Komatsu PC88MR-10 Shop Manual page 868

40 Troubleshooting
Troubleshooting of electrical system (E-mode)
No. Cause
Defective personal
15
code relay
Defective alternator
16
(internal short circuit)
Defective starting motor
17
(Internal defect)
Defective diode D01
18
(Internal open or short
circuit)
40-380
Procedure, measuring location, criteria, and remarks
a If no failure is found by check on Cause 8, this check is not required.
a Before performing troubleshooting, check that the head lamp lights up.
1. Turn starting switch to OFF position.
2. Interchange personal code relay (R07) with light relay (R05).
3. Start engine.
If engine starts, original personal lock relay is defective.
1. Turn starting switch to OFF position.
2. Turn starting switch to ON position.
Between alternator R terminal and
Voltage
ground
1. Turn starting switch to OFF position.
2. Turn starting switch to START position and perform troubleshooting.
Between starting motor terminal B
(SB) and ground
Voltage
Between starting motor terminal C
(SC) and ground
If power supply and starting input to starting motor are normal but starting
motor does not rotate, starting motor is defective.
1. Turn starting switch to OFF position.
2. Disconnect connector D01 and connect T-adapter to diode.
a Measure it with diode range of multimeter.
Between D01 (male) (1) (+) and (5) (-)
Between D01 (male) (5) (+) and (1) (-)
Between D01 (male) (2) (+) and (6) (-)
Between D01 (male) (6) (+) and (2) (-)
Input from
alternator
Max. 1 V
generation
Power
20 to 30 V
supply
Starting
input to
20 to 30 V
starting
motor
No continuity
Continuity
No continuity
Continuity
PC88MR-10