E-1 Engine Does Not Start - Komatsu WA250-6 Shop Manual

400 Troubleshooting of electrical system (E-mode)

E-1 Engine does not start

E-1 Engine does not start
Contents of
• The engine does not start.
trouble
• Before starting troubleshooting, check the following.
a. Directional lever is not in N (Neutral).
b. Directional switch is not in N (Neutral).
c. Starting of engine is prohibited by function of KOMTRAX.
d. Battery cable is not disconnected from battery.
• The engine does not start, because the starting motor does not run due to troubles in the starting
Related
motor system and starting switch terminal C signal system.
information
• Check that fuse is normal.
(If it is broken, check the related wiring harness for grounding fault.)
• The input state (ON/OFF) to the machine monitor from the starting switch terminal C can be checked
with the monitoring function (Code: MONITOR PANEL 40900, D-IN-2).
• If failure code is indicated, carry out troubleshooting for it first.
1 Defective battery
Defective battery relay
2
(Internal trouble)
3 Defective fuse
Defective starting motor
4
(Internal trouble)
Possible
causes and
standard value
in normal state
Defective alternator
5
(Internal trouble)
Defective starting switch
6
(Internal trouble)
Defective multifunction
lever switch
7
(Internal disconnection or
short circuit)
WA250, 250PZ-6
Causes
The battery relay can be judged normal if operating sounds are audible
when the starting switch is operated.
• Starting switch operation in the order of OFF o ON o OFF
If the fuse is burn, the circuit probably has a grounding fault, etc. (See
cause 18.)
a Prepare with starting switch OFF (with wiring harness connected),
then turn starting switch START and carry out troubleshooting
Between terminals B (E30)
Between terminals C (E21)
If the starting motor does not run even if power supply input, battery
input and starting input is normal, the starting motor is defective.
a Prepare with starting switch OFF, then turn starting switch ON and
carry out troubleshooting.
Wiring harness between alternator terminal R
E02 (female) (1) – ground
a Prepare with starting switch OFF, then carry out troubleshooting with
starting OFF and START each.
Between (1) and (3)
Between (1) and (2)
Between (1) and (4)
a Prepare with starting switch OFF, then turn starting switch ON and
carry out troubleshooting.
Between (1) and (3)
Standard value in normal state/Remarks on troubleshooting
Specific gravity
Voltage
Starting motor
Power supply input
and ground
and ground
L02 (male) Position of switch
FNR (directional)
MLT (male)
Other than above
SEN03848-00
Min. 1.26
Min. 25 V
20 – 30 V
Starting input 20 – 30 V
Voltage
Resistance
OFF Min. 1 Mz
START
OFF Min. 1 Mz
ON
lever
N (Neutral). 20 – 30 V
1
Voltage
Max. 1 V
Max. 1 z
Max. 1 z
Voltage
Max. 1 V
3
40-400