Preheater Does Not Operate - Komatsu PC130-8 Shop Manual

SEN04123-01
E-4 Preheater does not operate
Trouble (1) When starting switch is turned to HEAT position, preheating monitor does not light up or flash.
• 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).
Related • If engine coolant temperature is below 20°C, automatic warm-up system operates and preheating
information 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)
Defective starting switch
1
(Internal disconnection)
Possible causes
Disconnection in wiring har-
and standard
ness (Disconnection in wiring
value in normal
2
or defective contact in con-
state
nector)
3 Defective machine monitor
(2) When starting switch is turned to HEAT position, intake air heater mounting part does not become
Trouble
warm.
Related • Check that engine can be turned with starting motor (If engine cannot be turned, carry out trouble-
information shooting for E-1 Engine does not start (Engine does not turn)).
Defective heater relay (Inter-
1
nal disconnection)
Possible causes
and standard
Defective intake air heater
value in normal
2
(Internal disconnection)
state
Disconnection in wiring har-
ness (Disconnection in wiring
3
or defective contact in con-
nector)
14
Cause Standard value in normal state/Remarks on troubleshooting
a Prepare with starting switch OFF, then keep starting switch OFF
and turn it to HEAT and carry out troubleshooting in each case.
Between (1) – (3)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between CM01 (female)
(16) – J02 – H15 (female) (3)
a Prepare with starting switch OFF, then keep starting switch OFF
and turn it to HEAT and carry out troubleshooting in each case.
Between (16) –
chassis ground
Cause Standard value in normal state/Remarks on troubleshooting
a Prepare with starting switch OFF (with wiring harness con-
nected), then keep starting switch OFF and turn it to HEAT and
carry out troubleshooting in each case.
Between R17 –
chassis ground
Between R15 – R16
a Prepare with starting switch OFF (with wiring harness con-
nected), then turn starting switch to HEAT and carry out trou-
bleshooting in each case.
Between terminal –
chassis ground
If voltage is normal but heater mounting part does not become
warm, intake air heater is defective.
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between H15 (female) (3) –
J02 – heater relay R17
Wiring harness between battery relay R03A
– heater relay contact terminal (R15)
Wiring harness between heater relay R16 –
intake air heater M23
H15 (female) Starting switch
CM01 Starting switch
Heater relay Starting switch
M23 Starting switch
40 Troubleshooting
Resistance
OFF Min. 1 Mz
Max. 1 z
HEAT
Resis-
tance
Voltage
OFF Max. 1 V
HEAT 20 – 30 V
Continuity/Resis-
tance
OFF There is continuity
Max. 1 z
HEAT
Voltage
HEAT 20 – 30 V
Resis-
tance
Resis-
tance
Resis-
tance
1
Max. 1 z
Max. 1 z
Max. 1 z
Max. 1 z
PC130-8