Komatsu PC200-8M0 Shop Manual page 836

SEN06138-00
Cause
Ground fault in wiring harness
8
(contact with ground circuit)
Failure 2) Automatic preheating does not function.
q
Automatic preheating starts when boost temperature is below -4 °C.
(Monitoring code Boost temperature: 18500)
q If automatic preheating does not function, check if manual preheating functions.
Related informa-
q
Engine controller checks primary (coil) side of preheater relay (connector R18) and generates fail-
tion
ure codes [CA2555] and [CA2556] if it is defective.
q
Engine controller checks boost temperature sensor and generates failure codes [CA153] and
[CA154] if it is defective.
Cause
Defective fuse No. 6 in fuse
1
box F01
Defective auto preheater
2 relay R18 (open or short cir-
cuit in internal wiring)
Open circuit or ground fault in
3
wiring harness
Open circuit in wiring har-
ness
4
(Wire breakage or defective
contact)
Ground fault in wiring har-
5 ness
(contact with ground circuit)
14
40-400
Procedure, measuring location, criteria and remarks
a If no failure is found by check on cause 3, this check is not required.
1. Turn starting switch to OFF position.
2. Disconnect connectors H15 and CM01, terminals R15 and E01, and
starting motor terminal B.
Between heater relay terminal R15 (wiring harness
side) and ground
Between input terminal on contact side of heater
relay and ground
Between heater relay terminal E01 (wiring harness
side) and ground
Procedure, measuring location, criteria and remarks
If fuse No. 6 in fuse box 01 is broken, circuit probably has ground fault. In this case,
perform troubleshooting for cause 5 first.
1. Turn starting switch to OFF position.
2. Replace auto preheater relay (connector R18) with horn relay (connector R08),
for example.
3. Turn starting switch to ON position.
If automatic preheater operates when charged (boosted) air temperature is below
-4 °C, original auto preheater relay is defective.
1. Turn starting switch to OFF position.
2. Disconnect connectors CM01 and R18, and connect T-adapter to female side of
R18.
a If resistance is above 1 Mz, wiring harness has open circuit. If resistance is be-
low 1 z, wiring harness has short circuit.
a Heater relay coil resistance
Between R18 (female) (5) and ground
1. Turn starting switch to OFF position.
2. Disconnect connectors R18 and CM01, and connect T-adapters to female side
of R18.
3. Remove fuse No. 6 in fuse box F01.
Between R18 (female) (3) and F01-6
Between R18 (female) (5) and heater relay terminal
R15
If fuse is not blown, this check is not required.
1. Turn starting switch to OFF position.
2. Disconnect connectors CM01, R18, and starting motor terminal B, and connect
T-adapter to female side of R18.
Between R18 (female) (3) and ground
400 Troubleshooting of electrical system (E-mode)
E-2 Preheater does not operate
Resistance Min. 1 Mz
Resistance Min. 1 Mz
Resistance Min. 1 Mz
Resistance Approx. 20 z
Resistance
Resistance
Resistance
PC200, 200LC, 220, 220LC-8M0
Max. 1 z
Max. 1 z
Min. 1 Mz