Doosan B20S-3 - Page 75

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MicroController Control System Troubleshooting
PROBLEM 21
Overtemperature is ON and Display = and EP.
Lifting performance slow. Drive and power steering
operation normal.
POSSIBLE CAUSE
Pump motor overheated; Pump motor thermostat (thermal
switch) defect; Open wiring; Display defect;
Logics defect.
CHECKS
Let the truck cool for 15 minutes.
Overtemperature indicator ON Normal display
Disconnect the battery. With the pump motor
at close to room temperature, disconnect the
pump motor thermal switch connector.
Check continuity of thermal switch.
Should have continuity below 123°C (253°F).
Continuity No continuity
Check continuity of wire #42 between pump
motor thermal switch to PE-1.
Continuity No continuity
Repair or replace switch.
Replace logics.
Pump motor was overheated, resume normal
operation. If repeats occur, check pump motor
current draw or operating cycle for excessive
lifting and tilting.
Check continuity of wire #44 between pump
motor thermal switch connector to PD-2.
Continuity No continuity
Repair or replace wire.
Repair or replace wire.