Komatsu SAA6D114E-3 - Code [731;CA731] Eng. Bkup Speed Sensor Phase Error

SEN00460-01 40 Troubleshooting
34 114E-3 Series
E-45 Code [731/CA731] Eng. Bkup Speed Sensor Phase Error 1
Error code Failure code
Trouble Abnormality in engine Bkup speed sensor phase
731 CA731
Contents of
trouble
• Abnormal phase is detected in signals of engine Ne speed sensor and engine Bkup speed sensor.
Action of
controller
• Controls with signals of engine Ne speed sensor.
Problem that
appears
on machine
• Engine does not start or is difficult to start.
• Idle speed is unstable.
• Exhaust smoke is black.
Related infor-
mation
• Method of reproducing failure code: Start engine.
Possible
causes and
standard value
in normal state
Causes Standard value in normal state/Remarks on troubleshooting
1
Broken engine Ne speed
sensor
Inspect engine Ne speed sensor for breakage directly.
2
Broken engine Bkup speed
sensor
Inspect engine Bkup speed sensor for breakage directly.
3
Defective or broken mount of
rotation sensing ring on
crankshaft side
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 center of speed sensor ring notch is at end of Ne speed sensor,
speed sensor ring is installed normally.
4
Defective or broken mount of
rotation sensing ring on cam-
shaft side
Inspect rotation sensing gear for defect or breakage according to
the following procedure.
1) Set No. 1 cylinder to compression top dead center (align stamp-
ing mark).
2) Remove Bkup speed sensor.
3) If groove of rotation sensing gear side can be seen through sen-
sor mounting hole, it is mounted normally.
5
Defective timing between
crankshaft and camshaft
Inspect crankshaft and camshaft for timing directly.
6
Defective connection of
ground terminal
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