Failure Code [Ca778] Eng. Bkup Speed Sensor Error - Komatsu Galeo PC138US-8 Shop Manual

SEN02464-01

Failure code [CA778] Eng. Bkup speed sensor error

User code Failure code
E15
Contents of
• Abnormality occurred in engine Bkup speed sensor circuit.
trouble
Action of
• Operates with signals of Ne speed sensor.
controller
Problem that
• Running engine stops (when Ne speed sensor is also abnormal).
appears on
• Stopped engine cannot be started (when Ne speed sensor is also abnormal).
machine
Related
• Method of reproducing failure code: Start engine.
information
Defective sensor power sup-
1
ply system
Disconnection in wiring har-
ness
2 (Disconnection in wiring or
defective contact in connec-
tor)
Ground fault in wiring har-
ness
3
(Short circuit with GND cir-
cuit)
Possible causes
and standard
value in normal
state
Short circuit in wiring har-
ness
4
(With another wiring har-
ness)
Defective mount of sensor or
5 defective rotation sensing
part
Defective engine Bkup
6
speed sensor
7 Defective engine controller
24
Trouble
CA778
Causes
Eng. Bkup speed sensor error
(Engine controller system)
Standard value in normal state/Remarks on troubleshooting
If failure code [CA187] or [CA227] is indicated, carry out trouble-
shooting for it first.
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between CE01 (female) (36)
– CAM (female) (1)
Wiring harness between CE01 (female) (48)
– CAM (female) (2)
Wiring harness between CE01 (female) (37)
– CAM (female) (3)
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between CE01 (female) (36)
– CAM (female) (1) and chassis ground
Wiring harness between CE01 (female) (48)
– CAM (female) (2) and chassis ground
Wiring harness between CE01 (female) (37)
– CAM (female) (3) and chassis ground
a Prepare with starting switch OFF, then carry out troubleshoot-
ing without turning starting switch ON.
Wiring harness between CE01 (female) (36)
– CAM (female) (1) and between CE01
(female) (48) – CAM (female) (2)
Wiring harness between CE01 (female) (36)
– CAM (female) (1) and between CE01
(female) (37) – CAM (female) (3)
Wiring harness between CE01 (female) (48)
– CAM (female) (2) and between CE01
(female) (37) – CAM (female) (3)
Check Bkup speed sensor directly for defective mount (defective
clearance) or check rotation sensing part (in supply pump) directly
for defect.
If causes 1 – 5 are not detected, engine Bkup speed sensor may
be defective. (Since trouble is in system, troubleshooting cannot be
carried out.)
If causes 1 – 6 are not detected, engine controller may be defec-
tive. (Since trouble is in system, troubleshooting cannot be carried
out.)
40 Troubleshooting
1
Resis-
Max. 1 z
tance
Resis-
Max. 1 z
tance
Resis-
Max. 1 z
tance
Resis-
Min.1 Mz
tance
Resis-
Min.1 Mz
tance
Resis-
Min.1 Mz
tance
Resis-
Min.1 Mz
tance
Resis-
Min.1 Mz
tance
Resis-
Min.1 Mz
tance
PC138US, USLC-8