would be a problem. I thought the PASM system is a little servo motor on top of the shock that opens/closes a valve to decrease/increase flow and damping. So the valve is either open or closed..that is it. Why would a progressive spring be a problem? BTW - the car handles fine - even with the "failure" message. There is no mechanical failure of the strut....perhaps it is just a loose connection from the mechanic not putting the connectors back together right?????? Roger - Stock springs handle great. I did it for looks...although if I were to race a Cayman I would lower it for the aero benefits and for the lower CG... plus I would use much heavier springs. The spring rate on the H&R sport springs is only very slightly heavier than the stock springs. I would say that I found the stock springs a bit floaty at the limit and the H&Rs tighten'd it up.

Greg Merril - a quick search and i found this...the explanation is there. http://www.planet-9.com/topic.asp?TOPIC_ID=3700&FORUM_ID=4&CAT_ID=1&Topic_Title=PASM+and+lowering+springs&Forum_Title=Cayman+Tech

I personally can't understand how a shock would know if the spring was linear or progressive. All it 'sees' is motion, up and down. The rate of this shock travel obviously varies, and probably is a little different with a progressive versus a linear spring, but how would it be any different than just hitting the same bump a little faster or slower with the stock springs? Even if you look at the change in velocity (acceleration) I cannot see how a properly designed shock could perform well under all driving conditions and then fail from a simple spring change; what could possibly be different WRT shock velocity or acceleration with a different spring that would not be expected to be seen under typical driving conditions? If there is any truth to this rumor, I believe it would be due simply to the lower ride height and that the shock was bottoming out (in spite of the bump stops somehow).

Adax - that is exactly what I was thinking...thank you for articulating it better. mt647 - I had seen that post before I got the H& R springs , but, for the reasons stated by Adax, it did not make sense to me that it would really be a problem. unfortunatly I will be out of town for a week and I wont be able to get to the shop to have them take a look at it until after the 12th.

One possibility could be that the load on the valve inside the shock, the one that PASM opens and closes is too great with a lowered progressive spring and when PASM goes to close it, it blows the valve after awhile, just a thought...

It isn't the shock 'seeing' the difference between the two types springs; it is the software that is watching. The software is seeing values that it thinks are out of range. The software is trying adjust the shocks based on the inputs it is reading; it doesn't like what it sees... Edited by - sleepless on 07/04/2006 8:33:28 PM

Sleepless, The PASM shocks are not actively adaptive - it does not adjust based on conditions - it is either in "regular" mode or "sport" mode and that is manually selected by the driver. The shorter and slightly firmer springs that are now on my car should actually reduce the range of travel. The new springs move a little faster in a smaller range of motion, but should be well within the operating range of the shock. The more I think about it the more I think it must be either a bad connection on the shock valve servo or the valve could be damaged so it stuck and the servo burned out? I am quite sure there is no sensor inside the shock to detect any problem.

It was my understanding that PASM is ALWAYS actively adaptive, but that there are 2 main maps, normal and sport mode and that PASM reacts within limits for each.

Yes, K-man S is correct. It is well documented in the Porsche literature and on their website. PASM stands for Porsche ACTIVE Suspension Management, and it does in fact adjust its damping characteristics continually and actively based on the spring activity and the driver control inputs. In other words, itcontinually monitors your driving style and the road condition and adapts instantly from split second to split second. The valve opens and closes progressively, not just 'on' or 'off'. As a result, you MUST have PASM -spec springs. Oh, and FYI, the computer controls each shock absorber independently. The normal and sport programs each have a range of operation in which they adapt, and the ranges overlap somewhat. The Cayman brochure shows a graphic representation of the two ranges. Edited by - P-nut on 07/05/2006 1:48:25 PM

Greg - K-Man S is right - PASM is an active adaptive system, using a myriad of sensors to continuously monitor road surface conditions, driver input, attitude and ride height at each wheel... Brad This is from the Porsche Web site: <blockquote> <div class="innerContent"> Porsche Active Suspension Management ( PASM ) is an electronic damping control system. Optional on the Cayman S , it offers continuous adjustment of the damping force at all four corners of the car. The damping rates are adjusted throughout each journey based on current road conditions and driving style. Agility and driving pleasure are significantly enhanced while retaining the car’s natural ride quality. Equipped with PASM , the car rides 0.39 inches lower than with the standard steel-sprung suspension. During each journey, the driver can choose one of two setup modes: ‘Normal’ and ‘Sport.' While the 'Normal' setting balances performance with comfort, the ‘Sport’ settings are generally much firmer, enabling greater agility on the racetrack. In either mode, the system responds to changing road conditions and driving style by applying the optimum damping rate on each individual wheel. The rates are selected from a range of map options, which are specially adapted to the unique dynamics of the Cayman S . The movement of the body is continuously monitored under acceleration, braking and cornering maneuvers, as well as on poor road surfaces. Other sensors provide additional information on lateral acceleration, steering angle, brake pressure and engine torque. A dedicated control unit provides real-time analysis and damper adjustment as defined for the respective setup mode (‘Normal’ or ‘Sport’). The result: greater stability and more consistent occupant comfort. If, when ‘Sport’ mode is selected, the quality of road surface drops below a certain threshold, the system immediately switches to a softer rating and restores the car’s traction and grip. When the road surface improves, PASM returns to the original, harder rating. The system remains active in ‘Normal’ mode, too, automatically switching to a harder rating if the car is driven more assertively. As the dampers become stiffer, the car becomes more stable and driver control is improved. </div> </blockquote>

Greg, What I'm concerned about here is that if you do have a PASM failure and your dealership notices that you have aftermarket springs that they may choose not to cover your PASM failure under warranty, and depending upon the proximate cause of the failure they may be correct in doing so. If that scenario does take place then the next question is whether or not H&R will cover the cost since they told you that the springs would work with PASM (assuming they told you that or are marketing the springs as such). There is a PASM -compliant suspension available from RSR911 now, some pics and a brief description are in the Cayman Shop in the Cayman GT section, along with a couple of photos. I found it interesting from their description that they actually have a dual set of springs and a new strut/shock that wires in the same way the PASM factory shocks/struts do. I *think* their system is made by Eibach , but I'm not certain.

I'm a bit worried about a warranty claim. I did explicitly ask the US H&R distributor about PASM and he stated that the springs are compatible and went further to say that H&R provides the springs OEM to Porsche so they have constant communication on this stuff.

Greg, If your computer is throwing error codes, then these springs are not PASM compatible no matter what they told you, and you should have a talk with the H&R folks about their claims to be such. I've also heard that Bilstein will be coming out with a PASM compatible PSS9 system soon. I believe it's in testing now. brad

It is always best to get a written warranty if one is implied. Most aftermarket providers don't offer anything but the sales staff are artful in their promises in order to close the deal. I know for you this is advice you cannot take but hopefully others will listen and learn.

I just spoke with John at H&R. He confirmed that, as far as H&R is concerned, this spring is PASM compatible. He said that they have been using progressive springs to lower the 911 with PASM for a few years without any problem. He suspects that one of the electrical connections came loose. I will find out when I get back from my trip.. Thursday or Friday next week.

In: Issue 148 July 2006 911 & PORSCHE WORLD : How to drive your 911 Part 5 of your comprehensive guide to getting the best from your 911. This month, Mark Hales looks at the four wheel drive cars including the new generation 911 Turbo The author references a discussion with Porsche engineers about PASM not being able to work when the997 is loweredusingshorter springs.

Greg, did you find what the problem is yet? I'm guessing a loose connection...

I set an appointment to take it in to AtSpeed Motorsports to have them check it out - they installed the springs. They also need to fix some loose interior trim stuff that is not quite right. It is interesting that everything was fine for 2 wks and then I got the error message. Now everytime I start the car the error message appears when I drive for about 20 yrds... would suggest that something changed - like a loose connection.

um... PASM is working now... I have not had the car looked at yet. This morning I had the PASM failure message come up consistantly 4x after shuting the car off and re-starting and the SPORT mode could not be engaged. It felt like it was stuck in the stiffer mode. I drove it to work and didn't mess with it...but when I drove home from work it worked fine. I switched back and forth from SPORT to NORMAL several times to try to force the failure if possible - could not cause any problem. This kind of intermittent problem points to a likely loose connection. I will still have the car checked on Tuesday to see if we can find the loose connection or any other issue.

Car is back from the shop. PROBLEM SOLVED. it was a loose wire. PASM back up and running.

Congrats, glad to hear not anything more serious. Keep an eye on it and let us know how it gets along!

Greg, I'm glad to hear that, so the H&R lowering springs were not the cause of the pasm failure. Any others with pasm lowering experiance?