(E) Pump Run Time Too Long

SYMPTOMS: Pump run time from no pressure to the high limit switch point takes longer than 40 seconds.

POSSIBLE CAUSES: Faulty battery, malfunctioning charging system or electrical circuits other than ABS circuits, low accumulator precharge, pressure switch malfunction, damaged Powermaster III, malfunctioning pump, relief valve, low fluid level (rear chamber).

INSPECT

Testing Wheel Rotation:

1. Turn off ignition. Disconnect wiring harness at the pump connector. Turn on ignition. Using a DVOM, check voltage of Pin A to ground.
2. If less than 12 volts exist at Pin A, check the battery, charging system and non-ABS electrical circuits for damage.
3. Turn off the ignition switch, connect pump connector. Depressurize the Powermaster unit, refer to "Depressurizing the Powermaster III Unit" in Service and Repair. Remove accumulator and install J 37118. Install accumulator on J 37118.
4. Bleed Powermaster III Unit at its bleeder valves or perform an "ABS Solenoid Bleed and Checkout Test", refer to "Powermaster III Bleeding" using 94-00101-A.
5. Observe pressure gage while turning on ignition. Is there a sudden jump in pressure from 0 psi to 500 psi or more almost immediately after the ignition is turned on? (This initial jump in pressure is the amount of accumulator precharge). If not, the accumulator must be replaced.
6. Note pressure when the motor shuts off or the high pressure limit is reached. Is this pressure more than 19,995 kPa (2,900 psi)? If so, replace the pressure switch.
7. Using 94-00101-A, monitor the pump state while applying the brakes slowly between 1 and 3 times. Note the low pressure point when the pump turns on.
8. Does the motor turn on at 13,790 kPa (2,000 psi) or higher? If not, replace the accumulator pressure switch since it is turning on the motor at too low a point, refer to "Depressurizing the Powermaster III Unit".

Reservoir Components:

9. DO NOT APPLY THE BRAKES WITH THE RESERVOIR COVER REMOVED. If the pressure switch functions properly, visually check the pump inlet in the reservoir to be sure it is not clogged. Turn on the ignition switch. If the inlet is clear, place one end of a clear plastic hose over the relief valve in the reservoir. Hold the other end of the tube (pointing downward) in the rear reservoir chamber. If fluid flows through the tube into the reservoir, replace the relief valve. If fluid does not flow through the tube, place one end of the clear plastic hose over the booster return port (54 in image). Again, hold the other end of the tube (pointing downward in the rear reservoir). With the ignition still on, if fluid flows through the tube, replace the Powermaster III Unit. If no fluid flows, replace pump and motor.