Komatsu BR380JG-1E0, Shop Manual, Page: 700 / 841

SEN02095-00 40 Troubleshooting
12
BR380JG-1E0
E-4 Preheater does not operate 1
Trouble (1) When starting switch is turned to HEAT position, preheating monitor does not light up or flash.
Related
information
• Preheater monitor lights up when starting switch is turned to HEAT and starts flashing about 30 sec-
onds after to notify completion of preheating (It stops flashing about 10 seconds after).
• If engine coolant temperature is below 20°C, automatic warm-up system operates and preheating
monitor lights up for up to 30 seconds.
• Condition of starting switch (preheating) signal can be checked with the monitoring function.
(Code 04500 : Monitor input 1)
Possible
causes and
standard value
in normal state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective starting
switch (Internal discon-
nection)
a
Prepare with starting switch OFF, then keep starting switch OFF and
turn it to HEAT and carry out troubleshooting in each case.
Starting switch Starting switch Resistance
Between B – R1
OFF Min. 1 M
z
HEAT Max. 1
z
2
Disconnection in wiring
harness (Disconnec-
tion in wiring or defec-
tive contact in
connector)
a
Prepare with starting switch OFF, then carry out troubleshooting without
turning starting switch ON.
Wiring harness between P02 (female) (18) –
starting switch R1
Resistance Max. 1
z
3
Defective machine
monitor
a
Prepare with starting switch OFF, then keep starting switch OFF and
turn it to HEAT and carry out troubleshooting in each case.
P02 Starting switch Voltage
Between (18) –
chassis ground
OFF Max. 1 V
HEAT 20 – 30 V
Trouble
(2) When starting switch is turned to HEAT position, intake air heater mounting part does not become
warm.
Related
information
• Check that engine can be turned with starting motor (If engine cannot be turned, carry out trouble-
shooting for E-1 Engine does not start (Engine does not turn)).
Possible
causes and
standard value
in normal state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective heater relay
(Internal disconnec-
tion)
a
Prepare with starting switch OFF (with wiring harness connected), then
keep starting switch OFF and turn it to HEAT and carry out trouble-
shooting in each case.
Heater relay Starting switch Continuity/Resistance
Between T07 –
chassis ground
OFF There is continuity
Between T06 – T05 HEAT Max. 1
z
2
Defective intake air
heater (Internal discon-
nection)
a
Prepare with starting switch OFF (with wiring harness connected), then
turn starting switch to HEAT and carry out troubleshooting in each case.
E01 Starting switch Voltage
Between terminal –
chassis ground
HEAT 20 – 30 V
If voltage is normal but heater mounting part does not become warm,
intake air heater is defective.
3
Disconnection in wiring
harness (Disconnec-
tion in wiring or defec-
tive contact in
connector)
a
Prepare with starting switch OFF, then carry out troubleshooting without
turning starting switch ON.
Wiring harness between starting switch R1 –
heater relay T07
Resistance Max. 1
z
Wiring harness between battery relay M – heater
relay T06
Resistance Max. 1
z
Wiring harness between heater relay T05 – elec-
trical intake air heater E01
Resistance Max. 1
z