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CHAPTER 2 TROUBLESHOOTING FOR CONTROL CIRCUITS
CHAPTER 2 TROUBLESHOOTING FOR CONTROL CIRCUITS
3.47 7 Hyd
3.4
Hydrau
Error code: 74
Error code: 74
Situation
Situation
Possible
Possible
cause
cause
Trigger of
Trigger of
the error
the error
code
code
Checks
Checks
(1) Disconnect battery plug, then perform inverter discharging work
(1) Disconnect battery plug, then perform inverter discharging work
(2)
(2) D
Disconnect connec
isconnect
Disconnect connector E-13 of lift lock valve
Disconnect connector E-13 of lift lock valve
(3)
(3) Chec
Check short circu
(4) Repair or replace main harness
(4) Repair or replace main harness
raulic
lic Loc
Lock So
k Solen
lenoid
oid Fau
Fault lt (74
Display: "74".
Display: "74". Pump motor operatio
Pump motor operation inhibited. Normal traction motor operatio
operation.
operation.
Faulty lift lock valve, faulty main harness, faulty logic unit.
Faulty lift lock valve, faulty main harness, faulty logic unit.
By short circuit detection signal of logic card.
By short circuit detection signal of
connector E-04 of logic
tor E-04 of logic
unit
unit
k short
circuit
it
between
between
E-13-1
E-1
3-1
and E-13-2 of harness
and E-13-2 of harness sid
Shorted
Shorted
(74) )
n inhibited. Normal traction motor operation and power steering
logic card.
side
e
(5)
(5) C
Check s
heck
short circ
hort
valve side connectors
valve side connectors
Measure coil resistance
Measure coil resistance
[7.9 Ω at
[7.9 Ω at -
-30 °C
30 °C
[22.1 Ω at -30 °C
[22.1 Ω at -30 °C
Normal
Normal
(6) Replace logic card of
(6) Replace logic card of
log
logic
ic
unit
un
it
n and power steering
Not shorted
Not shorted
circuit between
uit between
E-13-1 and
E-13-1 and E
E-13-
-13-2
(-22 °F)
(-22 °F)
to
to
11.8
11.8
Ω at 80 °C
Ω at 80 °C (
(176 °F
176
(-22 °F) to
(-22 °F) to
37.6 Ω at 80 °C (
37.6 Ω at 80 °C
Abnormal
Abnormal
(7) R
(7)
Replace lift lock
eplace lift lock
501154
501154
2-107
2-107
2
lift
lift
lock
lock
°F)]
)]
(MC)
(MC)
(176 °F
176
°F)]
)]
(FC)
(FC)
valve
valve
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