Air Suspension Not Possible : I will defeat it.
09-26-2018, 11:28 PM
#16
Subscribed. My dealer threw a strut assembly at the problem without fixing it, blaming the original issue on a leak. Same symptoms after the new strut assembly so I'd prefer not to empty my wallet on guess work. Thanks for documenting your tribulations.
09-26-2018, 11:38 PM
#17
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It seems even the dealers are ill-equipped to deal with this issue as it is apparently uncommon.
The car seems to be doing the same thing, basically starting the compressor all the time. I feel like eventually it would fill the accumulator enough but I have no idea how long that will take without it being filled with nitrogen first
The car seems to be doing the same thing, basically starting the compressor all the time. I feel like eventually it would fill the accumulator enough but I have no idea how long that will take without it being filled with nitrogen first
09-27-2018, 12:05 AM
#18
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You might already know, but the manual states a couple times that it is important to not lower the car if the air springs are empty as it will damage the air-spring struts as they will develop creases which leads to their failure. They state: "If the vehicle has been driven with one or more empty air springs, these air springs must be replaced." It's also why new air springs need to be pre-filled before installing so they also don't crease.
The filling process is a guided filling process through the PIWIS tester and done before the Cayenne is set down onto the ground by filling at the accumulator then running the bleed process. Once filled/bled through the PIWIS instructions, calibration is performed.
The filling process is a guided filling process through the PIWIS tester and done before the Cayenne is set down onto the ground by filling at the accumulator then running the bleed process. Once filled/bled through the PIWIS instructions, calibration is performed.
09-27-2018, 12:12 AM
#19
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Right, which is why I support the spring at the normal ride height with a floor jack, then lower it a bit until it pumps up some, then repeat this process until the air spring is full and I can remove the jack.
I don’t ever let the car down on an empty air spring.
just like I don’t have a shop manual, or a piwis, or the time and money to deal with the dealership. But I do have a multimeter, a durametric, a soldering iron, and a lot of torx bits.
I don’t ever let the car down on an empty air spring.
just like I don’t have a shop manual, or a piwis, or the time and money to deal with the dealership. But I do have a multimeter, a durametric, a soldering iron, and a lot of torx bits.
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09-27-2018, 07:56 AM
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Garrett I appreciate you sharing the info from the manual. I have found I care less about the modern shop manuals (compared to the 944 days) because every damned thing requires a special tool.
I admit there is some risk taking trying to get this to work on my own. But even if I burn up a compressor or two or break a few struts, I’ll be financially ahead at the end.
I DO have the help of a couple of good techs and I will be getting that nitrogen fill today.
I admit there is some risk taking trying to get this to work on my own. But even if I burn up a compressor or two or break a few struts, I’ll be financially ahead at the end.
I DO have the help of a couple of good techs and I will be getting that nitrogen fill today.
09-27-2018, 11:02 AM
#21
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Trying to boil down the process here, for us peasants with no PIWIS or icarsoft or icarscan or whatever it's called these days. This is how you can get by enough to get the car driveable to a shop that can do the nitrogen fill.
In my opinion, these repairs can be done at home, without a computer, but you need a good large floor jack (or lift), and you need someone (unfortunately, a dealer probably) who can fill the accumulator with nitrogen afterwards.
There are 2 main failure modes.
Failure 1: Strut air bag leak.
Failure 2: Compressor doesn't work.
Normally Failure 1 happens slowly and is noticed by such symptoms as
-1.a. "not possible" going above normal height
-1.b. car drops level as parked (left it parked in normal, return to low level)
-1.c. one corner of the car seems to droop
-1.d. "chassis faulty" or "chassis failure"
Failure 2 occurs over time but is exacerbated by a Failure 1. Symptoms:
-2.a. "not possible" going above normal height
-2.b. lots of blinking of arrows when changing heights but the height won't change
-2.c. can't hear compressor run (because it's not running)
-2.d. "chassis failure" due to compressor running too often, or to it not running at all (broken wire or relay
In the case of failure 1, strut replacement is somewhat straightforward, with the following extra precautions:
1. before starting work, disable level control (hold level switch in "up" position for 10 seconds).
2. replace spring/damper/strut and reinstall wheel. allow the wheel to touch the ground but DO NOT fully release the jack/lift. Allow the jack to support most of the car's weight on that corner. adjust the jack so that the car is mostly level
3. undo the battery ground that's just in front of the driver seat (there's a little plastic rectangle frame in the carpet you pull forward from the top, and a body-color 13mm nut that holds the cable on) for 10 minutes.
4. replace the batter ground you just undid then start the car and re-enable level control. ensure the hood and doors are closed. since you made the car level with the jack, it probably won't do anything.
5. with the car still running, get out and close the door again. slowwwwly release the jack to drop the car about an inch or two onto the new strut, but then tighten the jack again to support the car at a lower level. the car should respond by pumping enough air into the strut to get it to come back up a bit.
6. repeat step 4 a couple of times. You don't want to put full weight on the strut until the car has pumped a good amount of air into the strut.
7. If possible, take the car to a shop (drive on low level or tow it) that has dry nitrogen and the correct fitting to purge and re-fill the accumulator, to help dry the system out some.
7. Exercise car through the different heights. be sure to allow LOTS of time for the compressor to cool off between changes. It gets VERY hot in a hurry.
For failure 2,fix your leak first, then replace the relay second:
1. On left hand drive cayennes, its under the dash.
2. remove the one torx screw to get the beauty cover out that's above the pedals.
3. You'll see, just to the right of the brake pedal, a big (t30 I think) torx screw. undo it.
4. The top of the relay panel is hinged in place; just rotate towards you a bit and push the panel up, and it'll pop out so you can pull it down and work on it.
5. the "top left" (I use this term loosely since it matters which way you hold the panel) of the relay panel is slot number 1. each slot has a number cast into the plastic. hard to see, but it's there.
6. Remove the relay from slot one (there's a tiny tab you have to pull to get the relay out) and replace it with a new one
If your problem persists, you can then replace the compressor $$$ using the following precautions:
1. inspect your new compressor. look at the wires. make sure they are all connected! if you decide to bench test using 12V, be sure you know what you're doing because reverse polarity would probably damage the compressor
2. disable level control (up on the level switch 10 seconds)
3. jack up the car and USE JACK STANDS because there's a chance you'll lose air pressure and the car will drop on any wheels that are still on the ground!
4. remove the passenger side plastic rocker panel protector (lots of torx screws)
5. unplug the two electrical connectors and cut the zip ties holding them in place
6. undo the 3 13mm bolts that mount the compressor/valve block to the car
7. support the assembly so you can work on the FRONT END of the compressor for the following fittings:
8. undo the small black air line on the bottom (12mm wrench...flare wrench is nice for getting it going but not necessary),
9. undo the larger inlet hose (for all you people screaming "it's a closed system," yes there is a big hose right on the compressor that pulls in ambient air lol) which has a collar you depress into the pump and then the hose male nipple just pulls out
10. undo the blue air line at the top (12mm again)
11. undo the bolts that attach the compressor brackets to the mount (10mm)
12. undo the black brackets that attach to the compressor (torx) and reinstall them on the new compressor
13. assembly is the reverse of removal. If you replace the brass fittings (my new pump came with them already threaded into the ports), they are a pain because the little collar has to be situated just so. There are two white lines on each air hose- you want to see one but not both of them after it's installed.
14. if done correctly, the valve block prevents loss of nearly any air. only the air in the lines between the compressor and valve block escape (negligible)
15. place the car back on the ground but AS BEFORE be careful not to just drop the car- if you lost any air, you'll need to support the car a bit until the compressor can refill lost air
16. undo the battery ground that's just in front of the driver seat (there's a little plastic rectangle frame in the carpet you pull forward from the top, and a body-color 13mm nut that holds the cable on) for 10 minutes.
17. replace the battery ground you just undid, make sure hood is closed, get in the car, close and lock the doors, turn ignition to position 1, and wait to see if any failures pop up.
18. Normally the car runs the compressor for a split-second right as you turn the ignition on just to test it. if you listen closely you'll hear it.
19. if all is well, or even if you have a chassis failure or faulty code, go ahead and start the car and listen for the compressor to kick on.
20. re-enable level control. keep listening.
21. if the compressor runs and runs and doesn't want to stop, check again for leaks AND get a shop to fill the accumulator with nitrogen.
Codes that you'll probably see:
354 (haven't figured this one out; I think it's related to low air volume or compressor fault
284 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
257 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
312 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
1D1 compressor changeover valve (the small, 3-wire plug) is broken
1E1 compressor changeover valve (the small, 3-wire plug) is broken
anyone with a shop manual please help me out with the meanings of these codes so that future DIYers will know
In my opinion, these repairs can be done at home, without a computer, but you need a good large floor jack (or lift), and you need someone (unfortunately, a dealer probably) who can fill the accumulator with nitrogen afterwards.
There are 2 main failure modes.
Failure 1: Strut air bag leak.
Failure 2: Compressor doesn't work.
Normally Failure 1 happens slowly and is noticed by such symptoms as
-1.a. "not possible" going above normal height
-1.b. car drops level as parked (left it parked in normal, return to low level)
-1.c. one corner of the car seems to droop
-1.d. "chassis faulty" or "chassis failure"
Failure 2 occurs over time but is exacerbated by a Failure 1. Symptoms:
-2.a. "not possible" going above normal height
-2.b. lots of blinking of arrows when changing heights but the height won't change
-2.c. can't hear compressor run (because it's not running)
-2.d. "chassis failure" due to compressor running too often, or to it not running at all (broken wire or relay
In the case of failure 1, strut replacement is somewhat straightforward, with the following extra precautions:
1. before starting work, disable level control (hold level switch in "up" position for 10 seconds).
2. replace spring/damper/strut and reinstall wheel. allow the wheel to touch the ground but DO NOT fully release the jack/lift. Allow the jack to support most of the car's weight on that corner. adjust the jack so that the car is mostly level
3. undo the battery ground that's just in front of the driver seat (there's a little plastic rectangle frame in the carpet you pull forward from the top, and a body-color 13mm nut that holds the cable on) for 10 minutes.
4. replace the batter ground you just undid then start the car and re-enable level control. ensure the hood and doors are closed. since you made the car level with the jack, it probably won't do anything.
5. with the car still running, get out and close the door again. slowwwwly release the jack to drop the car about an inch or two onto the new strut, but then tighten the jack again to support the car at a lower level. the car should respond by pumping enough air into the strut to get it to come back up a bit.
6. repeat step 4 a couple of times. You don't want to put full weight on the strut until the car has pumped a good amount of air into the strut.
7. If possible, take the car to a shop (drive on low level or tow it) that has dry nitrogen and the correct fitting to purge and re-fill the accumulator, to help dry the system out some.
7. Exercise car through the different heights. be sure to allow LOTS of time for the compressor to cool off between changes. It gets VERY hot in a hurry.
For failure 2,fix your leak first, then replace the relay second:
1. On left hand drive cayennes, its under the dash.
2. remove the one torx screw to get the beauty cover out that's above the pedals.
3. You'll see, just to the right of the brake pedal, a big (t30 I think) torx screw. undo it.
4. The top of the relay panel is hinged in place; just rotate towards you a bit and push the panel up, and it'll pop out so you can pull it down and work on it.
5. the "top left" (I use this term loosely since it matters which way you hold the panel) of the relay panel is slot number 1. each slot has a number cast into the plastic. hard to see, but it's there.
6. Remove the relay from slot one (there's a tiny tab you have to pull to get the relay out) and replace it with a new one
If your problem persists, you can then replace the compressor $$$ using the following precautions:
1. inspect your new compressor. look at the wires. make sure they are all connected! if you decide to bench test using 12V, be sure you know what you're doing because reverse polarity would probably damage the compressor
2. disable level control (up on the level switch 10 seconds)
3. jack up the car and USE JACK STANDS because there's a chance you'll lose air pressure and the car will drop on any wheels that are still on the ground!
4. remove the passenger side plastic rocker panel protector (lots of torx screws)
5. unplug the two electrical connectors and cut the zip ties holding them in place
6. undo the 3 13mm bolts that mount the compressor/valve block to the car
7. support the assembly so you can work on the FRONT END of the compressor for the following fittings:
8. undo the small black air line on the bottom (12mm wrench...flare wrench is nice for getting it going but not necessary),
9. undo the larger inlet hose (for all you people screaming "it's a closed system," yes there is a big hose right on the compressor that pulls in ambient air lol) which has a collar you depress into the pump and then the hose male nipple just pulls out
10. undo the blue air line at the top (12mm again)
11. undo the bolts that attach the compressor brackets to the mount (10mm)
12. undo the black brackets that attach to the compressor (torx) and reinstall them on the new compressor
13. assembly is the reverse of removal. If you replace the brass fittings (my new pump came with them already threaded into the ports), they are a pain because the little collar has to be situated just so. There are two white lines on each air hose- you want to see one but not both of them after it's installed.
14. if done correctly, the valve block prevents loss of nearly any air. only the air in the lines between the compressor and valve block escape (negligible)
15. place the car back on the ground but AS BEFORE be careful not to just drop the car- if you lost any air, you'll need to support the car a bit until the compressor can refill lost air
16. undo the battery ground that's just in front of the driver seat (there's a little plastic rectangle frame in the carpet you pull forward from the top, and a body-color 13mm nut that holds the cable on) for 10 minutes.
17. replace the battery ground you just undid, make sure hood is closed, get in the car, close and lock the doors, turn ignition to position 1, and wait to see if any failures pop up.
18. Normally the car runs the compressor for a split-second right as you turn the ignition on just to test it. if you listen closely you'll hear it.
19. if all is well, or even if you have a chassis failure or faulty code, go ahead and start the car and listen for the compressor to kick on.
20. re-enable level control. keep listening.
21. if the compressor runs and runs and doesn't want to stop, check again for leaks AND get a shop to fill the accumulator with nitrogen.
Codes that you'll probably see:
354 (haven't figured this one out; I think it's related to low air volume or compressor fault
284 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
257 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
312 don't know but may be level out-of-range, can't adjust (too high or too low) or could be from unplugging the connector on the strut
1D1 compressor changeover valve (the small, 3-wire plug) is broken
1E1 compressor changeover valve (the small, 3-wire plug) is broken
anyone with a shop manual please help me out with the meanings of these codes so that future DIYers will know
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09-27-2018, 12:00 PM
#22
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Since I see no talk about refilling the system before trying it - I'm guessing at least part of the system was down to air? That might be a lot for the compressor to overcome. The manual is pretty specific about refilling it after any work.
09-27-2018, 01:00 PM
#23
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deilenberger,
In my case the system was pretty much 90% air (which is to say it was about 73% nitrogen) because I had to inspect all the lines due to a fear of contamination (couldn't explain why neither compressor would work....old one was broken and new one had a broken wire).
It turns out that, no matter what the manual says, I don't have a big bottle of dry nitrogen and the porsche-specific regulator and adapter in my garage. I don't have the PIWIS to put the car into fill mode either.
Yes, it is a lot of volume for the compressor to move. I believe the compressor would overheat again and again trying to fully refill the system if you let it just run. However, it is capable of refilling the system enough to get to Low level and drive, so long as you are careful about how much you let it run so that it doesn't overheat and damage the pump, motor, or relay. I would recommend it be driven straight to a dealer that can bleed and fill with nitrogen per the manual.
Everyone is entitled to take their car to the dealer and let the dealer handle it, exactly like the shop manual says to, with all the special tools, and the PIWIS computer, and the bottle of puuuuuure puuuree ultra-dry nitrogen, for every little air suspension issue.
Anyone can do it with the right tools (and charge you boat-loads of money to do it), but as 958s continue to be bought by second, and third, and fourth, and fifth (or twelfth as I was of my 955) owners who are more inclined to DIY, or are financially obligated to DIY, there will have to be methods developed that require less special tools (and more ingenuity).
In my case the system was pretty much 90% air (which is to say it was about 73% nitrogen) because I had to inspect all the lines due to a fear of contamination (couldn't explain why neither compressor would work....old one was broken and new one had a broken wire).
It turns out that, no matter what the manual says, I don't have a big bottle of dry nitrogen and the porsche-specific regulator and adapter in my garage. I don't have the PIWIS to put the car into fill mode either.
Yes, it is a lot of volume for the compressor to move. I believe the compressor would overheat again and again trying to fully refill the system if you let it just run. However, it is capable of refilling the system enough to get to Low level and drive, so long as you are careful about how much you let it run so that it doesn't overheat and damage the pump, motor, or relay. I would recommend it be driven straight to a dealer that can bleed and fill with nitrogen per the manual.
Everyone is entitled to take their car to the dealer and let the dealer handle it, exactly like the shop manual says to, with all the special tools, and the PIWIS computer, and the bottle of puuuuuure puuuree ultra-dry nitrogen, for every little air suspension issue.
Anyone can do it with the right tools (and charge you boat-loads of money to do it), but as 958s continue to be bought by second, and third, and fourth, and fifth (or twelfth as I was of my 955) owners who are more inclined to DIY, or are financially obligated to DIY, there will have to be methods developed that require less special tools (and more ingenuity).
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09-27-2018, 01:05 PM
#24
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I also intend to try and devise an off-the-shelf way to fill the accumulator with nitrogen (or at the very least, compressed air from a regular shop compressor) so that that car doesn't need to be driven low on charge.
09-27-2018, 01:06 PM
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Anyone can do it with the right tools (and charge you boat-loads of money to do it), but as 958s continue to be bought by second, and third, and fourth, and fifth (or twelfth as I was of my 955) owners who are more inclined to DIY, or are financially obligated to DIY, there will have to be methods developed that require less special tools (and more ingenuity).
09-27-2018, 01:10 PM
#26
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Now we're talkin'
Photos have been taken, and more shall be. I would love to put something together and will do a vid. But seeing as how I haven't crossed the finish line yet (still gotta get that nitrogen fill- being done today) and do some testing, I don't want to count my air struts before they hatch!
Photos have been taken, and more shall be. I would love to put something together and will do a vid. But seeing as how I haven't crossed the finish line yet (still gotta get that nitrogen fill- being done today) and do some testing, I don't want to count my air struts before they hatch!
09-27-2018, 01:36 PM
#27
Burning Brakes
Since I'm in the DIY phase of Cayenne ownership I'm subscribed and following with anticipation. With that said, I'll seriously consider converting to nice coilovers, assuming that's an option, if/when I have a major air suspension failure.
09-27-2018, 02:18 PM
#28
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after what I've been through, a set of GTS springs with aftermarket dampers definitely crossed my mind. I use the air on the beach and when loading/unloading my trailer, though. And I tow a lot, and it is marvelous for load leveling
09-27-2018, 09:57 PM
#29
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Update, still have some code for a pressure sensor short to b+. Have to sort that out. Car is still not responding properly to commands on the toggle switch
09-28-2018, 01:07 AM
#30
The only specialized tool you really need from Porsche is the adapter to connect a hose from a pressure regulator on a nitrogen tank to the acummulator on the car. The tool is available from Porsche for $10. Everything else is readily commercially available.