(D) Low or No Boost Pressure

SYMPTOMS: Red brake warning lamp lit, amber ABS warning lamp lit, frequent pump running, pump not running, pump runs continuously.

POSSIBLE CAUSES: Internal Powermaster III leak, malfunctioning relief valve, malfunctioning pump, malfunctioning pump relay, malfunctioning accumulator pressure switch, blown fuse, loose or damaged wiring, low fluid level (boost side), reversed polarity at motor (motor runs backwards), reversed polarity at relay coil (motor won't run).

INSPECT

1. Turn ignition off and depressurize the Powermaster unit, refer to "Depressurizing the Powermaster III Unit" in Service and Repair.
2. Properly connect 94-00101-A to vehicle.
3. Perform an "ABS Pump Power Up Test" using 94-00101-A.
4. Note the TOTAL pump run time. This is the time between ignition on and pump shut off. If the pump does not run or runs continuously, refer to Codes 35 and 36.
5. If the total pump run time is 40 seconds or less, the Powermaster III is developing satisfactory boost pressure. If the total pump run time is more than 40 seconds, refer to test (E) "Pump Run Time Too Long".
6. Determine the pump off time by moderately applying the brakes and holding the brake pedal in the applied position. The pump off time is the time between brake apply and pump run. To determine the pump off time without a stopwatch, perform a "Powermaster III Bleed Down Check With Brake Pedal Depressed Test" using 94-00101-A.
7. If the pump off time is 50 seconds or less, a problem may exist in the Powermaster III. Refer to test (E) "Pump Off Time Too Short". If the pump off time is more than 50 seconds, the Powermaster III is adequately holding boost pressure. (E) Pump Run Time Too Long (F) Pump Off Time Too Short