brett968

Air suspension but no PDCC or rear steering

rrd1288

Mystery then. Thursday cant come soon enough.

Mootz

I've been chasing the same issue on my 2019 Panamera GTS. It started at about 18k miles when it picked up a vibration during a drive in the snow. Snow had accumulated in the wheels during the drive and the car began to shake. I retuned home (just a mile or 2) and cleared the rims of the snow. I went back out for a test drive. Same vibration.

There is distinct vibration in the chassis that occurs at 57 mph. You can feel it in the seat and floor. The steering wheel does not shake. The vibration does NOT change with throttle position or with the application of the brakes. Gear changes have no effect. It even vibrates while coasting in neutral at 57 mph.

I assumed I had thrown wheel weight or something. I had previously scheduled service appointment, so while car was at the dealership for an oil change they road force balanced the tires. No change.

Soon the weather warmed up so I switched off of my winter tires/rims and onto my other set of rims with summer tires. Same vibration.

I returned to the dealership and they replaced all four summer tires (fronts were worn, but I went for all four) along with the cardon shaft. No change.

Now they said all Panameras with 21" wheels have this problem. They tried to prove their point by fitting the car with a new set of 20" wheels from another car. No change--same vibration. While the 21" wheels have a harsher ride, this is an oscillation/vibration. Not a harsh ride.

I took the car to a private mechanic. They put the car on the lift and accelerated to 57 mph. The front end shakes. Their suggestion was to return to the dealership have them check/replace the front axels/differential.

I brought it back to the dealership once again, and after a week they returned the car stating nothing is wrong.

I too find the problem to be intermittent. I travel the same road while commuting to work. Sometimes the vibration is horrible and other times none existent. I also find if I park for a few hours and then say go to lunch the vibration is back.

I've also noticed the vibration is worse on very smooth roads. If the pavement is rough it rarely happens.

rrd1288

This is getting interesting, I was thinking if swapping the rims didn’t solve the issue it could be the rear differential but the front could also be the culprit. Surprised to see many having the same issue. Let’s see if we can solve it.

Norge911

To OP, can you change title to vibration at 57mph vs CPO issue.

I purchased my 2018 ST turbo 4 weeks ago. Air suspension and rear axle steer. My car have the exact symptoms as Mootz. 57-58 mph have the worst bouncing.
thankfully, I’m either driving at 35-45mph or 70mph. Don’t spend much time in the 57 -64mph range.

It is very intermittent, I did drive at 57-58 and changed gear (increase rpm), changed suspension setting to firm, and had zero change in the bouncing/ vibration.

I stopped by best service dealer in Houston and spoke to my SA advisor. He stated he have had two customers with this problem plus the CEO of dealer had a brand new ST 4S with same issues. They have not been able to solve it. SA also looked service bulletins and nada on this issue. One customer keeps coming back but they have not had success in solving the issue.

over Christmas I will change alignment and see if that changes things. Probably not but I’m doing it for better tire wear and tire longevity anyway

rrd1288

I dont think im able to change the title.

Mootz

I also change the suspension settings; trying every combination of ride height and firmness. If anything I think the bouncing/vibration is less when using the firm setting--which is counter intuitive. Further reinforces the thought of a drive train issue.

I played around with tire pressures over the months including using "Comfort" pressures. Actually seemed worse.

For the record my GTS is equipped with Air Suspension, Rear Axle Steering incl. Power Steering Plus, and PDCC Sport incl. Porsche Torque Vectoring Plus (PTV+), on 21" wheels (both winter and summer sets are 21")

rrd1288

Just an update, the rims were swapped from a 2022. Im still testing it but the intense vibration I was having is for the most part gone. I still have a little here and there especially at night when its cold and that has to be attributed to the size and nature of having 21 inch rims. Will keep this updated.

Norge911

I have conducted more research and collected more empirical data and these are my findings;

This should be valid for all Panameras with air suspension.

The rear spoiler will raise at 56mph/ 90mph
the car will lower itself 10mm at the same time for increased stability. This is hard to find and now I can’t find my link again

in high setting, car will raise 0.8” at speeds up to 20mph
in low setting it is 1” lower

today I drove the car in Normal mode and changed ride height to Low. Then set speed at 57 and 58mph. Tried this a few times.
no bouncing nor any oscillating movements.
The Low setting is below the 10mm auto lowering at 56mph.

If I speed right through 56mph, ie 40 to 70, nothing.

I don’t think it is mechanical but electronic. Either the speed sensor that supports this function or position sensor on suspension is bad or the suspension module. (Maybe US cars don’t have the 10mm lower function but we have a ROW suspension module - crazy theory). This will cause suspension to bounce up and down while driving 56-60mph while whatever system is trying to figure out correct level at speed?

I plan to take car to dealer over Christmas and as them to check or replace any sensor that activates spoiler and suspension position sensor.

can anyone else try my test as described above and let us know your findings?

rrd1288

I dont think the air suspension moves that fast to cause that kind of vibration. I test drove the 2022 Panamera 4 with air suspension and my old rims, definitely rode softer than my turbo, but it had the identical vibration at 62.

Mootz

I've driven in all of the combinations of modes and suspension heights, with and without the rear spoiler locked in up position. None have any effect on the vibration.

Mootz

I ran a test using the NVH App. (PDF report attached.)

The results show first order vibrations (vibrations that have the same frequency as the wheel rotation) that occur between 55-59MPH. See page 2 of the report. There are no 2nd order (drive shaft related vibrations), or 4th order (engine vibrations) to speak of.

Since I can rule out tire/rim issues, that leaves drive train components that generate first order vibrations, axels and differential, etc.

Thoughts anyone?

Duc Hunter

@rrd1288 sounds like you have a winner. Something is wrong with those wheels. The little built you get there and there with eh new wheels could be a tire slightly out of round or out of balance. Or maybe a flat spot. Many tires get minor flat spots over night, and they come out as the tire warms up. Even here in Florida that happens, and it is far more noticeable in winter. In colder weather they are more pronounced over night, and take longer to go away (5-10 min). And we are rarely below 40F here in the dead of winter.

Also many CPO cars also were sold with an additional warranty on the wheels, tires, minor dents and windshield. It covered replacement and refinishing of wheels as part of it. Sounds to me like you need a new set.

Norge911

Wheels are easy to check with balancing machine and check for roundness and per Mootz, not the problem per his report.

so is it a 4 wheel drive problem?

On the Panamera, there is clever box on the transmission where forward shaft goes on an angle to the front diff and one output shaft axle goes through the engine block. See picture.

One of these axles bad and out of balance?
Bearing for the axle going though the block out of spec?

Read thread again and Mootz great investigation. His finding at indi shop with front end vibrating.
if it were to be the bearing for the axle going through the block, is it better or worse when warm ?
ie worse at first 15 min into drive or 1 hr into drive?

Mootz

The vibration seems worse when the cold--driving after sitting for a few hours/overnight (not weather conditions).

I don't think the drive shaft from the transmission to the front differential is the cause of the vibration since its rotational speed does not match the rotational speed of the wheels (1st order vibration). But who knows!

The best analogy I can make is that it feels like driving a car that has sat too long and has flat-spotted tires. There is a definite vertical up-and-down component to the oscillation. It usually improves some while driving, but rarely goes away completely. I know it's not a tire issue since I have tested with 4 different sets of tires and wheels. Also there is no vibration or shaking in the steering wheel with is usually the case with flat-spotting. Besides, tires do not develop flat spots after sitting for 2-3 hours.