"differential control off" warning light- ??
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Intermediate
Joined: May 2001
Posts: 47
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From: Goodyear, AZ
"differential control off" warning light- ??
This warning came up in red on the dash yesterday as I was driving. After I got to where I was going and left again, it stayed off, then when I went for a drive the next day it came on again. I read the owner's manual and it said it wasn't a priority warning and to bring the car in ASAP, which I will do next week.
I was just curious what this could be and hoping for something very minor. I am not a mechanic but if there's something I could easily check or do, please tell me. The car's an auto if that matters.
Any ideas?
Thanks,
Jay
I was just curious what this could be and hoping for something very minor. I am not a mechanic but if there's something I could easily check or do, please tell me. The car's an auto if that matters.
Any ideas?
Thanks,
Jay
Drifting
Joined: Aug 2003
Posts: 2,259
Likes: 3
From: Camarillo, CA, USA
The ABS controller has detected a fault with the PSD system. Unfortunately, you need a special computer to trouble shoot the fault code and indentify the source of the problem. In my area, the only shop's that have this computer are the two Porsche dealers.
It could be one of several problems, such as faulty PSD pump, PSD pressure switch, low/leaking PSD fluid, etc.
I'd first disconnect the battery for twenty minutes, then see if the fault code and warning light return.
It could be one of several problems, such as faulty PSD pump, PSD pressure switch, low/leaking PSD fluid, etc.
I'd first disconnect the battery for twenty minutes, then see if the fault code and warning light return.
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From: Ball Ground, GA
The PSD system uses brake fluid under pressure. The fluid should be changed periodically - very few cars have this important maintenance operation done. The only way to have this done is usually to use the Bosch Hammer, which usually means a Porsche dealer or specialists shop.
However, if you belong to the 928 Owners Club, there is a procedure on their members-only web site that allows DIY fluid changes. Highly recommended.
However, if you belong to the 928 Owners Club, there is a procedure on their members-only web site that allows DIY fluid changes. Highly recommended.
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From: Phoenix AZ
Jay,
I had this happen on my GTS and just flushing & changing the fluid was sufficient to fix it. However I took it to the local dealer first and they talked of corrosion and contaminated fluid and wanted to change the pressure vessel and the pump also. I talked to the mechanic a little and he said this was standard procedure because they didn't want to warranty the repair if it was possible I'd be back with a similar problem again soon. He said it would probably be OK with just a flush. But the service manager refused to do it - so they put it back together as was...
Considering the parts were well over $1000 (I think about $1300 for both) I took it elsewhere and after figuring out how to do the flush & refill an independant specialist shop fixed it and its now been great for over 18 months. All of you with a PSD - its a worthwhile maintenance item every 3-4 years, not too expensive if you have a shop with a bosch hammer (and the required special control cable!). Its even pretty easy to get to - hidden behind the driver side rear wheel (liner just has to come out).
Alan
I had this happen on my GTS and just flushing & changing the fluid was sufficient to fix it. However I took it to the local dealer first and they talked of corrosion and contaminated fluid and wanted to change the pressure vessel and the pump also. I talked to the mechanic a little and he said this was standard procedure because they didn't want to warranty the repair if it was possible I'd be back with a similar problem again soon. He said it would probably be OK with just a flush. But the service manager refused to do it - so they put it back together as was...
Considering the parts were well over $1000 (I think about $1300 for both) I took it elsewhere and after figuring out how to do the flush & refill an independant specialist shop fixed it and its now been great for over 18 months. All of you with a PSD - its a worthwhile maintenance item every 3-4 years, not too expensive if you have a shop with a bosch hammer (and the required special control cable!). Its even pretty easy to get to - hidden behind the driver side rear wheel (liner just has to come out).
Alan
Last edited by Alan; Aug 26, 2003 at 02:19 PM.
