Failure Code [Ca778] Eng Bkup Speed Sensor Error - Komatsu Galeo PC800-8 Shop Manual

SEN00791-02

Failure code [CA778] Eng Bkup Speed Sensor Error

Action code Failure code
E15 CA778
Contents of
• There is error in engine Bkup speed sensor circuit.
trouble
Action of
• Operates the engine with signal from engine Ne speed sensor.
controller
Problem that
• Engine stops during operations. (When engine Ne speed sensor is also defective)
appears on
• Engine cannot be started while stopping. (When engine Ne speed sensor is also defective)
machine
Related
information
Defective sensor power
1
supply 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-
4 ness
(with another wiring harness)
Defective sensor installa-
5 tion or defective rotation
sensor parts
Defective engine Bkup
6
speed sensor
7 Defective engine controller
18
Engine Bkup speed sensor error
Trouble
(Engine controller system)
Cause
If failure code [CA187] or [CA227] is displayed, carry out troubleshoot-
ing for it first.
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) – G
(female) (1)
Wiring harness between ENG (female) (47) – G
(female) (2)
Wiring harness between ENG (female) (26) – G
(female) (3)
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) – G
(female) (1) and chassis ground
Wiring harness between ENG (female) (47) – G
(female) (2) and chassis ground
Wiring harness between ENG (female) (26) – G
(female) (3) and chassis ground
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) – G
(female) (1) and between ENG (female) (47) –
G (female) (2)
Wiring harness between ENG (female) (37) – G
(female) (1) and between ENG (female) (26) –
G (female) (3)
Wiring harness between ENG (female) (47) – G
(female) (2) and between ENG (female) (26) –
G (female) (3)
Bkup speed sensor may be installed defectively (improper clearance),
or rotation sensor parts (in supply pump) may be defective. Check them
directly.
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 defective.
(Since trouble is in system, troubleshooting cannot be carried out.)
Standard value in normal state/Remarks on troubleshooting
40 Troubleshooting
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
PC800, 850-8