Komatsu PC200-8M0, Shop Manual

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303 Troubleshooting by failure code, Part 3
Failure code [DGH2KB] Hyd Oil Sensor Short Circuit
40-303
40
PC200, 200LC, 220, 220LC-8M0
SEN06135-00
Failure code [DGH2KB] Hyd Oil Sensor Short Circuit
Action
level
Failure code
Failure
Hydraulic Oil Sensor Short Circuit
(Pump controller system)
L01 DGH2KB
Detail of failure
q
Signal voltage of hydraulic oil temperature sensor circuit is below 1 V, so pump controller deter-
mines that circuit shorts.
Action of con-
troller
q
If cause of failure disappears, machine becomes normal by itself.
Problem on
machine
q
Regardless of the hydraulic oil temperature, hydraulic oil temperature gauge meter is equivalent to
50 degrees.
Related infor-
mation
q
Signal voltage from hydraulic oil temperature sensor can be checked with monitoring function.
(Code: 04402: Hydraulic oil temperature sensor voltage)
q
Method of reproducing failure code: Start engine.
Cause Procedure, measuring location, criteria and remarks
1
Defective hydraulic oil tempera-
ture sensor
(internal open or short circuit)
1. Turn starting switch to OFF position.
2. Disconnect connector P22 and connect T-adapters to male side.
Between P22 (male) (1)
and (2)
a
Temperature-Resis-
tance characteristics of
oil temperature sensor
10 °C Resistance Approx. 90 k
z
30 °C Resistance Approx. 35 k
z
80 °C Resistance Approx. 6.5 k
z
100 °C Resistance Approx. 3.5 k
z
Between P22 (male) (2) and ground Resistance Min. 1 M
z
2
Open circuit or short circuit or
ground fault or hot short circuit in
wiring harness
1. Turn starting switch to OFF position.
2. Disconnect connector P22 and connect T-adapters to female side.
3. Turn starting switch to ON position.
a
If voltage is 0 V, wiring harness has open circuit, ground fault, or short cir-
cuit, and if voltage is 24 V, wiring harness has hot short circuit.
a
Voltage of about 5 V is applied to temperature sensor signal lines through
resistor in pump controller.
Between P22 (female) (1) and (2) Voltage Approx. 5 V
3
Short circuit or ground fault in wir-
ing harness
1. Turn starting switch to OFF position.
2. Disconnect connector C01 and connect T-adapters to female side.
a
Use Temperature-Resistance characteristics table for troubleshooting on
cause 1 as resistance criteria.
a
If resistance is above 1 M
z
, wiring harness has open circuit. If resistance
is below 1
z
, wiring harness has short circuit.
Between C01 (female) (29) and (46) Resistance 3.5 to 90 k
z
Between C01 (female) (29) and ground Resistance Min. 1 M
z
4
Ground fault in wiring harness
(contact with ground circuit)
a
If no failure is found by check on cause 2, this check is not required.
1. Turn starting switch to OFF position.
2. Disconnect connectors C01 and P22, and connect T-adapters to either
female side.
Between C01 (female) (29) and ground, or
between P22 (female) (2) and ground
Resistance Min. 1 M
z
5 Defective pump controller
If no failure is found by above checks, pump controller is defective. (Since this
is an internal defect, troubleshooting cannot be performed.)