28 PC800, 850-8
SEN00791-02 40 Troubleshooting
Failure code [CA1631] BP Valve Pos Sens High Error
Action code Failure code
Trouble
BP Valve Pos Sens High Error
(Engine controller system)
E11 CA1631
Contents of
trouble
• Signal voltage in bypass valve lift sensor circuit is abnormally high.
Action of
controller
• Limits output and continues operation.
• Closes EGR valve and bypass valve.
Problem that
appears on
machine
• Output drops.
Related
information
• Signal voltage of bypass valve position sensor can be checked with monitoring function.
(Code: 18201 Bypass valve position sensor voltage)
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective sensor power
supply
If failure code [CA352] or [CA386] is displayed, carry out troubleshoot-
ing for it first.
2
Defective bypass valve lift
sensor (Internal trouble)
a Prepare with starting switch OFF, then turn starting switch ON or start
engine and carry out troubleshooting.
SBP Voltage
Between (1) – (2) Power supply 4.75 – 5.25 V
Sensor voltage is measured with wiring harness connected. Accord-
ingly, if voltage is abnormal, check wiring harness and controller, too, for
another cause of trouble, and then judge.
3
Disconnection in wiring
harness (Disconnection in
wiring or defective contact
in connector)
a Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) –
SBP (female) (1)
Resis-
tance
Max. 1 z
Wiring harness between ENG (female) (38) –
SBP (female) (2)
Resis-
tance
Max. 1 z
Wiring harness between ENG (female) (29) –
SBP (female) (3), (4)
Resis-
tance
Max. 1 z
4
Ground fault in wiring har-
ness (Short circuit with
GND circuit)
a Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) –
SBP (female) (1) and chassis ground
Resis-
tance
Min. 1 Mz
Wiring harness between ENG (female) (38) –
SBP (female) (2) and chassis ground
Resis-
tance
Min. 1 Mz
Wiring harness between ENG (female) (29) –
SBP (female) (3), (4) and chassis ground
Resis-
tance
Min. 1 Mz
5
Short circuit in wiring har-
ness (with another wiring
harness)
a Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Wiring harness between ENG (female) (37) –
SBP (female) (1) and between ENG (female)
(38) – SBP (female) (2)
Resis-
tance
Min. 1 Mz
Wiring harness between ENG (female) (37) –
SBP (female) (1) and between ENG (female)
(29) – SBP (female) (3), (4)
Resis-
tance
Min. 1 Mz
Wiring harness between ENG (female) (38) –
SBP (female) (2) and between ENG (female)
(29) – SBP (female) (3), (4)
Resis-
tance
Min. 1 Mz
6 Defective engine controller
a Prepare with starting switch OFF, then turn starting switch ON or start
engine and carry out troubleshooting.
ENG Voltage
Between (37) – (38) 4.75 – 5.25 V
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