Chuckthetruck

I have a strange problem on my 993, ABS are only working on 3 wheels. Scary enough I discovered this on the Nürburgring, when I locked up my right front wheel going into Kallenhard.

I have since testet this on gravel roads several times, and ABS are pulsing on the three other wheels, but not fromt right.
The pedal feel is great, not spungy, new brake fluid, car brakes 100% straight (until it locks up). Sensor are brand new, no fault codes.

Tried to search for this problem on the forum, but found no topics with my problem. Although it seems like a good old flushing of the abs unit might be a good idea, and maybe a testing of the valves in the unit.
Anyone got a pinout read, so I can test this?

Remeljej

if the ABS knows it has a fault, it is supposed to shut the whole system off, whats interesting is that if the speed sensor is working fine, that the unit didnt notice when you locked up the wheel, it should see the speed flatline, and then try and pulse that wheel circuit,

can you data log with a durametric while braking hard? to see if it is trying to work, but somehow isnt?

mpruden

I'd scan the ABS computer for codes. Certainly it must know there is a problem and could point you in the right direction?

Chuckthetruck

I don't have equipment to log or scan computer unfortunately, maybe this would be a good time to buy one...

If the problem are a valve in the ABS unit that doesn't work, or are clogged, maybe the ABS unit would be fooled somehow.

When I bought the car, it had a ABS fault code, which was the sensor on the front right wheel. Bought a new one from Pelican Parts, and fault code dissapeared.