Preheater Does Not Operate - Komatsu PC200-8M0 Shop Manual

400 Troubleshooting of electrical system (E-mode)
E-2 Preheater does not operate
E-2 Preheater does not operate
Failure 1) Manual preheating does not function.
a This troubleshooting describes procedures to be followed when manual preheating does not
q
Related information
q
q
Cause
Defective fuse No. 17 in fuse box
1
F01
Loose terminal or open circuit at
2
terminal
Open circuit or ground fault in wir-
3
ing harness
Defective heater relay
4
(Does not work) (Terminal R16)
Defective diode D02
5
(internal open or short circuit)
Defective electrical intake air
6 heater (ribbon heater)
(Internal open circuit)
7 Defective starting switch
PC200, 200LC, 220, 220LC-8M0
function to heat electrical intake air heater (ribbon heater) mounting section.
"Automatic preheating" and "Manual preheating" functions are available. When either function
is operated, preheating monitor lights up. (When only preheating monitor does not light up,
perform troubleshooting "3) While preheater is operating, preheating monitor does not light
up")
If "Machine monitor displays nothing" or "Battery relay operation sound is not heard" when
turning starting switch to ON position, main electric power supply system may be defective.
So, perform troubleshooting for E-3 and E-1.
Before performing troubleshooting, check that no related failure code is displayed.
(If failure codes [D110KB] is displayed, troubleshoot it first.)
If fuse No. 17 in fuse box F01 is broken, circuit probably has ground fault. In
this case, perform troubleshooting for cause 8 first.
1. Turn starting switch to OFF position.
Check terminals of heater relay, battery relay, electrical intake air heater (rib-
bon heater), etc.
1. Turn starting switch to OFF position.
2. Disconnect connectors CM01 and H15, and connect T-adapter to female
side of H15.
a Heater relay coil resistance
Between H15 (female) (3) and ground
1. Turn starting switch to OFF position.
2. Turn starting switch to ON position.
Between input terminal on contact side of heater
relay and ground
1. Turn starting switch to OFF position.
2. Disconnect heater relay terminal R16.
a To prevent current from flowing through heater when starting switch is
turned to HEAT position
3. Turn starting switch to HEAT position (Connect R1).
Between heater relay terminal R15 and ground
If no failure is found by check on cause 3 and heater relay operation sound is
not heard, heater relay is defective.
1. Turn starting switch to OFF position.
2. Disconnect connector D02 and connect T-adapters to diode.
a Check by using multimeter in diode range.
Between D02 (male) (1) (+) and (5) (-)
Between D02 (male) (5) (+) and (1) (-)
1. Turn starting switch to OFF position.
2. Disconnect terminal E01.
Between E01 terminal and ground
1. Turn starting switch to OFF position.
2. Disconnect battery ground cable.
3. Disconnect connector H15 and connect T-adapters to male side.
4. Turn starting switch to OFF/HEAT position and perform troubleshooting.
Between H15 (male) (1) and (3)
Procedure, measuring location, criteria and remarks
SEN06138-00
Approx.
Resistance
Voltage 20 to 30 V
Voltage 20 to 30 V
No continuity
Continuity
Continuity
OFF Resistance Min. 1 Mz
HEAT Resistance Min. 1 Mz
40-400
20 z
13