Cayenne - PASM / Supension fault / Code 1772 / Clueless

[Albert C]

Dear everyone! 

 

Let's see if someone can give me a bit of light. 

 

Like one month ago, my Cayenne air suspension compressor started making noise after driving, with car turned off and closed. It won't stop working. Finally the maxi 40a fuse blew out, and subsequently Chassis System Faulty yellow message popped up. 

 

After replacing battery and 40a maxi fuse, everything appeared to be ok. 

 

A week after, compressor started working too much again, same 40a maxi fuse blew out, and instead of yellow message Chassis System Faulty, we unlocked the red one : Warning Chassis System. 

 

After happening all this, what I observed : 

 

Car is able to retain air and keep leveled whilst compressor is disconnected or working temporarily if I put a new fuse. When I put another compressor fuse I can operate suspension up and down to all levels, till compressor decides to blow fuse again. 

 

So, it seemed there was no leakage on any air balloon, as car was able to maintain level. 

 

I brought the Cayenne to the workshop, error 1772 was showing, Implausible Signal - Wire from Level Control Pressure Sensor. 

 

Finally they decided to change compressor as it wasn't in good shape. Everything was working ok, till next fuse blew out, due to overload, and temperature rising. They took out the compressor, and it seemed, new compressor blew out the brown pressure line, so following procedures, they cut the brown line and inserted again. Everything was working fine. For a couple of days. 

 

Car was still able to maintain height, despite two or three ocassions, where randomly the car dropped down from front axle or rear axle, never both at same time. As soon as I put the compressor fuse, car returned to normal. 

 

Right now suspension is still not working, showing same error 1772, but now is Passive / Sporadic - Wire from Level Control Pressure Sensor.  instead of Implausible Signal - Wire from Level Control Pressure Sensor. 

 

As per what I see, there seems to be no leaks on pressure lines to front and rear axle, as it's able to maintain height. When suspension hasn't been able to maintain height on one of ir's axles , It's easy to hear a loud noise coming out of compressor area. So it's easy to identify where air is blowing from. 

 

When new fuse is working, suspension operates normal, average time from level to level (10 secs). Till fuse blows. 

 

It seems compressor is overheating when trying to put more air than needed. Why is trying to put more air on? I don't know, nor mechanic knows. 

 

I don't know if it can be the Suspension ECU, the air tank, maybe a sensor or whatever. 

 

Think last time, mechanic told me, pressure going out of compressor was 12 (can't remember unit) , and tank was "processing" only 7 (can't rememember unit) , so there was a difference of 5 units between what compressor was doing, and what was remaining. 

 

I'm absolutely lost, and not ready to get to Porsche dealer without having a minimum idea of what can be, and what cost it may have... 

 

If someone has experienced something similar, or someone has some clues, or advice, it would be highly appreciated. 

 

Regards from Spain! 

 

Albert C. 

 

 

 

 

Edited May 20 by Albert C

[Loren]

Fault code 1772 Pressure sensor signal wire

Possible cause of fault
- Short circuit to B+ in the wiring of pin 84 of the level control module
- Short circuit to ground in the wiring of pin 84 of the level control module
- Open circuit in the wiring of pin 84 of the level control module
- Level control module receives implausible signal from pressure sensor
- Pressure sensor faulty
- Level control module faulty

 

[Albert C]

Thanks Loren! I’ll give a try! And I will also speak with the guy at the workshop. 
 

Btw, I was considering purchasing a workshop manual for repairs, I’ve seen couple of webpages where they sell them, but there are many options even for same model year, and I was in doubt. Any recommendations? Would like to have it handy for any problem that may arise in future. 
 

I’ll let you know Loren!

 

thanks thanks thanks!

[Albert C]

I don’t know if this may help, but eventually between 5th and 9th of May, I got some errors that got cleared, and didn’t came back. 
 

Sorry for Google translation on image. 

[Albert C]

So car is out of the workshop. They replaced valve block, everything worked perfectly during 120 kms distance, and after refueling, it popped up again chassis system failure, and after that warning chassis system, two fuses blown up again.

Yesterday my icarsoft was registering data. Today car had no error, just a blown fuse after driving again, I’ve replaced it, and when I tried to scan with icarsoft, no data was available, and it’s not reading any data from PASM, but all other parameters (engine and so on) are readable. I’m really frustrated and I just want to throw up the car. Two months, more than 1,5K spent and 0 solutions. And as icarsoft is not working, I can’t check which parameters are wrong, but thanks for your help anyway!