Komatsu PC130-8 User Manual

SEN04120-03 40 Troubleshooting
26 PC130-8
Failure code [CA778] Eng. Bkup speed sensor error 1
User code Failure code
Trouble
Eng. Bkup speed sensor error
(Engine controller system)
E15 CA778
Contents of
trouble
• Abnormality occurred in engine Bkup speed sensor circuit.
Action of
controller
• Operates with signals of Ne speed sensor.
Problem that
appears on
machine
• Running engine stops (when Ne speed sensor is also abnormal).
• Stopped engine cannot be started (when Ne speed sensor is also abnormal).
Related
information
• Method of reproducing failure code: Start engine.
Possible causes
and standard
value in normal
state
Causes Standard value in normal state/Remarks on troubleshooting
1
Defective sensor power sup-
ply system
If failure code [CA187] or [CA227] is indicated, carry out trouble-
shooting for it first.
2
Disconnection in wiring har-
ness
(Disconnection in wiring or
defective contact in connec-
tor)
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between ENG1 (female)
(36) – CAM (female) (3)
Resis-
tance
Max. 1 z
Wiring harness between ENG1 (female)
(48) – CAM (female) (2)
Resis-
tance
Max. 1 z
Wiring harness between ENG1 (female)
(37) – CAM (female) (1)
Resis-
tance
Max. 1 z
3
Ground fault in wiring har-
ness
(Short circuit with GND cir-
cuit)
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between ENG1 (female)
(36) – CAM (female) (3) and chassis ground
Resis-
tance
Min.1 Mz
Wiring harness between ENG1 (female)
(48) – CAM (female) (2) and chassis ground
Resis-
tance
Min.1 Mz
Wiring harness between ENG1 (female)
(37) – CAM (female) (1) and chassis ground
Resis-
tance
Min.1 Mz
4
Short circuit in wiring har-
ness
(With another wiring har-
ness)
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between ENG1 (female)
(36) – CAM (female) (3) and between ENG1
(female) (48) – CAM (female) (2)
Resis-
tance
Min.1 Mz
Wiring harness between ENG1 (female)
(36) – CAM (female) (3) and between ENG1
(female) (37) – CAM (female) (1)
Resis-
t
ance
Min.1 Mz
Wiring harness between ENG1 (female)
(48) – CAM (female) (2) and between ENG1
(female) (37) – CAM (female) (1)
Resis-
tance
Min.1 Mz
5
Defective mount of sensor or
defective rotation sensing
part
Check Bkup speed sensor directly for defective mount (defective
clearance) or check rotation sensing part (in supply pump) directly
for defect.
6
Defective engine Bkup
speed sensor
If causes 1 – 5 are not detected, engine Bkup speed sensor may
be defective. (Since trouble is in system, troubleshooting cannot be
carried out.)
7 Defective engine controller
If causes 1 – 6 are not detected, engine controller may be defec-
tive. (Since trouble is in system, troubleshooting cannot be carried
out.)

Komatsu PC130-8 Specifications

General

Brand	Komatsu
Model	PC130-8
Category	Excavators
Language	English