Hint, how get rid of PSD failure indication
08-29-2012, 04:52 AM
#1
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Hint, how get rid of PSD failure indication
In my 928 S4 ym. 90 PSD system was indicating failure, but there was no error code when testing with tester. WSM says in that case the problem is in high pressure production.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
08-29-2012, 05:01 AM
#2
Rennlist Member
In my 928 S4 ym. 90 PSD system was indicating failure, but there was no error code when testing with tester. WSM says in that case the problem is in high pressure production.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
Good
, that fully proofs my theory which I was going to test somewhere during next year 2013 (see earlier thread: https://rennlist.com/forums/928-foru...the-issue.html ).
08-29-2012, 05:04 AM
#3
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Forgot to add: if you want to get your PSD-unit working again, this thread might further help you:
https://rennlist.com/forums/928-foru...procedure.html
https://rennlist.com/forums/928-foru...procedure.html
08-29-2012, 11:50 AM
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In my 928 S4 ym. 90 PSD system was indicating failure, but there was no error code when testing with tester. WSM says in that case the problem is in high pressure production.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
My analyze was, that motor is running but no producing high pressure. I removed the pump unit and starting the vehicle I got an additional error from ABS-system. Tester diagnose was error code #11, which has common parts with PSD and ABS. PSD-ECU can not separate in which system the fault is, in ABS or PSD therefore both faults are indicated.
The obvious reason for ABS error was missing Transverse Lock Valve in PSD system.
To eliminate ABS-fault indication and simulate transverse lock valve (nominal coil resistance 2,7 to 4 ohm ) I added 3,3 ohm/ 4W resistor into Transverse Lock Valve connector ( round plug with one male and female pin ).
To ensure good connection of resistor you should crimp female and male pin into resistor legs and isolate them with shrinking tube.
For my big surprise both error indicators ABS and PSD disappeared!
Disappearing of ABS fault was understandable, but why PSD no idea!
ABS is working fine, PSD communicates with tester. I have not had opportunity to remove the resistor to check if faults reappear, but I am pretty sure that my connection did not harmed PSD-ECU.
First off, welcome! What a great first post. I'm sure more and more of us will encounter these PSD issues. Please keep us informed if you discover a solution to the high pressure failure.
08-29-2012, 01:04 PM
#5
Drifting
An easier way to disable the PSD warnings at the instrument cluster, is to remove two wires from connector T23 located under the dash. Specifically, pins 3 and 9 from the ABS/PSD controller side, as shown in WSM wiring diagram for 1990, for cars built without PSD (M221).
This method is similar to RDK (M482) disable, where removing pin 8 from connector T23 disables the Tire Pressure Warnings.
This link shows a post of how to remove pin 8 from connector T23: https://rennlist.com/forums/9592768-post25.html
This method is similar to RDK (M482) disable, where removing pin 8 from connector T23 disables the Tire Pressure Warnings.
This link shows a post of how to remove pin 8 from connector T23: https://rennlist.com/forums/9592768-post25.html
08-29-2012, 01:14 PM
#6
Rennlist Member
Borland: good information, however be aware that by applying your method the ABS unit still remains non-functional with this occuring PSD-unit fault as Pevi reported.
So Pevi's workaround is much prefered if one want to drive around with at least working ABS (while sorting out the faulty PSD-unit in the meantime).
So Pevi's workaround is much prefered if one want to drive around with at least working ABS (while sorting out the faulty PSD-unit in the meantime).
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08-29-2012, 03:09 PM
#8
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Fully understood, and that is why I wrote: "... the ABS unit still remains non-funtional ... ".
In my eyes it is better to at least have a functional ABS while sorting out the PSD- unit, as well as having the warning popping up in the meantime (acknowledging only takes a second) so to be reminded of getting things fixed.
