Strange ABS issue on 964 RSR
08-16-2005, 07:04 PM
#1
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Strange ABS issue on 964 RSR
Hi to all, I am the lucky owner of a 964 RSR and had something strange happen to me at Spa-Francorchamps last week.
As I was heading to eau rouge, starting to brake, the car's ABS chime would go on and the big exclamation mark would come on.
After reset, this would go away, with one exception, I drove it in the paddock and hit a big bump and again it came on.
Any ideas? It puzzles my mechanic's hammer and it doesn't seem to be covered in Adrian's book...
TIA
JM
As I was heading to eau rouge, starting to brake, the car's ABS chime would go on and the big exclamation mark would come on.
After reset, this would go away, with one exception, I drove it in the paddock and hit a big bump and again it came on.
Any ideas? It puzzles my mechanic's hammer and it doesn't seem to be covered in Adrian's book...
TIA
JM
08-16-2005, 08:59 PM
#4
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Some info here: https://rennlist.com/forums/964-forum/217574-abs-indicator-light-on.html but to quote our friend Garrett from that thread.....
Marc
p.s. And if it fixes your problem, we'd all love to see more pictures of your car, please!
Originally Posted by garrett376
It is common for the ground connection near the ABS valve block to be corroded - several times people have posted this intermittent problem, and solved it by unscrewing, cleaning, and reinstalling the various ground points in the front hood (there are three, I think). From memory reading those posts, it seems the ground closest to the ABS valve block (behind the battery) is the culprit.
C4 guys - if you want to see your PDAS functioning more easily, install the green PDAS bulb in your combination instrument...
https://rennlist.com/forums/964-forum/106325-green-pdas-activation-light-in-dash-gauge-how-activate.html
C4 guys - if you want to see your PDAS functioning more easily, install the green PDAS bulb in your combination instrument...
https://rennlist.com/forums/964-forum/106325-green-pdas-activation-light-in-dash-gauge-how-activate.html
p.s. And if it fixes your problem, we'd all love to see more pictures of your car, please!
08-16-2005, 09:02 PM
#5
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p.s. And if it fixes your problem, we'd all love to see more pictures of your car, please!
08-16-2005, 11:16 PM
#7
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Is this a new problem? Doesnt usually happen on the track? Or have you just started tracking the car? Have you changed your tires to a different brand/stiffer sidewall? Changed spring rates?
When you hit a bump hard, at high speed, with stiff/track tires, sometimes the ABS brain thinks that there is a fault with one of the sensors (due to vibration/noise picked up by the wheel sensor). Its not that uncommon, and is one of the reasons the factory installed an ABS cutoff/reset switch.
I have the problem all the time with the ABS on my 944T track car. But this is a street/stock ABS system and I am running springs that are 5 times stiffer than stock and running stiff sidewall track tires. So Im surprised that your RSR (with I assume is a race tuned ABS) would be having that problem. If you tracked your car before and not had the problem, look for something wrong - loose sensor at the hubs, or loose connector, or as mentioned before: a loose ground wire.
When you hit a bump hard, at high speed, with stiff/track tires, sometimes the ABS brain thinks that there is a fault with one of the sensors (due to vibration/noise picked up by the wheel sensor). Its not that uncommon, and is one of the reasons the factory installed an ABS cutoff/reset switch.
I have the problem all the time with the ABS on my 944T track car. But this is a street/stock ABS system and I am running springs that are 5 times stiffer than stock and running stiff sidewall track tires. So Im surprised that your RSR (with I assume is a race tuned ABS) would be having that problem. If you tracked your car before and not had the problem, look for something wrong - loose sensor at the hubs, or loose connector, or as mentioned before: a loose ground wire.
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08-17-2005, 01:14 AM
#9
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My Euro Cup does the same thing from time to time. It's on my 'things to do' list to check all the grounds near the ABS block as described in this thread.
Damn, I don't know what to be more envious of: the RSR or being able to drive Spa.
Damn, I don't know what to be more envious of: the RSR or being able to drive Spa.
08-17-2005, 04:18 AM
#10
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No you are correct, the 964 RSR ABS is not covered in my book. Nor is the RSR 993 system in my 993 book either. The racing ABS systems are NOT the same as fitted to the standard 964. There is no available information on these "Racing" systems. Efforts to crack this nut failed with both Porsche AG and RSR owners not providing anything.
If you have the cut off switch installed I recommend you check the wiring around this area.
The fault indicates a control unit failure or is directly related to power or ground inputs to the control unit.
Ciao,
Adrian.
If you have the cut off switch installed I recommend you check the wiring around this area.
The fault indicates a control unit failure or is directly related to power or ground inputs to the control unit.
Ciao,
Adrian.
08-17-2005, 05:11 AM
#11
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Originally Posted by Adrian
No you are correct, the 964 RSR ABS is not covered in my book. Nor is the RSR 993 system in my 993 book either. The racing ABS systems are NOT the same as fitted to the standard 964. There is no available information on these "Racing" systems. Efforts to crack this nut failed with both Porsche AG and RSR owners not providing anything.
If you have the cut off switch installed I recommend you check the wiring around this area.
The fault indicates a control unit failure or is directly related to power or ground inputs to the control unit.
Ciao,
Adrian.
If you have the cut off switch installed I recommend you check the wiring around this area.
The fault indicates a control unit failure or is directly related to power or ground inputs to the control unit.
Ciao,
Adrian.
Those who want pics, e-mail me, I have a few nice ones static and dynamic at various tracks- Brands Hatch, SPa, Castle Combe and Silverstone
JM
08-17-2005, 05:24 AM
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Originally Posted by jrotsaert
.......
Those who want pics, e-mail me, I have a few nice ones static and dynamic at various tracks- Brands Hatch, SPa, Castle Combe and Silverstone
JM
Those who want pics, e-mail me, I have a few nice ones static and dynamic at various tracks- Brands Hatch, SPa, Castle Combe and Silverstone
JM
Big mistake!!! Your email box will be flooded.
Post your pics HERE!!
08-17-2005, 12:01 PM
#15
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Man, JM, that sounds like a real bugger of a problem. I tell you what, my 89 C4 ABS works just fine, so I'll be a pal and trade you cars. I know, I know, I'm a saint, but that's what friends are for... Just PM me and I'll send you the address to ship the car to... 
Brian
Brian