Brittany964

My ABS warning light comes on when the car starts rolling, not when its idling. This seems to suggest that one of the wheel sensors is faulty or has a bad connection.

My question is this: If I pull the ABS fuse (No. 16) I know this will disable the ABS and the warning light. I realise the implications of having no ABS but if I brake carefully I shouldn't have too much of a problem until I get round to fixing the fault. BUT... are there any other implications? Will pulling the fuse affect anything else?

The reason I ask is that my car is about to undergo a 'Control Technique' test (the French equivalent of the British M.O.T.) and it obviously won't pass if the ABS warning light's on. They don't test drive the car so they hopefully won't register that there's a problem if I pull the fuse.

Any suggestions?

Laker

If they don't test drive the car, won't the light stay off if the car was just started and is only idling?

boxsey911

A friend of mine had what sounds to be an identical problem. After much investigating he found that it was caused by the ABS relay in the fuse panel (tall silver one at position R34). A new relay solved the problem.

DaveK

Does pulling the fuse really disable the warning light? That seems like a rather poor design.

sundog

I had this problem on mine and found that it was one of the sensors that was broken. When replaced the issue went away. You can test them one by one, don't have the instructions handy, but in my case one was physically broken.

Gregg-K

Howard, tell us a little more about how the problem manifests itself.

Does the ABS light illuminate consistently after the car starts out from a stop, and then reaches a given road speed? If so, that's a sign the ABS self-test is detecting a system fault.

Or, is the ABS light turning on unrelated to road speed, or the length of time the car has been moving? For instance, is it a road bump that causes the light to turn on? If so, it could be a bad connection somewhere in the system.

Also, does the warning "beeper" behind the dash come on at the same time as the ABS light?

.. Gregg

Brittany964

Gregg - the light comes on when the car reaches about 5 mph and stays on. The beeper sounds too although this can be stopped with the 'I' switch.

I've decided to start investigating by:
a) Checking battery positive terminal
b) Checking the relay in the fuse box for any obvious faults (Porsche owners are very few and far between in this part of France so I'm unlikely to find anyone who'll swap theirs with me to check)
c) Examining each wheel sensor in turn, clean them and check wiring
d) As very much a last resort I'll have to visit a Porsche main dealer and ask them to plug the car into their diagnostic system (I can hear the Euros tumbling away already)

Any other suggestions would be welcome.

boxsey911

Is there any chance that the ABS control module got unplugged recently while undergoing work? It needs to be seated 100% correctly otherwise it will throw a fault (light and buzzer). To check, lift the silver tab and unplug it and re-plug securely while holding up the silver tab and then press the tab down.

Gregg-K

If the ABS light and warning sound happen each and every time your car starts from a dead stop, and accelerates to 5 mph, then the ABS diagnostics are discovering a hard fault, as opposed to an intermittent or transient fault. As difficult as this may be to accept, diagnostics should be much easier to do.

.. Gregg