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Fault code
Meaning of the fault code
(Hex)
possible reason for fault detection
7F
O.C. at engine derating device
TCU detected a wrong voltage at the
output pin, that looks like a O.C. for this
output pin
Cable is defective and has no
connection to TCU
Engine derating device has an internal
defect
Connector has no connection to TCU
85
S.C. to ground at clutch KV
The measured resistance value of the valve
is out of limit, the voltage at K4 valve is too
low
Cable/connector is defective and has
contact to vehicle ground
Regulator has an internal defect
86
O.C. at clutch KV
The measured resistance value of the
valve is out of limit
Cable/connector is defective and has
contact to TCU
Regulator has an internal defect
87
S.C. to battery voltage at clutch KR
The measured resistance value of the
valve is out of limit, the voltage at KR valve is
too high
Cable/connector is defective and has
contact to battery voltage
Cable/connector is defective and has
contact to another regulator output of the
TCU
Regulator has an internal defect
Reaction of the TCU
No reaction
OP mode : Normal
TCU shifts to neutral
OP mode : Limp home
If failure at another clutch is
pending
TCU shifts to neutral
OP mode : TCU shutdown
TCU shifts to neutral
OP mode : Limp home
If failure at another clutch is
pending
TCU shifts to neutral
OP mode : TCU shutdown
TCU shifts to neutral
OP mode : Limp home
If failure at another clutch is
pending
TCU shifts to neutral
OP mode : TCU shutdown
3-23
Possible steps to repair
Check the cable from TCU to the
engine derating device
Check the connectors from engine
derating device to TCU
Check the resistance* of engine
derating device
* See page 3-36
Check the cable from TCU to the
gearbox
Check the connectors from
gearbox to TCU
Check the regulator resistance*
Check internal wire harness of the
gearbox
* See page 3-36
Check the cable from TCU to the
gearbox
Check the connectors from
gearbox to TCU
Check the regulator resistance*
Check internal wire harness of the
gearbox
* See page 3-36
Check the cable from TCU to the
gearbox
Check the connectors from
gearbox to TCU
Check the regulator resistance*
Check internal wire harness of the
gearbox
* See page 3-36
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