Failure Code [Ca731] Eng Bkup Speed Sens Phase Error - Komatsu PC200-8M0 Shop Manual

SEN06134-00

Failure code [CA731] Eng Bkup Speed Sens Phase Error

Action
Failure code
level
L01 CA731
q
Phase error is detected between signals from engine Ne speed sensor and engine Bkup speed
Detail of failure
sensor
Action of con-
q Continues to control engine by using signal from engine Ne speed sensor.
troller
q
Engine does not start at all or does not start easily.
Problem on
q
Idle speed is unstable.
machine
q
Exhaust gas becomes black.
Related infor-
q
Method of reproducing failure code: Start engine.
mation
Cause
Breakage of engine Ne speed sen-
1
sor
Breakage of engine Bkup speed
2
sensor
Defective installation or breakage
3 of speed sensing wheel on crank-
shaft side
Defective installation or breakage
4 of speed sensing ring on camshaft
side
Defective timing of crankshaft and
5
camshaft
Defective connection of ground
6
terminal
42
40-302

Failure code [CA731] Eng Bkup Speed Sens Phase Error

Engine Bkup Speed Sensor Phase Error
Failure
(Engine controller system)
Procedure, measuring location, criteria and remarks
Engine Ne speed sensor may be broken. Check it.
Engine Bkup speed sensor may be broken. Check it.
Speed sensing wheel on crankshaft side may be installed defectively or bro-
ken. Check it according to following procedure.
1. Align paint mark (M1) on damper with Ne speed sensor top (M2).
a Do not align with mark of No. 1 cylinder compression top dead center
(approimately 80 deg. before compression top dead center).
2. If center of oblong hole (WS) of speed sensing wheel aligns with Ne speed
sensor top (M2), installation is correct.
Speed sensing ring on camshaft may be installed defectively or broken. Check
it according to the following procedure.
1. Set No. 1 cylinder to compression TDC (align with mark).
2. Remove Bkup speed sensor.
3. If you can see double-slot part (with one crest) (B) on speed sensing ring
through sensor mounting hole (H), speed sensing ring is installed correctly.
Timing of crankshaft and camshaft may be defective. Check it.
Connection of ground terminal may be defective. Check following terminals.
q
Ground terminal of machine ((-) terminal of battery)
q
Ground terminal of engine
q Ground terminal of engine controller
q
Ground terminal of starting motor
302 Troubleshooting by failure code, Part 2
PC200, 200LC, 220, 220LC-8M0