Failure Code [Ca778] Eng Bkup Speed Sensor Error - Komatsu PC210-8 Shop Manual

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Failure code [CA778] Eng Bkup Speed Sensor Error

Failure code

• There is error in signal from engine Bkup speed sensor.

• Continues control with signal from engine Ne speed sensor.

Problem that

• Engine does not start easily.

• Engine output lowers.

Related infor-

• Method of reproducing failure code: Start engine.

Defective sensor power sup-

ply 2 system

Defective engine Bkup

speed sensor

Breakage or improper clear-

ance of engine Bkup speed

Breakage of rotation sensor

Disconnection in wiring har-

ness (Disconnection in wiring

Possible causes

or defective contact in con-

and standard

value in normal

Ground fault in wiring har-

ness (Short circuit with GND

Hot short (Short circuit with

5V/24V circuit) in wiring har-

Short circuit in wiring har-

ness (with another wiring

Engine Bkup speed sensor error

(Engine controller system)

Standard value in normal state/Remarks on troubleshooting

If failure code [CA187] is also displayed, carry out troubleshooting

for it first.

a Prepare with starting switch OFF, then turn starting switch ON

and carry out troubleshooting.

Between (1) – (2)

Voltage is measured with wiring harness connected. Accordingly, if

voltage is abnormal, check wiring harness and controller, too, for

another cause of trouble, and then judge.

Engine Bkup speed sensor may be broken or may have improper

clearance. Check it directly.

Rotation sensor ring may be broken. Check it directly.

a Prepare with starting switch OFF, then carry out troubleshooting

without turning starting switch ON.