TM 5-3805-281-24-1
Diagnostic Information
DIAGNOSE ELECTRONIC AND CONTROL
VALVE COMPONENT MALFUNCTIONS
Part Name
Engine Control Motor (EC Motor)
Engine Control Sensor (EC
Engine rpm Dial
Sensor)
Operational Function
Move fuel injection pump lever.
Senses position of EC motor
Signal to engine and pump
controller to set target engine
speed for injection pump lever
position.
Control Problem
Fuel injection pump lever does not
Loss of EC motor position sensing.
Speed does not change when dial
move
Whenever key switch is ON,
is turned.
injection pump lever position is
learned as the slow idle speed
position. Accordingly, engine speed
is controlled afterward from the
learned position which occurred at
this time.
Machine Symptoms
Turning engine rpm dial does not
Engine speeds slower or faster than
Speed is held at 1600 rpm.
increase or decrease engine speed.
speed selected by engine rpm dial
(Auto-idle function operates and
and E mode switch. Cannot control
engine stops by turning key switch
speed.
off.)
Laptop Computer
--
01 Service code is displayed
07 Service code is displayed.
Self-Diagnostic Function
Laptop Computer
--
Monitor No. 2, EC angle. Typical
Monitor No. 13, Target Engine
Monitoring Function
voltage for slow idle is 2.5 volts.
Speed.
Harness Check
Install JT07065 Test Harness.
Install JT07066 Test Harness.
--
Check for control signal.
Typical voltage for slow idle is 2.5
volts.
Note
Engine stopped by fuel shut-off
If EC sensor has failed, engine
--
9025
solenoid. If solenoid fails, engine
speed learning procedure does not
15
turns over but does not start.
work.
2
Description of Operation
See Engine Speed Control System
See Engine Speed Learning Control
See Engine RPM Dial Speed
Operation in Group 9010-05.
Circuit Operation in Group 9010-05.
Control Circuit Operation in Group
9010-05.
Continued on next page
CED,TX08227,3177
1904JUN981/9
