Pump/Motor Monitor Circuit

NAME OF CODE:
Pump/Motor Monitor Circuit

WHEN MONITORED:
The test is conducted on a continual basis when the pump/motor should be off.

SET CONDITION:
The pump/motor relay supplies power to the pump/motor located in the hydraulic control unit. It is controlled by the Controller, Anti-lock Brake (CAB) through cavity 16. The relay output voltage is monitored by the CAB at cavity 20. When the pump is off, the monitor line should be pulled low through the pump/motor windings to ground. When the pump is on the monitor line should be high. The trouble code is stored if voltage of the monitor line (cavity 20) is above 6 volts for 3 seconds when the motor is commanded off.

POSSIBLE CAUSES:
- Open pump/motor windings
- Open pump/motor output circuit to CAB cavity 20
- Open pump/motor ground circuit
- Pump/motor relay output circuit shorted to B(+)
- Loose or corroded connector terminals
- Relay box not connected to the hydraulic control unit
- Pump/motor relay control circuit shorted to ground
- Failed relay box