Syd B.

I've checked the archives, but haven't seen any viable explanations for my problem.

I had a brake job done about 500 kms ago and today, my "anti-lock" warning light came on with, of course, the beep. After turning off the engine and restarting, the light went out, but the issue recurred 10 minutes later. Any thoughts?

Jeff Curtis

Mine does this on hot days, and usually at the track...after a few seconds, or after shutting the car off and re-starting, it goes away.

The high-pressure pump needs to build up pressure sometimes...and the bells and whistles go off to indicate this.

THAT, my friend, is the only explanation I can give.

I have a C2, without the HIGH pressure braking system found in C4s, but there's still a pump that needs to pressurize once you start the car...if the pressure is below the required level, your lights/alarm will indicate such low pressure until it is up to par.

I may be WAY off on this one, but that's my side of the story and I'm sticking to it! <img border="0" title="" alt="[Wink]" src="wink.gif" />

DaveK

Doesn't low pressure cause the pressure light to come on? In the mornings, I see pressure and ABS light on until the pump recharges. If it's only the ABS light I would have thought the most likely cause was a speed sensor failure. But I am totally guessing.

Syd B.

Thanks guys. I like Jeff's assessment better. It won't cost me money!

Adrian

Dear Syd,
What model 964 have you got. Your warn sounds like a C2 with the vacuum boost. Your problem is not uncommon after brake work. Mechanics can damage the wiring or the sensor. Howeve rbefore I say more please tell me which 964 you have. There is a technical review in the rennlist technical section on this subject. I am surprised you did not find anything in the archives because this problem is not uncommon. A proper answer depends on C4, C2 or Turbo.
Ciao,
Adrian
911C4

PS: The C2 has no pressure warn system. Only brake fluid level monitoring.

Syd B.

Hello Adrian. My car is a C2 Cab. I checked the brake fluid level and found no problem. I drove the car all day today and the warning light mystery did not recur.

Thanks,

Syd

Adrian

Dear Syd,
You may have a dicky wheel speed sensor connector. You will just have to keep an eye on things. These intermittant problems are the hardest to find.
If you can get the problem to stay around it wil be easier for find.
Check relay R-34. This supplies the power and relays do fail.
Ciao,
Adrian
911C4

mjshira

I have this same issue. I was searching for the FAQ. If anyone has a link that'd be awesome, thanks

Livefreeandrive

Ihad this issue twice. Once i discovered a loose ground from wheel sensor to trailing arm and last week driving home from the track...beep beep.......cycle ignition a couple of times and it went away. My brake fluid was a little high and the track stress made it puke a bit?

AlfredF

I had the same problem and after stating the problem on the dutch Porscheforum several members advised me to put some extra brakefluid (more then the max. level) I did and the problem never came back.

(if you put to much in it then it drips out thru the tube just behind you front wheel (driver-side) so no problem)