Code [757/Ca757] All Engine Controller Data Lost Error - Komatsu 114E-3 Series Shop Manual

SEN00460-01
E-46 Code [757/CA757] All Engine Controller Data Lost Error
Error code Failure code
757
Contents of
• All data in engine controller are lost.
trouble
Action of con-
• None in particular.
troller
Problem that
• Engine stops and sometimes cannot be started.
appears on
• Monitoring function of machine monitor (engine controller system) may not work normally.
machine
Related infor-
• Method of reproducing failure code: Starting switch ON.
mation
1 Defective related system
Loose or corroded battery
2
terminal
3 Defective battery voltage
4 Defective fuse No. 19
Defective relay for engine
5
controller power supply
Possible causes
and standard
value in normal
state
Disconnection in wiring har-
ness (Disconnection in wiring
6
or defective contact in con-
nector)
Defective wiring harness
7
connector
8 Defective engine controller
36
Trouble
CA757
Causes
Loss of all data in engine controller
Standard value in normal state/Remarks on troubleshooting
If another failure code is indicated, carry out troubleshooting for it.
Inspect battery terminal directly for loose and corrosion.
a Prepare with starting switch OFF, then turn starting switch OFF
and START and carry out troubleshooting.
Battery (1 piece)
Between (+) – (–)
terminals
If fuse is burnt out, circuit probably has ground fault.
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
Replace relays for engine controller power supply (R23, R24) with
other relays. If mark E of failure code disappears after reproduction
operation is conducted, that relay has a defect.
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between F01-19 – R23, R24
(female) (3)
Wiring harness between R23, R24 (female)
(5) – J3 (female) (3)
Wiring harness between J3 (female) (1) –
chassis ground (T12)
Connecting parts among fuse No. 19, engine unit wiring harness,
and engine controller are suspected. Inspect them directly.
• Loose connector, broken lock, broken seal
• Corrosive, bent, broken, forced-in, or extended pin
• Humidity in connector, entry of dirt or dust, poor insulation
a Prepare with starting switch OFF, then turn starting switch ON
and START and carry out troubleshooting.
J3 (female)
Between (3) – (1)
40 Troubleshooting
Starting switch
OFF Min. 12 V
START Min. 6.2 V
Resis-
tance
Resis-
tance
Resis-
tance
Starting switch
ON Min. 24 V
START Min. 12 V
114E-3 Series
1
Voltage
Max. 10 z
Max. 10 z
Max. 10 z
Voltage