Failure Code [Ddb6L4] Parking Brake Switch B: Disconnection/Hot Short - Komatsu WA250-6 Shop Manual

SEN03845-00

Failure code [DDB6L4] Parking brake switch B: Disconnection/Hot short

Action code Failure code
E03 DDB6L4
Contents of
• HST controller detected disagreement with parking brake signal from machine monitor.
trouble
(While signal was input to machine monitor (closed), signal was not input to HST controller (open).
• Turns the centralized warning lamp and alarm buzzer ON.
Action of • Stops neutralizer (parking brake drag prevention function).
controller
• If error is detected during forward or reverse travel, gear is set in neutral.
• Once FNR selector lever or switch is set to N, normal control is started again.
• If error is detected while FNR selector lever or switch is in F or R, machine cannot start until gear is
Problem that
returned to neutral.
appears on
• Since machine can travel forward and reverse while parking brake is applied, parking brake may be
machine
damaged (Caution buzzer sounds in this case, however).
• Parking brake switch A : For parking brake remind (Intermediate)
• Parking brake switch B : For parking brake indicator (Bottom)
• Operation of parking brake can be checked with monitoring function.
[Parking brake switch A] (Recognition by machine monitor)
Related
(Monitoring code: MONITOR PANEL – 40903 – D-IN-28 and 40904 – D-IN-35)
information
[Parking brake switch B] (Recognition by machine monitor)
(Monitoring code: MONITOR PANEL – 40903 – D-IN-26 and 40904 – D-IN-36)
[Parking brake switch A/B] (HST controller recognition)
(Monitoring code: HST – 99100 – PARKING A/B)
Defective diode
1
(Internal defect)
Disconnection in wiring har-
ness (Disconnection in wiring
2
or defective contact in con-
nector)
Ground fault in wiring har-
3 ness (Contact with GND cir-
cuit)
Possible causes
and standard
value in normal
state
Hot short (Contact with 24V
4
circuit) in wiring harness
5 Defective HST controller
6 Defective machine monitor
20
40-350
Failure code [DDB6L4] Parking brake switch B: Disconnection/Hot short
Parking brake switch B: Disconnection/Hot short
Trouble
(HST controller system)
Causes
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
(See Testing and adjusting, "Test procedure for diode".)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between HST (female) (16) –
L47 (female) (2)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
(Test with parking brake applied.)
Between wiring harness L27 (female) (1), (6)
– D02 (female) (7) and ground
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
Between wiring harness HST (female) (16) –
D02 (female) (5) and ground
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
(Test with parking brake released.)
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
(Test with parking brake released.)
350 Troubleshooting by failure code (Display of code), Part 5
Standard value in normal state/Remarks on troubleshooting
Between D02 (male) (5) – (1)
HST
Between (16) – ground
L27
Between (1) (6) – ground
Continuity is secured
Resis-
Max. 1 z
tance
Resis- Min.
tance 1 Mz
Voltage Max. 1 V
Voltage
Max. 1 V
Voltage
20 – 30 V
WA250, 250PZ-6