Komatsu 170-3 Series Shop Manual page 181

TROUBLESHOOTING
Action by controller
• Red lamp lights up
• Red lamp lights up
• Limits engine speed to 1500 rpm
• Yellow lamp lights up
• Red lamp lights up
• Outputs speed signal 0 rpm
• Red lamp lights up
• Carries out open control of timing rail
• Limits engine speed to 1500 rpm
• Red lamp lights up
• Carries out open control of timing rail
• Limits engine speed to 1500 rpm
• Yellow lamp lights up
• Carries out open control of fuel pump
• Yellow lamp lights up
• Carries out open control of fuel pump
• Yellow lamp lights up
• No lamps light up
• No lamps light up
170-3 SERIES
ACTION TAKEN BY CONTROLLER AND CONDITION OF
MACHINE WHEN ERROR CODE IS DISPLAYED
Problem that appears on machine
• Engine cannot be started
• Engine speed goes down
• Engine output goes down
• Engine emits white smoke
• Engine stops
• Engine makes abnormal explosion
sound or emits white smoke, then
engine speed becomes 1500 rpm
• Engine makes abnormal explosion
sound or emits white smoke, then
engine speed becomes 1500 rpm1
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• Exhaust gas color is poor when
accelerating
• Engine output increases
• Engine output goes down
Probable cause
• Defective engine controller
• Excessive negative pressure at inlet port
of fuel pump
• Defective timing rail actuator or clogged
screen
• Broken injector O-ring
• Defective engine controller
• Defective timing rail actuator
• Defective wiring harness and connector
of timing rail actuator circuit
• Defective engine controller
• Defective engine speed sensor
• Defective wiring harness and connector
of engine speed sensor circuit
• Defective engine controller
• Defective timing rail pressure sensor
• Defective wiring harness and connector
of timing rail pressure sensor circuit
• Defective engine controller
• Defective timing rail pressure sensor
• Defective wiring harness and connector
of timing rail pressure sensor circuit
• Defective engine controller
• Defective fuel pump pressure sensor
• Defective wiring harness and connector
of fuel pump pressure sensor circuit
• Defective engine controller
• Defective fuel pump pressure sensor
• Defective wiring harness and connector
of fuel pump pressure sensor circuit
• Defective engine controller
• Defective engine speed sensor
• Defective wiring harness and connector
of engine speed sensor circuit
• Defective engine controller
• Defective boost pressure sensor
• Defective wiring harness and connector
of boost pressure sensor circuit
• Defective engine controller
• Defective boost pressure sensor
• Defective wiring harness and connector
of boost pressure sensor circuit
• Defective engine controller
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