Problem Main causes Remedy
Unusual noise is generated from al-
ternator.
Defective alternator Replace. (*)
Starting motor does not rotate even
when starting switch is turned to
START position.
Defective wiring Check, repair. (*)
Defective starting motor Replace. (*)
Insufficient battery charge Charge battery.
Battery disconnect switch at OFF po-
sition
Turn ON.
Engine shutdown secondary switch
at “STOP ENGINE” position
Set it to “NORMAL” position.
Apply the cover.
Pinion of starting motor repeats en-
gaging and disengaging (rattles).
Insufficient battery charge Charge battery.
Defective safety relay Replace. (*)
Starting motor turns engine sluggish-
ly.
Insufficient battery charge Charge battery.
Defective starting motor Replace. (*)
Starting motor disengages before
engine starts.
Defective wiring, defective ring gear
and pinion
Check, repair. (*)
Insufficient battery charge Charge battery.
Preheating pilot lamp does not light
up.
Defective wiring Check, repair. (*)
Defective heater relay Replace. (*)
Defective monitor Replace. (*)
Oil pressure caution lamp does not
light up when engine is stopped
(starting switch is at ON position).
Defective monitor Replace. (*)
Defective oil pressure caution switch Replace. (*)
When startability at low temperature
is poor, if you touch the outside of
the electric heater by hand after pre-
heating, it is not felt warm.
Defective wiring Check, repair. (*)
Wire breakage in electrical intake air
heater
Replace. (*)
Defective operation of heater relay Replace. (*)
Blown fuse of the heater Replace. (*)
Engine does not start.
(“L04” lights up on monitor.)
Damaged data in the controller Check, repair. (*)
Other system troubles Check, repair. (*)
PHENOMENA AND ACTIONS FOR CHASSIS
• For the remedies indicated with (*) in the remedy column, always contact your Komatsu distributor.
• In cases of problems or causes which are not listed below, ask your Komatsu distributor for repairs.
Problem
Main causes Remedy
Speed of travel, swing, boom, arm,
bucket is slow
Lack of hydraulic oil Set oil to specified level. See
CHECKS BEFORE STARTING.
Pump generates abnormal noise.
(sucking in air)
Clogged element in hydraulic tank
strainer, lack of oil
Clean. See EVERY 2000 HOURS
MAINTENANCE.
Excessive rise in hydraulic oil temper-
ature
Dirty oil cooler Clean. See EVERY 500 HOURS
MAINTENANCE.
Lack of hydraulic oil Set oil to specified level. See
CHECKS BEFORE STARTING.
TROUBLES AND ACTIONS OPERATION
3-264
To Next Page