Power Steering Troubleshoot

[millerchris85]

First post!  Reasonably new owner of 2008 Cayenne Turbo ?

 

Looking for guidance on where to hunt for a power steering issue.  It seems like other owners have had quite the journey fixing these systems.

 

Symptoms

- Very little power steering assist at low speed

- Power steering whine at low speed, possibly all speeds (cannot tell with engine noise)

 

Cause

- Ice driving on a lake... either too much steering work, or something might have gotten wet/iced.  Trying to thaw it in the garage, but it is very cold here in MN right now.

- Power steering fluid level was at the min mark (may not be related)

 

I have searched pretty far/wide and learned that steering issues can include the servotronic controls (relay, transducer?), rack, and pump.  This topic reads like it is tranducer/wiring-related, but I would not necessarily expect a whining pump.

 

My question - if there is a servotronic issue, can it cause pump whine?  As in, some valve/restrictor is closed, forcing the pump to work hard?  If not, then it seems like pump failure.  I would rather not replace the pump if it is something else.

 

I ordered the iCarsoft POR-II unit in the hope it can help me see if there are active codes.

 

 

Edited January 22, 2019 by millerchris85

[ma77hewsu11ivan]

First check the fuse, then top off and/or flush w/ new steering oil (use a little hand pump to remove old oil from reservoir>add new while turning turning the steering wheel full clock LR>repeat until it looks clean) More detailed instructions around here somewhere. Hope this helps. -Matt

[millerchris85]

Thank you Matt!

[millerchris85]

I checked the 5A fuse - it was OK.

 

I flushed the steering fluid with a liter of Pentosin 202; it was coming out pretty clean at the end.

 

Unfortunately, the issue persists.  Oddly, I have noticed that I seem to have more steering assist at initial startup, before closing the driver's door.

 

The iCarsoft scanner did not show anything although I will try again.  It might not be able to access the steering module, or the steering codes may be under a different controller.

 

Is it known that the Durametric can see the steering controller and identify codes?

I might try removing the relay next to see if that makes a difference, although it sounds like the steering goes heavy when they fail.  Or maybe I can pull the fuse.  Other suggestions?

[millerchris85]

Removing the 5A fuse made no difference, nor did removing the Servotronic relay.

 

It seems plausible that the relay or transducer on the rack has failed, but the pump whine is significant.  At a dead stop, I only really get steering assist if I rev the engine; it appears the pump is the issue.

 

Unless it is known that pump failures are incredibly rare, and Servotronic problems can cause pump whine, I am leaning towards replacing the pump.  Thoughts?

[millerchris85]

Closing the loop on this one - it was indeed the pump.  I purchased a used unit ($115 versus $725), installed it, and have been trouble-free since.  The replacement pump is fairly loud, but this may be typical from what I have read.