ABS ACCUMULATOR TESTING

Prior to 1990 the only realistic way to diagnose a ABS fault was to use the Saab ABS tester. On cars from 1990 & on a revised method can be used to determine the actual faults. See the pages below:

ANTI LOCK LIGHT AND BRAKE FLUID LIGHT FLASHING ON BRAKE APPLICATION?
YOU MAY NEED AN ACCUMULATOR.

The ABS system used on 1988-1993 SAAB 9000 and 1990-1994 Classic 900 operates at pressures close to 2000 psi. The accumulator stores enough brake fluid, under pressure, to allow about 12 power assisted stops before the electric pump must run to bring the pressure back up.

Test your accumulator in the following manner:

With the key in the run position and the engine off, (radio off too!) pump the brake pedal until you hear the pump begin to run. Listen for the pump to stop running. Then step quickly and firmly on the brake pedal 10 times in about 5 seconds. If the brake fluid and antilock lights come on prior to the 8th repetition you should replace the accumulator. If the lights come on within 4 repetitions, consider the vehicle unsafe and replace the accumulator immediately.

Quick diagnosis no assist on ABS Mark 2 cars.

Check fuses (all 3) check for power at pump relay large red wire. If no power, find out why. If you have power, Jump large red to large yellow wire. Pump should run, if not check pump ground.
If pump runs, disconnect jumper, pump brake pedal till hard, and turn on key (engine off) and check for 12 V at double blue lead from pump relay, if 12V replace pressure switch, it should have been grounded, assuming a hard brake pedal. If 0 volts try a new relay. Once you get the pump running check accumulator and the rest of the system.