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CHAPTER 2 TROUBLESHOOTING FOR CONTROL CIRCUITS
CHAPTER 2 TROUBLESHOOTING FOR CONTROL CIRCUITS
3. 3.23
23 Ac
Acce cele lera rato tor Sen
Error code: 51
Error code: 51
Situation
Situation
Possible
Possible
cause
cause
Trigger of
Trigger of
the error
the error
code
code
Checks
Checks
(1) Raise front wheels until they clear floor
(1) Raise front wheels until they clear floor
(2) Disconnect battery plug
(2) Disconnect battery plug
(3) Check link length of accelerator pedal
(3) Check link length of accelerator pedal
(4) Perform inverter discharging work
(4) Perform inverter discharging work
(6)
(6) D
Disco
isconnect con
(7) Check continuity between E-02-20 and E-19-6(52)
(7) Check continuity between E-02-20 and E-19-6(52)
Check
Check
(Sensor voltage)
(Sensor voltage)
(8) Check continuity between E-02-24 and E-19-3(55)
(8) Check continuity between E-02-24 and E-19-3(55)
Check continuity between E-02-23(54) and E-19-5(54)
Check continuity between E-02-23(54) and E-19-5(54)
Without
Without
service tool
service tool
(10) Replace accelerator pedal
(10) Replace accelerator pedal
(11) Disconnect battery plug
(11) Disconnect battery plug
(12) Reinstall accelerator pedal, then replace logic card of
(12) Reinstall accelerator pedal, then replace logic card of
logic unit
logic unit
(13) C
(13)
Connect connector E
onnect connector
(14) Turn off power. Short-circuit E-19-3(55) and
(14) Turn off power. Short-circuit E-19-3(55) and
E-19-
E-19-
Turn on power and check accelerator voltage with service tool
Turn on power and check accelerator voltage with service tool
(15) Turn off power
(15) Turn off power
3
3
6
6
H-01(3W)
H-01(3W)
r Senso
sor Fau
r Fault (5
lt (51) 1)
Display: "51". All
Display: "51". All truck operations inhibited. Line contactor HOLD and ST contactor HOLD.
truck operations inhibited. Line contactor HOLD and ST contactor HOLD.
Traction motor and pump mo
Traction moto
r and pump motor operation
operations inhibited except mast lowering operation.
operations inhibited except mast lowering operation.
Improper accelerator pedal linkage, faulty
Improper accelerato
r pedal linkage, faulty accelerator sensor, faulty main harness, faulty logic unit.
Sensor 1 or 2 output is 0.2 V or lower, or 4.8 V or higher.
Sensor 1 or 2 output is 0.2 V or lower, or 4.8
Difference in output between sensors 1 and 2 is
Difference in output betwe
Normal
Normal
Abnormal
Abnormal
nnect
connectors
nectors
E-19
E-19
and E-
and
E-02
02
continuit
continuit
y between
y between
E
E
-02-21
-02-21
and E-19-2(53)
and E-19-2(53)
Continuity
Continuity
No
No
continuity
continuity
Continuity
Continuity
No
No
continuity
continuity
With service tool
With service tool
If fault remains
If fault remains
E-19
-19
and E-02
and E-02
Turn on power
Turn on power
5
5
V
V
6(52), E-19-
6(52)
,
E-19-2(53)
2(53)
5
5
V
V
B
B
23
23
1
1
2
2
1
1
1
1
2
2
3
3
5
5
4
4
4
4
5
5
6
6
E-38(4W)
E-38(4W)
tor operation inhibited. If this fault o
inhibited. If this fault occurs before S
accelerator sensor, faulty main harness, faulty logic unit.
V or higher.
en sensors 1 and 2 is 0.5 V or more.
0.5 V or more.
(5) Adjust accelerator pedal linkage
(5) Adjust accelerator pedal linkage
of logic unit
of logic unit
(9) Repair or replace harness
(9) Repair or replace harness
and
and
check
check
voltage between E-19-3(55)
voltage between E-19-3(55)
Not
Not
5
5
V
V
1
1
2
2
E-27
E-27
ccurs before ST contactor CLO
T contactor CLOSE, all
and E-19-5(54)
and E-19-5(54)
Not
Not
5
5
V
V
501145
501145
2-57
2-57
SE, all
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