Failure Code [Ca731] Engine Bkup Speed Sensor Phase Error - Komatsu WA250-6 Shop Manual

SEN03843-00

Failure code [CA731] Engine Bkup speed sensor phase error

Action code Failure code
E03
Contents of
• Abnormal phase is detected in signals of engine Ne speed sensor and engine Bkup speed sensor.
trouble
Action of • Controls Ne speed sensor with signals of Bkup speed sensor.
controller
• Turns the centralized warning lamp and alarm buzzer ON.
• Engine does not start or is difficult to start.
Problem that
appears on
• Idle speed is unstable.
machine
• Exhaust smoke is black.
Related
• Method of reproducing failure code: Start engine
information
Broken engine Ne speed
1
sensor
Broken engine Bkup speed
2
sensor
Defective/broken mount of
3 rotation sensing flywheel on
crankshaft side
Possible causes
and standard
value in normal
Defective/broken mount of
state
4 rotation sensing ring on cam-
shaft side
Defective timing between
5
crankshaft and camshaft
Defective connection of
6
ground terminal
34
40-330
Trouble
CA731
Causes
330 Troubleshooting by failure code (Display of code), Part 3
Failure code [CA731] Engine Bkup speed sensor phase error
Engine Bkup speed sensor phase error
(Engine controller system)
Standard value in normal state/Remarks on troubleshooting
Inspect engine Ne speed sensor for breakage directly.
Inspect engine Bkup speed sensor for breakage directly.
Inspect it for defect or breakage according to the following proce-
dure.
1) Set No. 1 cylinder to compression top dead center (align stamp-
ing mark).
2) If tip of Ne speed sensor is aligned with center of oblong hole of
rotation sensing flywheel, it is mounted normally.
Inspect it for defect or breakage according to the following proce-
dure.
1) Set No. 1 cylinder to compression top dead center (align stamp-
ing mark).
2) Remove Bkup speed sensor.
3) If 2 grooves (1 thread) of rotation sensing ring can be seen
through sensor mounting hole, it is mounted normally.
Inspect crankshaft and camshaft for timing directly.
Inspect following directly for connection of ground terminal.
• Ground terminal (battery (-)) of machine main unit.
• Ground terminal of engine
• Ground terminal of engine controller
• Ground terminal of starting motor
1
WA250, 250PZ-6