Troubleshooting Of Electrical System (E-Mode); Power Ladder Does Not Operate - Komatsu WA900-3E0 Shop Manual

Troubleshooting of electrical system (E-mode)

E-1 Power ladder does not operate
q
Failure
q
q
q
Related information
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No. Cause
Open circuit in wiring harness
1 (wire breakage or defective con-
tact of connector)
Defective upper power ladder
2 switch
(internal short circuit)
Defective lower power ladder
3 switch
(internal short circuit)
Open circuit in wiring harness
4 (wire breakage or defective con-
tact of connector)
WA900-3E0
When ladder RAISE or LOWER switch is operated, ladder does not move.
If failure code related to power ladder appears, see troubleshooting for failurer code.
If emergency release valve is open, ladder cannot be moved to storage or boarding position
by operating switches.
If load of 15kg or heavier is on bottom step of ladder, pump stalls and ladder does not rise.
Input signal from ladder RAISE switch can be checked with monitoring function.
Code: 40989 "D-IN-0" (ON: 1, OFF: 0)
Input signal from ladder LOWER switch can be checked with monitoring function.
Code: 40989 "D-IN-1" (ON: 1, OFF: 0)
1. Turn starting switch to OFF position.
2. Disconnect PC0, LS2, and PLS1.
3. Turn starting switch to ON position, and then perform troubleshooting.
Resistance
1. Turn starting switch to OFF position.
2. Disconnect LS2.
Resistance
1. Turn starting switch to OFF position.
2. Disconnect PLS1.
Resistance
1. Turn starting switch to OFF position.
2. Disconnect PL11, LS2, and PLS1.
3. Turn starting switch to ON position, and then perform troubleshooting.
Resistance

Troubleshooting of electrical system (E-mode)

Procedure, measuring location, criteria and remarks
Between PC0 (34) and PLS1 (2)
Between PC0 (34) and PLS2 (2)
Between PC0 (5) and PLS1 (2)
Between PC0 (5) and PLS2 (2)
Between LS2 (female) (3) and LS2
(female) (2)
Between LS2 (female) (3) and LS2
(female) (1)
Between LS2 (female) (4) and LS2
(female) (5)
Between LS2 (female) (4) and LS2
(female) (6)
Between PLS1 (female) (3) and PLS1
(female) (2)
Between PLS1 (female) (3) and PLS1
(female) (1)
Between PLS1 (female) (4) and PLS1
(female) (5)
Between PLS1 (female) (4) and PLS1
(female) (6)
Between PL11 (1) and PLS1 (1)
Between PL11 (1) and PLS1 (6)
Between PL11 (1) and PLS2 (1)
Between PL11 (1) and PLS2 (6)
Between PL11 (2) and ground
E-1 Power ladder does not operate
Max. 1 z
Max. 1 z
Max. 1 z
Max. 1 z
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Switch: ON
Max. 1 z
Max. 1 z
Max. 1 z
Max. 1 z
Max. 1 z
4 0 - 5 3
4 0 - 5 3
40-53