Ditch Witch JT25 - Manual (Page 143)

Systems and Equipment - 142
JT25 Operator’s Manual
Diagnostic Codes
CMW
Diagnostic Codes
The JT25 is equipped with two diagnostic systems: engine and machine. The engine diagnostic system
detects critical and non-critical errors within the engine operating system and communicates fault codes on
the engine display. The machine diagnostic system detects essential and non-essential errors within the
automated machine control system.
Electronic Controlled Engine Overview
This unit is equipped with a self-diagnostic computer-controlled fuel management system. A variety of
sensors send input data to an ECU (Electronic Control Unit) that compares inputs with pre-programed
parameters and sends output voltage to a variety of actuators to adjust and operate the engine within the
specified parameters.
Warning indicators on the engine display tell the operator when critical and non-critical faults develop. Non-
critical faults occur when engine sensors detect moderate trouble with coolant temperature, oil pressure,
charge air temperature, or fuel temperature. Non-critical faults cause the operator alert indicator to light.
Critical faults cause the engine shutdown indicator to light. In both cases, a fault code is stored in the ECU.
If the fault corrects itself, the engine will gradually return to normal power. The alert indicator will continue
to flash until the trouble goes away, but a fault code will remain stored.
Engine shutdown will occur due to critical faults in engine coolant temperature or oil pressure. Before
shutdown, the operator alert indicator will light continuously and the engine will begin a rapid power derate.
If the fault does not improve in 30 seconds the engine will shut down.
Reading Engine Diagnostic Codes
Problems with the engine are indicated by a popup message box on the engine display. The popup
message is presented as either yellow for non-critical faults, or red for critical engine faults.
To hide/show active codes:
Press the soft key on the right next to the Hide icon. The message box will disappear, however the
Warning or Stop message will remain on the screen until the fault is cleared.
Diagnostic Codes
SPN FMI Warning
Color Circuit Error Description
27 4 amber EGR valve position voltage below normal, or shorted to low
source
91 3 red accelerator pedal or lever
position sensor 1 voltage above normal, or shorted to high
source
91 4 red accelerator pedal or lever
position sensor 1 voltage below normal, or shorted to low
source
91 1 red accelerator pedal lever
position 1 sensor frequency data valid but below normal operational
range - most severe level