I have an Anti-Lock warning light that will come on once in a while. If I restart the engine the light goes out for several miles and may not return for several days. Sometimes, it shuts itself off. Does anyone have ideas as to what the problem might be?
Thanks,
Steve

Submitted by stevejag@sbcgl… on Sun, 07/24/2011 - 12:42

Edited on 2011-07-24 12:45:33

Stephen,

You can assess the function of the accumulator somewhat easily.
With your ignition off, firmly pump your brake pedal 30-40 times. That completely exhausts the accumulator pressure. Then, turn the ignition on and listen for the pump to run, and time it. The pump runs to pressurize the accumulator. If it runs only a few seconds, the accumulator is junk. It should take 30-60 seconds for an accumulator to be charged with pressure, and the pump to turn off.

After the pump turns off, repeatedly press the brake pedal [slowly, but firmly] to see how many brake applications you get before the pump starts to recharge the accumulator. [you may want to have someone else handy to watch for the pump to start] You should get 4-6 brake presses before the pump starts the recharge process. If the pump starts every time the brake is pressed, you need an accumulator; if you get the 4-6 presses, the accumulator is good, anything in between tells you it is weakening.

That will assess the accumulator, but the pattern of your warning light makes me think you have another issue, possibly a 'combined pressure switch'. That is a pricey item also, so I think it should be diagnosed by someone who understands this brake system and can do it properly.